Steve Hogg Bike Fitting Team

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Post Series: Foot Correction

A shim is a means to lengthen a functionally or measurably short leg while cycling. A shim stack may be needed as a short term, medium term or permanent fixture.  Above are 5 varieties of shims.  From left to right on top row they are:

1.  Time / Campagnolo / Keywin compatible
2.  Shimano SPD-SL / Look Delta compatible
3.  Look Keo compatible

And, on the bottom row from left to right:
4.  SPD mtb 2 bolt and clones compatible
5.  Speedplay compatible

We manufacture each shim type in 2mm and 3mm and thicknesses so as to allow a shim stack of any height from 2mm upwards in single mm increments.  For instance, below is a pic of a 7mm shim stack underneath a Look Keo cleat.  The shim stack comprises 1 x 3mm shim and 2 x 2mm shims.


Let me start by defining terms.

A Measurable Leg Length Difference (MLLD) occurs when there is a measurable difference in the length of one or more bones in one leg relative to the other.  This is commonly determined by observation and external measurement, though this method, even when competently performed, still has an error factor of plus / minus 5mm.  Better still, because it is definitive, is an X-ray, scan or MRI which will give certainty as to any difference in leg length providing it is taken properly.

Explanatory Note:
Many X-rays or scans for leg length are not definitive in terms of accurately determining LLD unless taken with knees locked out and the subject standing as tall as they can.  An X-ray is a 2 dimensional image and as something like 96% of people display a lateral pelvic tilt (my fitting clients over some years) which causes them to stand with one knee more locked than the other in normal standing posture, this means that the leg with the greater bend at the knee when the image is taken is ‘effectively’ shorter in a 2 dimensional sense, than it is with leg extended, leading to inaccuracy.  The X-ray is accurate as long as both legs are in the same plane.  The best protocol I’ve seen for imaging to determine relative leg length was given to me by Bernard Pearn-Rowe.  Bernard,  apart from being a knowledgeable bloke and Professor of Medicine, is a bike nut like the rest of us.  I’ve taken the liberty of copying it here:

“The accurate measurement of leg length is amazingly difficult. It can’t be done with a tape measure, and measurement of leg length on X-ray is much better.  But even this is complicated.  The measurement must be of functional leg length.  If a patient simply stands barefoot and gets X-rays taken, the eversion and foot posture that will almost certainly exist (as well as the impact of other postural issues) will distort the result and give a non-functional measurement.  Ideally, the rider should be X-rayed when standing and wearing properly adjusted riding shoes (including cleat wedges where appropriate) and the measurement taken from the washers around the screws locking the cleats to the shoe, to the top of the ball and socket hip joint.”

A Functional Leg Length Difference (FLLD) occurs when there are functional factors that effectively lessen the ability of one leg to reach as far towards the bottom of the pedal stroke as the other leg.  Some examples are:

a) A markedly tighter, hip, lower back, hamstrings or any combination of, on one side than the other
b) An unsupported arch that drops noticeably more on one foot than the other
c) Compromised ability to control a major joint involved in pedaling on one side. Usually because of excessive laxity resulting from a serious injury.
d) A functional pelvic asymmetry; i.e. an inability to sit squarely on the seat, which in turn can have a variety of functional and neurological causes.
e) Other functional issues that impact on the ability to extend the leg.  Perthes disease being one example.  Perthes disease causes malformation in the shape of the femoral head and acetabulum (ball and socket of hip joint), and I’ve seen several instances where one side was much more affected than the other.  Major knee injuries, a restricted range of motion in one ankle or surgically fused ankles are other examples.  There are others too.

What matters when fitting a rider to a bike is functional symmetry of movement.  The client in front of you wants a result today.  They may well be open to the idea of having X-rays taken or of consulting a structural health professional for a course of treatment that allows them to reduce or eliminate a functional difference in leg length; but right here, right now, they want a result that allows them to keep riding their bike for the physiological and psychological benefits they derive from it.  This is where shimming enters the picture.Ideally, if a rider is sitting as squarely as possible, and all of the factors that present challenges to on bike pelvic symmetry have been addressed to the greatest degree possible, then any remaining difference in pedaling fluency between legs needs to be addressed with a shim.  What percentage of riders need a shim?

The average of my clients over quite a few years is just over 29%.  I probably see a skewed sample of humanity as most people who seek our services have an issue that shimming may play a part in resolving.  In 20 odd years of bike fitting, I am still looking for my first symmetrical client so it comes as no surprise to me that close to 1/3 of riders need a shim.  Sometimes the shim may be as little as 2mm, which is why we make them.  So, how do you determine whether you need one?

Firstly, start by reading and applying the info in FOOT CORRECTION Part 1 and Part 2.

Next, ask yourself whether one leg feels stronger or more fluent than the other?

If the answer is yes, don’t automatically assume that it is the less fluent leg that is the problem.  You may be canting your pelvis toward the functionally shorter leg causing the functionally longer one to overextend.  Then again you may not.  If you perceive a noticeable difference in the fluency and drive of each leg, as a first step, mount your bike on and indoor trainer, warm up and pedal under reasonable load.  Now drop your seat 5mm and reassess. Most riders sit too high (see this link for more about this and read the postcript about indoor trainer choice) and as a result, most will autonomically pick a side to favour and a side to sacrifice because of this challenge to their pelvic stability.  The favoured side is the side that the rider cants their pelvis toward (most often the right side but not exclusively).  Did dropping the seat improve the equality of perceived effort of the legs?  That question has only 3 answers:  Yes, No or Maybe.  If YES, do you feel that both legs are functionally the same or very similar while you pedal, in terms of smoothness of stroke, equality of weight bearing on each sit bone and power production?

If the answer is still yes; then increase the resistance on your trainer to the point where you can still maintain pedaling technique but are working at the kind of intensity that you can only sustain for a couple of minutes.  Then ask yourself again if both legs feel much the same.  If the answer is still yes, then you don’t need a shim.

If the answer is no, read on.  If NO, drop your seat further in 3mm increments.  There will come a seat height where you either feel that both legs feel much the same, in which case you don’t need a shim; OR that one leg is feeling good but the other leg feels like it  is under extending and cramped.  The leg that now feels good may or may not be the one that originally felt more fluent depending on what your pelvis was doing by way of compensation.  You need to experiment with a shim stack under the now less cramped leg at a variety of seat heights.  The simplest way to do this is to fit a 3mm shim under the appropriate leg and raise the seat back up 3mm.  Does the cramped leg feel better now?

If yes, great.  If no, still a bit cramped, fit another 3mm shim and raise the seat another 3mm.  Experience tells me that of the majority that need a shim, the greatest number need a shim stack of between 2 and 6mm.  Any thing more than that suggests a marked MLLD or a substantial functional issue that needs addressing off the bike. It is worth getting an X ray taken by the method suggested by Bernard above. Alternately, a CT scan is more accurate than an X ray if taken properly.

Lastly, never assume that the less fluent leg is necessarily the problem side.  In many cases it is not.  When subject to any challenge to our position on a bike, we will all favour one side over the other (at a level below conscious thinking) and pay a price on the other side, large or small.  So, if shimming the less fluent leg doesn’t feel so good after a trial, shim the other leg and make an assessment.  See the table below.  If MAYBE, do as per NO.

This is about as simple as I can make this matter but it is not a foolproof method because it relies on your perceptions of what you are feeling and doing.  Many people have a false view of what they are doing in space on a bike.  It’s a human thing.  We lack the processing capacity in matters of motor control, most of which is unconscious anyway,  to be really accurate in our awareness of the detail of what we are doing in space. So we impose a mental veneer of symmetry on our actions.  In most cases this does not accord with reality.  For that reason, it is valuable for this exercise to have an observer present.  The observer needs to be standing above and behind you to determine which hip (if any) is dropping and which hip (if any) is twisted further forward than the other.  Additionally, they can provide an opinion on the relative velocity of the extension of each knee, which as you read in this post is the prime visual cue for seat height.

It is unlikely that your observer has had practice in what they are looking for so I will post some videos in an addendum to this post.  Before going further, below is some info from my records about shimming frequency:


This is a 3 year average of something over 1400 visits to us.  In that time, the shim stack height necessary ranged from 2mm to 24mm, and as you can see, the majority were on the right side.  Why?

Because as any physiotherapist, chiropractor or osteopath will attest, more people have a functionally shorter right leg than have a functionally shorter left leg.  The ‘why’ of that is a large subject in itself.

Above all, don’t think (as many do) that using a shim somehow makes you less than perfect.  You aren’t perfect anyway.  While perfect symmetry between left and right sides is an ideal to be striven for if your ambition is to ride a bike as well as you can with the least chance of injury, it is not attainable beyond an individually variable level. What we need is ‘functional symmetry’.  That means having both legs reaching through the bottom of the pedal stroke as evenly as possible, while sitting as squarely as possible on the seat and without creating a problem for either leg over the top of the stroke..

One important thing to remember.  As you increase the distance of the sole of the shoe from the pedal platform by adding a shim stack, you also increase the work load of the lower limb in stabilising foot on pedal.  This effect is called, ‘rocking torque’.  In simple terms, the increased distance that the shoe is set above the pedal platform acts as a lever, meaning that for a given degree of heel drop while pedaling, the foot rotates further back over the pedal than it would for the same cleat placement on the sole of a the same  shoe without a shim stack. In effect, during hard efforts (like climbing hard or forcing a gear on the flat) there is ‘effectively’ less foot over the pedal than the cleat position on sole suggests.

This is the major drawback with shimming.  So there are two choices.  Firstly, ignore the need to shim.  If you really need a shim, this is not a tenable choice.  Secondly, use a shim stack but in such a way as to minimise the increased rocking torque.

The second option means that as the shim stack height increases, the cleat needs to be moved further back relative to foot in shoe to give the same amount of ‘effective’ foot over pedal under high load as would be the case without a shim.  The problem is that moving the cleat further back increases leg extension (in most cases; some are atypical) which means that a larger shim is required, etc.  In practice, the best compromise is that for shim stacks of 4mm or less, ignore rocking torque as it will be barely perceptible for most riders.

For best compromise, for every 5mm of shim stack (up to and including 10mm), move the cleat back 1mm further than you would without a shim stack.  For example, if you have your cleat positioned so that the centre of the ball of the foot (see this post for how to determine this point) is 10mm in front of the pedal axle, then for a 5mm shim stack you will need 11mm and for a 10mm shim stack you will need 12mm.

For the small minority that need more than a 10mm shim stack, you will probably need to exceed the 1 in 5 ratio.  You will find that really large shim stacks need to be stable first and foremost.  The higher the shim stack, the more the cleat needs to be moved back on the shoe which partly negates the height of the shim stack because of the greater leg extension that usually occurs with a more rearward cleat position.  Some where between these contending requirements is an acceptable compromise.

One last word and a declaration of interest.  We manufacture shims.  So do Specialized and Speedplay.  Speedplay manufacture shims for their pedal systems only and there is no problem with them other than lack of choice of thicknesses, 3.5mm is it.  Specialized manufacture 3mm shims to suit a variety of pedal systems.  Specialized shims, like Specialized in shoe wedges, present a Material Challenge to the nervous system.  (For more about Material Challenges click here and here.)  If you are sceptical about my motivations in saying this, you are not the first.  All I can say is this; Specialized frames, seats, shoes and insoles are fine in this regard, but their shims and in shoe wedges are not.  I will demonstrate this on request and have done so, I would guess, several thousand times.  Including to some clients who own stores that sell Specialized products and subscribe to the BG fit system.  There is also a second problem with Specialized  cleat shims.  The shape closely follows the outline of the cleat they are intended to sit under.  This is the same  mistake that I made with our first generation of shims many years ago.  If multiple Specialized shims are are used, pedal entry can range from easy to difficult to impossible depending on rider and pedal system.

That is it for shimming.  There will be a Foot Correction part 4 – Foot Separation distance, in the near future.

Foot Correction seriesPart 1 – Arch Support and Part 2 – Wedging


Note: Often, more specific answers to your questions can be found in the Comments below or in the eBooks section and FAQ page.

To learn more about bike fit products offered by Steve, click here.

Do you have a bike fit success story? Please go here to share.

Thank you for reading, return to the Blog page here or please comment below.

Comments are closed for most posts not part of the subscription blog. If you have a question or comment, Prime members can use the Prime Q&A.

This Post Has 77 Comments

  1. steve, i have a 1/2" shorter right femur and have tried various shim thicknesses (2mm-9mm),
    never feeling square on the saddle. the best feeling seems to be a combo of shimming/offset cleat position. i am thinking of trying a 5mm shorter crank arm on the shorter leg side, what is your experience with this?

  2. G'day Anonymous,
    The likely source of your dissatisfaction is the asymmetries you've developed off the bike that you carry onto the bike. Having a 1/2" shorter right femur will be part of the picture of asymmetric function but not the entire story by any means. For instance; are both of your feet the same size?
    Do you stretch regularly and sensibly? That means holding stretches for longish periods at low intensity (2 – 3 on a 1 – 10 scale with 10 being agony).
    Do you compensate for your leg length difference in your walking shoes with a heel lift or similar?
    You should because you spend far more time off the bike than on the bike but the issues you develop in your life off the bike (where they probably affect you less) then transfer onto the bike where you have less tolerance for asymmetry because you are locked into a more or less fixed relationship with a bike.
    And so on ad infinitum. What I'm saying is that the source of your dissatisfaction is not likely to be your shorter femur per se, but because of a combination of factors of which your femur discrepancy may be one.
    I'm not sure what you mean by "offset cleat position". Different position on each shoe? Different lateral offset?
    I'm not a fan of different crank lengths unless it is the least worst of only bad options. You already have a shorter femur (primary lever) which means at some level, that leg is having to work harder in a muscular sense to produce the same amount of torque as the longer leg. If you reduce crank length, you further increase this disparity meaning that the shorter leg has to work even harder still. Before even considering differing crank lengths, I would be resolving all the other potential reasons for your inability to sit squarely.

  3. I do stretch and where a lift in my shoe. I guess the best way to describe
    How I feel on the bike is windswept. My left leg collapses inboard and my
    Right leg seems to bow outboard. I only get saddle sores on the left side and
    Have cracked a few saddle shells from my left sit bone. Right now I am running a wider right spindle otherwise my right foot hits the crank arm, my left foot
    Has all kinds of room. My left foot rolls in and my right side supinates. I have gone up to 5 wedges on the left but that doesn't help, never any pain
    Though on the left side. Right side I had IT band issues but stretching has
    Resolved that.

  4. G'day Anonymous,
    I have cut and pasted your reply above and commented in your text in capitals.

    I do stretch and where a lift in my shoe. GOOD I guess the best way to describe
    How I feel on the bike is windswept. My left leg collapses inboard YOU ARE DROPPING AND / OR ROLLING YOUR LEFT HIP FORWARD AND DOWN. and my
    Right leg seems to bow outboard DROPPING OR ROLLING THE LEFT HIP FORWARD AND DOWN IS WHAT IS CAUSING YOUR RIGHT LEG TO MOVE FURTHER FROM THE CENTRE LINE. I only get saddle sores on the left side and
    Have cracked a few saddle shells from my left sit bone BECAUSE YOU ARE DROPPING THE LEFT HIP. Right now I am running a wider right spindle otherwise my right foot hits the crank arm, THE LEFT HIP DROP CAUSES YOU TO EXTERNALLY ROTATE THE RIGHT HIP AND HITTING THE CRANK IS THE RESULT AS THE HEEL TWISTS FURTHER INB0ARD. YOU ARE NOT SITTING SQUARELY ON THE SEAT. YOU ARE SITTING LEFT HIP FORWARD. my left foot
    Has all kinds of room. My left foot rolls in and my right side supinates. I have gone up to 5 wedges on the left but that doesn't help, never any pain SURPRISING ABOUT THE LACK OF PAIN
    Though on the left side. Right side I had IT band issues BECAUSE THE PLANE OF MOVEMENT OF THE RIGHT HIP IS CONSTANTLY CHALLENGED BY THE LEFT HIP DROP but stretching has

  5. So if my left leg is longer what would cause
    Me to sit left hip forward and drop the left hip?
    Simple geometry says a shorter right femur
    Would pull my right hip forward wouldn't it?

  6. Geometry doesn't have a lot to do with how humans sit on bikes. What influences that is mechanical, neurological and developmental differences between left and right sides. The problem for me in commenting on queries like yours is that it is best likened to an incomplete jigsaw puzzle. Very incomplete. Because I don't have all the pieces (i.e, one on one assessment and direct contact) I have to advise based on the playing the odds of what experience suggests is the most likely occurrence based on what you have told me. That is what I have done. Is it the only possibility?
    Not at all, but what I have said is the most likely.
    For you to be certain, you will need an observer to stand above and behind you while you pedal under load on a trainer with your shirt off. The observer needs to tell you which hip is sitting forward and which hip is dropping under load on each pedal stroke of that side. The hip drop and forward movement may be happening on the same side OR one hip will sit forward while the other drops. Let me know.

  7. Thanks so much for this tremendous resource Steve. It's good reading and is providing a lot of help to many folks. So my question is pedal related. You talk about shoes, arch supports, insoles, canting devices, shimming devices, but NEVER pedals. So let's hear it. Is there a system or systems you find works better overall? I know many other questions would need to be asked and answered to answer that one in particular but hearing your thoughts on teh subject of pedals would be great. Thanks.

  8. G'day Jonathan,
    This blog has only been going for a couple of months and is a means for me to clear head space. All in time. I'll get to it.

  9. Steve,

    I've been riding with your 3-3mm bolt universal cleat shim for the past few weeks (1 shim and a few wedges–total 5 mm). I was still tipping and felt I needed more. I added 1 more of you shims and stacked two lewedges (1mm) and two additional wedges for canting. This has caused some serious pedal 'rocking' (up and down). My question is a simple one. I have the Look blades and I'm wondering if I need the Look Keo shim?, or is it just the pedal? I had no rocking problem with the orginal 5mm set up.

    Thanks so much,

    Your biggest fan! 🙂

  10. G'day Anon,
    Can you be more specific about 'rocking'?
    Do you mean vertical slop?
    Or slop in another plane?

  11. Great stuff. Please keep the blog going. Valuable information. Arch support post has helped me and I'm going to start a "Wedge Ride" this week.

    Thank you.

  12. Hi Steve,

    Thanks for the response. I suppose I mean vertical plane. Foot is going from supination to pronation. It's the cleat that no longer sits correctly on the pedal. If I put the cleat directly on the shoe there is no movement (everything is secure and stable. Anything else creates vertical movement (supination/pronation. I don't have to be attached to see the rocking. I have attached the shoe to pedal and observed it is something to do with the cleat and pedal interface.

    Thanks so much.

  13. G'day Anon,
    You are using a combination of our Time / Campag Pro Fit / Keywin compatible shim with a Keo cleat plus counter stacked cleat wedges to gain some extra shim stack height. It might be the shim type you have chosen that is the problem but I doubt it. The only problem I've come across with Keo users using the T/C/K shim is that because the Keo is a shorter cleat than the T/C/K shim was designed for, torquing up the cleat doesn't force the front edge of the shim to conform closely to the curve of the sole of the shoe in some cases. When this happens, pedal entry can be ddifficult because of the leading edge of the shim 'hanging' with a gap between shim and shoe sole. There should be no gap.

    The shorter length of the Keo shim eliminates this problem. I suspect it is the use of counter stacked cleat wedges as part of the shim stack. They may (I say cautiously) be fouling the pedal. Using counter stacked cleat wedges as part of a shim stack is not something I need to do, as 2 and 3 mm shim varieties take care of any shim stack requirement from 2mm upwards in single mm increments.

    I would suggest Keo compatible shims only to give you the shim stack height you require. I would be very surprised if that doesn't solve the problem. Let me know.

    Another suggestion is that you don't combine cleat wedges with a shim stack on a 3 bolt shoe unless there is no other choice. I would suggest cutting down your cleat wedges (maximum of 3) and fitting them underneath the heel of your shoe insole as per the pic at the bottom of the post Foot Correction part 2: Wedging.

  14. Hey Steve,

    I went out and bought the look keo shims today. I can't believe my shop had them!! I removed the wedges and taped them to my heel (as per the Hogg method) However, the rocking hasn't disappeared unfortunately. There is a gap at the front (as you mentioned) so it doesn't conform completely to my soles. Not sure if that could be the problem? I don't have trouble getting into the pedal because of the gap. Your help is super appreciated. I'm the most comfortalbe I have ever been on a bike since implementing all your techniques….even if I am currently in bike fit hell.



  15. G'day Greg,
    I've just bolted a Keo cleat to 5 different models /sizes of shoes. In each case there was lateral rocking possible without a shim being used. I then repeated the task on each of the shoes with a 3mm shim inserted between cleat and shoe sole. For each of the 5 shoes, I used the most forward adjustment and most rearward adjustment possible for the Keo cleat. In each case there was lateral rocking to a similar degree as without a shim. Please recheck whether there is rocking without a shim. If there is not, please send me a pic of of the side view and front view of cleat and shim mounted to shoe sole. Our email address is

  16. Hi Steve

    re fitting of trimmed-off 3-hole yellow heel varus wedge sticky-taped to the bottom of the shoe insole shown in earlier post….

    Why not use a purple 4-hole Speedplay wedge instead of 3-hole Shimano wedge and save the cutting? Would it not provide a more fool-proof solution for those needing 1 or 2 heel varus wedges?

    Yuri B (May 2008 Hogg-cyclefit veteran!)

  17. G'day Yuri,
    It has been a while. I've tried what you suggest without success though I'm not certain as to the 'why'.If you look from above, the Speedplay wedges are rounded in the centre section which means that they don't fit well into the heel of a shoe. When I excised the rounded edges leaving a rectangle (more or less), they don't cover the width of the heel of the insole. When I found they were problematic under the heel I didn't bother spending a lot of time working out the 'why' because there was an already effective alternative in the 3 bolt BFS cleat wedges.

  18. thanks for the reply Steve. Terrific blog!

    Regarding the photo of the blue insole with trimmed 3-hole yellow wedge – can you please annotate it for me – which side is the "trim" – I presume the thin side is trimmed? And on photo is it the left insole with a varus thick side untrimmed? I am trying to duplicate your setup with 1 varus wedge on the right insole. Thanks again.
    Yuri B. Melbourne.

  19. G'day Yuri,
    Yes, trim the thinner edge to allow the cleat shim to fit the outline of the heel of the insole. Theoretically, it makes more sense to trim the thick edge because then a stack of 'heel' wedges would take up less vertical space for a given degree of cant. As you will find if you trim the thick edge, the cut will pass straight through one of the slots and it makes the 'heel' wedge fit the insole less well. So thin edge it is.

  20. Hi Steve,

    I took the shims out and tried. There is still lateral rocking!!! This is substantial rocking. I tried 3 different shoes that I had lying around and tried with different cleats (I have 4 new sets of cleats–gf uses look too). They all had lateral rocking but not to the extent that this shoe is producing. I actually got rid of my speedplays a couple of months ago because of this rocking (switched to look because I was told speedplay causes lateral rocking). I'm now thinking it could possibly be my shoes?? Brand new top of the line Norhwaves bought last year. Perhaps the construction of the sole was a bit off, or the lateral rocking of the speedplay caused me to warp the sole?? Possible?

    Thanks Steve.


  21. G'day Greg,
    I thought that may have been the case. I could not understand why the shim would cause rocking unless the cleat rocked without a shim because torquing up the cleat mounting screws forces the shim to conform to the curve of the sole. I haven't had a lot to do with Northwave shoes; only enough to comment that the cleat mounting holes are too far forward for a lot of riders. But that wouldn't have anything to do with your problem. I can only assume that something about the shape of the curve of the sole, either laterally or fore and aft is distorting the cleat causing it to not sit square to the cleat contact area of the pedal platform.
    Check whether there is rocking present on the other side?
    You haven't mentioned any so I imagine there are only 2 possible answers to that:
    1. Yes but you hadn't noticed it.
    2. No

    If 1. then the rocking is unlikely to be the problem. More that the left leg is either over extending or that it's plane of movement is being challenged.
    If 2. then you have a problem with the shoe or cleat / pedal. Has the upper surface of the pedal platform where the cleat contacts it have any wear?
    Any depressions or noticeably worn areas?

  22. Steve,

    There is rocking on the left leg, but it is very minimal, and if I press down hard enough it isn't there at all. My cleats are all new, and pedals are new. I have tried two of my GF's shoes and there is no rocking. The right side rock is present in my shoes with or without me in them. I didn't want to bother you with my history because I'm sure you are extremely busy, but I am at a lost!

    Here is a brief history of my situation, and what I have been doing lately:

    Left side pirformis is knotted, and my left Psoas, Left side (low back, abs, hip hamstring, tfl, itb) all work as one (sitting twisted on bike. Obvious pain is in all those areas on left side. More pressure on left foot, tight left calf, sciatica years ago when it started (1996).

    Right side-fine, but my foot struggles a lot. Right foot pronates (tibial rotation). Right "sit down" bone was hurting a lot.

    Recently, started ART and Massage Therapy consistently. It was helping, but pain was still present.

    I started reading 'everything' I could find that you have written, and in the last month I have:

    -Put two wedges under the left side (varus), two 3mm shims under the right with two varus wedges on right as well.

    -Currently using orthotics, but waiting for esoles to come in.

    -using 'shape' shoes, bought overcoming neck and back pain (stretching like crazy)

    -xrays standing–showing scoliosis, right hip dropped and tilted forward. Right femur sitting approx. 4 mm below left.

    -Moved seat down a few mm, and twisted it slightly to left.

    Currently, left side is feeling much better. The Art and MT is seemingly becoming more effective and my left glute, psoas, etc. is working itself out. Thank you so much!

    Perhaps my situation caused the shoe warping? I wish Australia wasn't so far from Canada!

    Thanks for all the help and info. you provide! I wish I knew you you 10 years ago when I racing in Europe and struggling with this problem.



  23. Re: xray recommendation for LLD…

    If you don't know your ideal cleat/wedge arrangement, I suppose you just recommend taking the xray in shoes with zero wedges? Since the foot would sit with the heel lower than the toe, wouldn't the metatarsals obscure the tibia?

    If you don't know your "ideal" insole arrangement, do you suggest that a person uses none for the xray, or a pair of esoles that are equal in terms of support, or to not take the xray until you have determined the correct amount of support (e.g., black in left shoe, blue in right shoe)?

    The recommendation said you measure from the cleat. So is the cleat then the lower end of the tibia measurement? And the femurs would be measured separately?

  24. G'DAY GREG,

    There is rocking on the left leg, but it is very minimal, and if I press down hard enough it isn't there at all. My cleats are all new, and pedals are new. I have tried two of my GF's shoes and there is no rocking. SOUNDS LIKE A NEW PAIR OF SHOES ARE IN ORDER.The right side rock is present in my shoes with or without me in them. I didn't want to bother you with my history because I'm sure you are extremely busy, but I am at a lost!

    Here is a brief history of my situation, and what I have been doing lately:

    Left side pirformis is knotted, and my left Psoas, Left side (low back, abs, hip hamstring, tfl, itb) all work as one (sitting twisted on bike. Obvious pain is in all those areas on left side. More pressure on left foot, tight left calf, sciatica years ago when it started (1996).PROBABLY A PRE EXISTING PROBLEM THAT BECAME CHRONIC AFTER RAN OUT OF WAYS TO COMPENSATE

    Right side-fine, but my foot struggles a lot. Right foot pronates (tibial rotation).Right "sit down" bone was hurting a lot. IS THE RIGHT SIT BONE PAIN OCCURRING BECAUSE YOU DROP THE RIGHT HIP AND MAKE THE LEFT LEG EXTEND MORE OR BECAUSE YOU DROP THE LEFT HIP AND MAKE THE RIGHT LEG EXTEND MORE? EITHER IS POSSIBLE.

    Recently, started ART and Massage Therapy consistently. It was helping, but pain was still present. TELL ME WHERE YOU LIVE AND I'LL ATTEMPT TO POINT YOU AT SOMEONE WHO CAN DETERMINE ROOT CAUSES.

    I started reading 'everything' I could find that you have written, and in the last month I have:

    -Put two wedges under the left side (varus), two 3mm shims under the right with two varus wedges on right as well.


    -using 'shape' shoes, bought overcoming neck and back pain (stretching like crazy)I ASSUME YOU MEAN MBT OR SKECHERS FOOTWEAR?

    -xrays standing–showing scoliosis, right hip dropped and tilted forward. Right femur sitting approx. 4 mm below left. MEASURABLE BONE LENGTH DIFFERENCE OR FUNCTIONAL DIFFERENCE AS RESULT OF SCOLIOSIS?

    -Moved seat down a few mm, and twisted it slightly to left.

    Currently, left side is feeling much better. The Art and MT is seemingly becoming more effective and my left glute, psoas, etc. is working itself out. GOOD Thank you so much!


    Thanks for all the help and info. you provide! YOUR WELCOME I wish I knew you you 10 years ago when I racing in Europe and struggling with this problem.

  25. G'day Eric,
    Sorry, I initially missed your comment. Bernard's recommendation is as written; though I should have been more clear. My practise is this:
    I'm not concerned whether a rider has an measurable LLD or not. If there is a substantial LLD it is obvious. If an LLD is small, sometimes if is obvious, sometimes it is not. I find that my assessments accord with x rays 90 odd % of the time and are at variance the rest of the time. Bike fitting isn't as simple as "Right leg is 5mm shorter so right cleat needs shimming".

    The question any rider or bike fitter needs to ask themselves is "What is the functional picture?"
    For instance, is one foot longer or of different proportions to the other?
    Does the rider sit reasonably squarely on the seat or drop to one side?
    Is there a marked difference in range of movement between sides in the hips, lower back and hamstrings? Etc, etc.

    Each of these things adds or subtracts a functional component from what may or may not be a measurable LLD and so affect functional leg length equality (or inequality) on a bike.

    More often than not when I suggest an X ray or scan for leg length, it for the benefit of the client off the bike that is my interest. I have already made an assessment of what was required on the bike. However, we all spend far more time off the bike than on the bike and the asymmetries we develop because of postural anomalies off the bike contribute to the functional picture on the bike. So to put any uncertainty to rest, I often suggest an X ray or scan so that the rider knows whether they have to –
    a) consider a heel lift or build up in one shoe because there is a measurable LLD.
    b) sort out their postural and flexibility issues because we already know that there is a functional LLD.

    Lastly, my personal preference for X ray or scan for this purpose (life off the bike) is cut and pasted from a booklet I give fit customers below.

    Consider seeing:
    A health professional for a referral for a standing, load bearing Xray or scan with both knees locked and with the relative height of the femoral heads noted. You will need a front on shot and a side on shot so as to determine whether both halves of the pelvis are in the same plane.

    I hope this answers your question more fully.

  26. Hi Steve,

    I'll be looking for new shoes today!! Do you have any thoughts on Bont shoes?

    A person in Saskatchewan. would be much more ideal–much closer. If he doesn't work out, maybe I'll come down and spend a few weeks training! We could definitely use someone here.

    I just answered some of your questions here:

    I drop the right hip and internally rotate that leg and hip towards the top tube. Left hip and leg sit further back on the seat and rotate outwards. I drop left heel substantially and right foot points down. Never, have I gone with different cleat positions. In other words, I have always ensured perfect asymetery between the two shoes. My right foot is slightly smaller. I originally put the lift on the left leg, but the painful areas became increasingly inflamed.

    I live in Ottawa, Ontario, Canada

    yes, the Skechers

    I have no idea. I didn't even know I had scoliosis until last year when they took a chest xray. I just did the xray that you suggested in your articles



  27. G'day Greg,
    Bont's are fine providing they fit. The Vapour (Vapor?) is the pick of them for road riding. Fit can be an issue because they are a carbon bathtub style shoe. The sole comes up and holds the foot all around the edges. If your foot fits great. If not, they can be heat molded but I know a few people who have stuffed that process up and cost themselves $$$$ in the process. Shoes that don't seem to give my customers problems are: Specialized, Shimano, Sidi, Diadora, Gaerne and Lake. Whatever fits best is the one to choose and don't be tempted to go up a size to get width. If you have a wide foot, both Shimano and Sidi make extra width versions.

    I'll let you know how the gent from Saskatchewan goes. At the moment it is a serious approach for training but nothing signed or sealed yet.

    Okay, you have a slightly shorter (if the method used to take x ray is solid) right leg and a slightly smaller right foot and from the sound of it, really struggle to reach the pedal on the right side. 4mm of femur difference on the right is not enough to cause everything you have described unless there is other stuff going on. When you shim the right foot do you feel that you sit more squarely?

    Or do you merely extend the right leg less and keep dropping the right hip?

    If the latter, you need off the bike help to knock you back into some sort of functional shape. There are some people here who are really good at getting to root causes of all sorts of issues and they've helped a number of my 'problem children'. I asked for recommendations for your part of the world and they've given me the 2 names below.

    DC, DIBAK Boehnke Hans
    134 Main Street N.
    Markham ON. L3P 1Y3

    DC, DIBAK Gleeson Dan
    1304 Victoria Ave.
    Thunder Bay ON. P7C 1C2

    The scoliosis will almost certainly be a product of the other structural stuff going on.

    I need answers to several questions.
    Firstly, you will need a helper who knows how to locate your posterior iliac crest on each side. If you have a physio, chiro, anatomy student etc that you know, they will be ideal.

    A. Sit on a low unpadded stool with your helper behind you. Have them locate your posterior iliac crest (PIC) on each side. Are they level while you sit?
    If yes, proceed. If no, let me know.

    B. Stand in front of a mirror in bare feet with your shirt off. Ask your helper to locate your PIC on each side and record the approximate difference in the height of them.

    C. Stand as tall as you can while keeping heels on floor, chest up and neck extended (that is chin slightly lowered). Keep breathing in this position and have your helper locate the PIC's again. Has there been any change in the relative heights and if so, what was it?

    D. Stand again in bare feet facing the mirror in normal (for you) posture. Cover your left eye and have your helper locate the PIC's again. With left eye covered is there any change in PIC height difference as found in B.? If yes, let me know. If no, repeat procedure with right eye covered and let me know the outcome.

    E. Stand again in front of mirror but with Skechers on. Have your helper locate your PIC's again. Was there any change in relative heights from B.?

    Let me know. Also, VERY important that your helper remove their hands from your PIC's before each task is done.

  28. Steve,

    Thankfully I have a loving fiancee who just happens to be an xray tech.

    I had an xray done again last night–fiancee made me stand properly, not letting me pronate as I did originally. I was essentially standing normally. Results, very little noticeable difference this time. With the 6 mm lift I am feeling as if I sit more squarely, but I also twisted the saddle slightly to the left. Both arms are reaching the handlebars evenly and I don't feel twisted on the bike as before.

    Not sure, I think I keep dropping the right hip, but I'm definitely feeling that the muscles on the right leg are being engaged and the left leg muscles are now being turned off. PreviousLY, the left leg muscles and glutes were hard as rock throughout pedal stroke and right were nice and soft. )

    Steve, I have cut and pasted your questions below with my answers in CAPS.

    A. Sit on a low unpadded stool with your helper behind you. Have them locate your posterior iliac crest (PIC) on each side. Are they level while you sit?
    If yes, proceed. If no, let me know. (YES)

    B. Stand in front of a mirror in bare feet with your shirt off. Ask your helper to locate your PIC on each side and record the approximate difference in the height of them. (LEFT APPROX. 3 MM HIGHER THAN RIGHT)

    C. Stand as tall as you can while keeping heels on floor, chest up and neck extended (that is chin slightly lowered). Keep breathing in this position and have your helper locate the PIC's again. Has there been any change in the relative heights and if so, what was it? (YES, THERE WAS A CHANGE–PIC EVEN)

    D. Stand again in bare feet facing the mirror in normal (for you) posture. Cover your left eye and have your helper locate the PIC's again. With left eye covered is there any change in PIC height difference as found in B.? (YES, LEFT PIC BECAME LOWER)

    If yes, let me know. If no, repeat procedure with right eye covered and let me know the outcome.

    E. Stand again in front of mirror but with Skechers on. Have your helper locate your PIC's again. Was there any change in relative heights from B.? (YES, THEY WERE EVEN)



  29. Good Greg,
    Now you may be getting somewhere. My comments below assume that everything was done perfectly. Otherwise…………….

    A = YES means that you don't have a small hemipelvis. 0.5% of the population do and I needed to eliminate that possibility as a variable.

    B = 3MM HIGHER ON THE LEFT is too small a difference for certainty about anything, unless your fiancee has a very good eye for this sort of thing.

    C = EVEN ILIAC CREST HEIGHTS means that there is a postural component in your minor pelvic tilt. Just as there is for the 96% of the people I see who display a lateral pelvic tilt.

    D = YES, THERE WAS A SHIFT means that there may be visual processing component to your problem. I say 'maybe' because you say that "….the left became lower" but don't say whether it was lower from reference B OR lower than the right side. I'm used to seeing more than a 3mm shift if that is what it was. Visual processing issues with the spatial awareness component of the sense of vision, usually via the non dominant eye are common. So anyone affected has a skewed awareness of what 'upright' is resulting in shift in the pelvis to accommodate that skewed awareness. If the appropriate eye is covered, closed or uses the individually correct colour frequency of lens tint, then the pelvic tilt resolves in standing posture. The question is whether this is part of your functional picture when you ride. There is a definitive test that I use but it doesn't lend itself to email transmission. So…….get on a bike and ride down the street (not on a trainer where the bike is held upright without effort from you) with your left eye closed for long enough to determine whether you feel more square on the seat and more balanced between legs on the pedals than usual. Be careful while you do this!
    Far less people are affected by this visual processing of the spatial awareness component of vision while riding in a prone position than are affected in standing posture. Let me know what happens though.

    E – SKECHERS FOOTWEAR SQUARE YOU UP PELVICALLY confirms that you have a posture / core strength / functional stability issue. That should be the focus of your efforts to resolve this. You need to be a core strength superman or at least attempt to be. Have a look at this link
    and get to work.

    Don't forget that the most important core exercise that you can do at any time, almost anywhere is to stand and sit as as tall as you can.

    Also, when not wearing your Skechers, make sure you have good arch support in your walking shoes as this will help too.

    It sounds like you are getting somewhere on the bike. Keep using the 6mm shim as it sounds like a positive; at least for the time being. As you improve your posture and function (and keep in mind that your feet play a part in this, hence the need for Skechers or quality arch support, don't be surprised if you need to reduce the shim over time.

  30. Transferred over from prior blog in order to reply…

    Hi Steve,

    I tried riding with my left eye close. I did this a few times out on my ride today. The result was, ‘no change’ in feel! I would imagine that is a good thing!

    Thanks for all the help. My power has increased substantially in the last few weeks due to the comfort and changes I have made. These are numbers I use to put out back in the day when I was racing in France. I really hope my power meter isn’t off! 🙂

    I’ll keep the 6mmm in for now as you suggest! My only thought is could I be doing something more effective? I looked at my before video and it appears that I was sitting with my right hip forward, left hip back with the left hip (when viewed from behind)moving up and down more (dropping?). I beleive this makes sense based on all the tests that you had me do and why the 6 mm shim is working. I hope I’m right.

    Thanks again,

  31. G’day Greg,
    The “no change in feel” is a good thing providing your also tried with the right eye shut too. I’m glad to hear that you are performing better and
    Could you be doing something more effective?
    In the short term no. In the longer term, yes. That assumes of course that you can track down the root causes of your pelvic asymmetry on bike; whether it be a functionally short leg, muscle imbalances or whatever and work towards resolving them. Performing an all of body stretching routine properly is a hugely undervalued performance nehancement. “Properly” means holding each stretch for at least 60 seconds at an intensity of 2 – 3 on a 10 point scale with 10 being agony. Most riders, particularly males, stretch far too hard if they bother to stretch at all. The most accessible book I’ve seen is “Flexibility for Cyclists by Fred and Kele McDaniel available at

    Best of luck with your riding and stay upright!

  32. I’ve been following your and Greg’s conversation, and I drop my left hip considerably. Shims and stretching have improved the drop, but I tried riding with each of my eyes closed today on my ride (not at the same time). With my left eye closed, no difference. With my right eye closed, my right leg seemed to fire better and make my hips “feel” equal. Should I become a pirate on the bike?

    1. G’day Jason,
      I’ll explain what you are feeling. Neurologists tell me
      that something like 90% of the information we derive from our environment enters through the optic nerve. Moreover, something like 20% of the optic fibres are not for seeing but play a part in balance, coordination and spatial awareness. Many people don’t process information of this type (the non seeing 20% of of the sense of vision) well from the non dominant (in most cases;there are exceptions) eye. That means that affected people have a skewed
      awareness of what upright is and change their posture to accommodate that skewed awareness. Do this for a lifetime and it will result in physical changes in terms of left / right muscle balance and patterns of flexibility.
      So this skewed awareness of ‘upright’ becomes more or less fixed and affects every physical action we perform in the sense that when we think we are functioning symmetrically, we are not.

      How many people does it affect?
      A lot. I test for this sort of thing with fit clients. Currently,of the
      several hundred new fit clients I would see in a typical year, 95% display a lateral pelvic tilt in standing posture, with or without a leg length discrepancy with the breakdown being (round figures) 56% with left iliac crest high and 39% with right iliac crest high.

      For 89% the pelvic tilt disappears ( if there is no leg length difference) or moderates noticeably (if there is a leg length difference) if the subject covers the appropriate eye. The breakdown (round figures) for this is left eye closed improves pelvic symmetry for 80% and right eye closed works for 9%. Don’t forget, all of this is in standing posture.

      The question is for how many are positively affected when riding a bike which chiefly differs from standing posture in having a flexed lumbar spine.
      The answer is that it is a much smaller number. I don’t have figures for how many as I don’t track this statistic but would guess it to be around 15% and it appears that you are one of them.

      I’m the last person to suggest that the on bike affected 15% should ride around with one eye closed. Not real safe! The same positive effect on on bike symmetry can be achieved with both eyes open if the rider wears the individually correct colour frequency of lens over the appropriate eye of their riding glasses. There are four colours that I’ve come across. One or the other (but never more than one for an individual) will enhance on bike symmetry for affected people. I will contact you privately about this and we’ll work towards a solution. Once we work out the colour, you will need to see an Optometrist, preferably a Behavioural Optometrist, to have a lens
      made for your riding glasses for the right eye in the appropriate colour frequency.

      1. Steve

        That is very interesting. My son has Irlen Syndrome and has to wear color corrective lenses due to the way certain wavelengths of light mess with the optic nerve transmissions. His reading level jumped from sub kindergarden to age appropriate within a month of getting glasses. I suspect there is something similar here. Very interesting indeed.


      2. G’day Craig,
        Yes, it is similar. I was aware of the effect on information
        processing that coloured filters have on susceptible people but was a little
        surprised when I stumbled on a similar effect on pelvic symmetry and posture
        a few years ago. Particularly as the pelvic / postural stuff affects a large
        majority of people off the bike. When I worked this out, I contacted the
        local Irlen people but it was news to them. I also contacted Behavioural
        Optometrists and Chiropractic Neurologists because I know that both
        professions use coloured filters for various things. A Behavioural
        Optometrist gave me the strong impression that the postural effects were
        known to the profession but I have since found out this isn’t the case.

  33. Have you posted video of posterior knee extension in telling seat height
    ? I saw you mentioned and I could not find. If not I would love to see to help me with this issue. I love your video examples. Great blog! I feel so strongly about that opinion I would like to make a donation to your cause if you tell me how I can do that through something like paypal or other.


    1. G’day Bill,
      I’ve shot footage of several riders but aren’t happy with what I’ve done to date. The resolution of video footage when posted isn’t a patch on ‘in the flesh’. I’m trying to come up with examples that show what I mean without being grossly obvious or so subtle that it is lost in the lower resolution that is all that the current state of technology will allow.

      I should have something up by late next week.

      Re your kind offer; you’re very generous. The best I can have is for you to keep reading the site. You will see it expand bit by bit with articles, downloads, new posts etc. Save your money until I get ‘the book’ on bike fitting written. Once the site is up and running the way that I want it to (and a huge thank you to Jason Warner for his ongoing efforts) I will write an accessible book on bike fitting. It is something I have been wanting to do for a long time. My first conception was a manual for bike fitters but I’ve realised that what is necessary is more of a self help manual outlining a process and principles that will most riders to fit themselves well.

      If I set myself the goal of say, 5 pages a week with photos and so, it will be finished within a year of starting.

  34. Hi Steve
    What is the net effect on saddle position if changing to a longer length of crank [165:170 in my case + 155:165 for the wife]-i’m really thinking of fore+aft rather than height?

    Me & the mrs ride relatively small off the shelf frames:52cm tt;
    I can just about find a ‘balanced forces position’ that you describe ,with a long railed saddle slammed right back eg arione + standard [25mm] setback post;
    because women’s saddles tend to be shorter railed ,she fits it difficult to get back far enough with a standard seatpin.
    Are there any [cheaper] alternatives to the fsa k-force sb35 seatpost that you know of?

    1. G’day Doug,
      The nett effect……fore/ aft etc? Assuming all else is fine, lengthening the crank by 5mm will require to drop the seat post 5mm further into the frame to maintain the same seat height as measured from pedal axle centre to top of seat. As the seat drops 5mm (relative to the top tube) it will move forward approximately 1.7mm. In other words, 3/5 of stuff all. The feet being a maximum of 5mm further forward in relation to the bottom bracket centre, because of the increase in crank length, should offset any miniscule transfer of body weight forward resulting from the change in seat position.

      Just a clarification. A Fizik Arione is a poor choice if you are trying to get you backside further behind the bottom bracket. While they have a decent rail length, the placement of the upper relative to the rails as well as the placement of the seat shoulders relative to upper length means that there are plenty of other seats out there that will give you a more rearward body position in space for similar seat placement fore and aft. SMP are the pick in this regard.

      Re your wife; have a look at an SMP Lite 209. Very long rails, rearward seat shoulders (meaning that the rider sits a long way back on the seat relative to the seat upper length), plenty of padding and so on. The angle of the seat relative to horizontal is crucial for comfort. If you lay a digital level along the long axis of the seat (not through the cutout in the centre but along the top edge of one side) the seat should be positioned anywhere from level to 5 degrees down at the nose. In simple terms, more flexibility and ability to extend lumbar spine = greater nose down angle.

      I hope this helps.

  35. Hello Steve,
    This blog is a fantastic resource. Cant thank you enough for taking the time to dive into people’s questions and provide insightful and thorough responses.
    A few years back I had a bad knee surgery on my left side. After a few years off the bike I came back and started riding again. I was using an older pair of Shimano dura ace cleats (from 2006).
    Although I notice a small amount (very small) of left hip drop at that time I didnt think much of it and it never caused any issues for me.
    Then last year I really began increasing ride frequency again and participating in some ultra distance stuff. All year long I battled right IT issues. By using a varify of wedging technique on the right I could moderate the IT issues but nothing really fixed the problem.
    Then over the winter I switched to speedplay pedals with a much lower stack height. Now my left hip drop is very pronounced and I feel like I am falling off the left side of the saddle when I try to ride hard. As a result my IT issues have reached a new level. If it wasnt for regular graston technique treatments and my pilates teacher wife I would be completely off the bike.
    I have tried 3mm of shims on the left side without any luck. I lower the saddle about 5mm but no luck. I havent tried shimming the right side yet.
    Any insight here would be appreciated.
    Have a great night.

    1. G’day Jonathan,
      thanks for the positive comments. The time is fast approaching though, where I may not be able to answer all Comments. Very,very time consuming and time is something that I don’t have a lot of.
      Anyway, to your issue. In almost all cases, an ITB problem, if bike position related is caused by a hip drop or forward rotation on the other side. You’ve tried a 3mm shim on the left and a seat height drop of 5mm on the right and are now looking further afield for solutions. The problem is almost certainly related to your left hip drop. I would suggest this approach.

      Drop your seat to whatever height is necessary for the ITB problem to disappear. Once you are at that seat height, make a judgement as to whether one leg feels more ‘cramped’ than the other. I would expect you to say that the right side does. If so, shim the left shoe by 3mm and raise the seat height by 3mm. Reassess. If the right still feels underdone, add another 3mm shim to the left shoe and raise the seat another 3mm. I cannot be certain but think it likely that you will find a seat height and left side shim combination that will alleviate your RH ITB problem. I will just about bet that will be a lower seat height than you ride now. If it feels too low once you find that injury free height; don’t worry, as the chances are that after riding that height for 3 weeks at low to moderate intensity and learning a new motor pattern, it will no longer feel low and will be an effective seat height. Of course all of this is supposition based on playing the odds of likely occurrences. Let me know what happens.

      I cannot stress enough that the most common challenge I see to client’s positions is a seat height that they cannot cope with under load. The great majority of riders sit too high (unless they are very tall in which case most sit too low because they are often sold bikes that are too small for them).

  36. Dear Mr. Hogg,
    Thanks for your wonderful blog and oustanding information. It is very kind of you to share information that helps people to find pain free and efficient cycling positions.
    My question is in regards to this post on shimming. I was wondering if you could clarify some ways to gauge whether the right amount of shim has been achieved? There are so many varying guidelines as to how much to shim, but for somebody who really wants to get it perfect, how can you tell? Small differences from day to day in how I sit on the bike or how stiff I am, seem to make the shim feel perfect some days and painful on others.
    I have taken the points you have already posted regarding the 3mm saddle height drops, and having someone else visualize the motion of the posterior superior iliac spines to look for either rotations in the pelvis or asymmetric dips.
    Using myself as an example of this problem of finding the shim endpoint–I have an approximately 1.5cm lld measured by a physical therapist, (unfortunately not by xray) stated to be mostly anatomic. This is corrected during the day by a 1cm heel lift under my right shoe orthotic. The lld mostly comes from my right tibia, not femur, but I believe that this accounts for part and not all of the difference based on many repeat measurements.
    Six months ago, upon first discovering the LLD, I shimmed this difference with 6mm (2 speedplay plates). It felt like too much, but the pelvis looked square on the bike. Recently, by reading your post on the hidden LLD, I finally discovered that my right side was hurting again, because of too little shim, not too much! So, another was added for a total of 9mm. Pelvis looks good, pain is much better. However, I still don’t know whether I’ve achieved the ideal fit. I know it is quite close as the bike feels good. This is why I turn to you because I believe that only the best can further fine tune my close but not perfect fit.
    Also, can you suggest one of your products that would enable, if necessary, a shim of less than 3mm increments? Adding a 4th speedplay shim was definitely detrimental when I tried it.

    1. G’day Andrew,
      You’re welcome. Doing this stuff clears head space for me and is my ‘advertising’ for want of a better description. I don’t claim to know everything but I think the bike industry as a whole takes too little interest in the most important task it can be involved in – ensuring the rider has the best chance to enjoy their bike by being fitted well. And what interest there is is too often compromised (to quote a mail in my inbox from the U.S. “It became clear to me that the ‘bike industry’ accepted fit methodology was nothing but smoke and mirrors”) by the triumph of marketing over reality. I’ve spent a long time working on a money back if not happy basis. So empirically, the methods I post about are well tested. Anyway, I digress. To your problem.

      The only solution open to you that is valid is trial and error. There is no general ‘rule’ of thumb that works for largish LLD’s. No matter what you do, you will never feel as though you have two legs functioning the same way but you want them to be as close to that ideal as possible. What I would suggest is to start keeping a diary. Note down every ride, weather conditions, intensity and duration of ride, size of shim stack and subjective feeling of how you went. Experiment with shim stack height (and how much more rearward you move the shimmed cleat to minimise rocking torque) and after a month or two, you should be able to make a judgement from re reading your diary entries. Give it a try.

      Re your last question. Yes, we manufacture shims in 2 and 3mm thickness’s for all road pedal systems including Speedplay.

  37. Hi steve, are there circumstances where you will move the cleat forward to compensate for a shorter femur, or are you not a fan of this due to it creating instability?


    1. G’day Paul,
      I would never say ‘never’ but a shim is far and away the best method to address a leg length difference. The last time I moved a cleat forward on the shorter legged side to help address a leg length difference was for a client who had had polio as a child. That left him with a 50mm shorter right leg and 5 shoe sizes difference in foot size. In that case I was pulling as many rabbits out of the hat as possible because he had so little ability to control that leg that he couldn’t cope with any shim stack above 10mm. So he ended up with different length cranks, radically different cleat position and a 10mm shim stack. It was the right solution in his case because it worked in the sense that chronic back pain disappeared.

      What is the difference in your femur lengths and how was that difference determined?

  38. Hi Steve, do you have a simple method of working out if you have a leg length problem?
    I have been chasing a lower back problem for a year ( I get a cold type pain in the lower right back after say 40km hard riding), but have a feeling it is linked to leg length?? as I get tight in the right shoulder blade and right ITB also…. ideas?

    I have been fitted very well in Adelaide by Steve Nash @ corsa cycle centre, and have also been seeing a chiro for about 6 months with not too much to say of improvement….

    It doesnt seem to be a big issue, as I still can ride the distance, but it would be nice to do it pain free!!!



    1. G’day Ben,
      they’re are simple methods but I don’t find them reliable. I’m going to write a post on determining leg length differences in the next couple of weeks.

      In the meantime, contact Eric or David Pierotti on 08 8362 9077. They are exceptional.

      Lastly, an ITB problem on the bike almost always means that you are dropping the opposite hip. That would fit, as if you are dropping the left hip, you will twist the pelvis forward on that side. In turn that stretches the right side of the torso out (shoulder blade pain) and loads the right side of your lower back.

      Was this issue tackled during your fit?

  39. In the post about moving cleat 1mm further back from every 5mm of shim stack…what do you do it both cleats are already all the way back? Should I move the cleat without the shim stack 1mm further forward therefore making the shims stack cleat 1mm further back? Please let me know. Thanks so much, as always.


    1. G’day Marc,
      If the shim stack you are using is only 5mm, I wouldn’t worry about it. If it is more than that, I would worry about it. What pedals are you using?

      It might be time to change to Speedplay and use the extender plate kit; part no. 13330. They will allow up to 14mm more rearward adjustment than the standard Speedplay baseplate.

      1. My shim stack is 8mm and I actually have my pedals set up with the speedplay extendor kit all the way back…what do you think I should do? Please let me know.

        Marc Howe

      2. G’day Marc,
        First, take the easy option and leave as is. Does the shimmed foot feel as solid on the pedal under load as the non shimmed foot, both on and off the seat?

        If yes, then you’re fine. If no, the only option left to you is to get hold of shoes with more rearward cleat adjustment potential. At the moment, Giro have the most rearward cleat adjustment positioning with the cleat mounting holes being 10 – 11mm further back than Sidi.

        Failing that, custom shoes are the only option left.

  40. Steve,

    The shim “shorter leg” is actually the better feeling foot…the “stronger” leg. The left side is the one with problems. I feel pressure loaded up on the inside and I believe it is because I have adapted to this short leg syndrome and therefore my left arch has been collapsing/leaning in to make up for this short leg. If my left foot is loaded up on the inside, I would need a valgus wedge even though I was measure with a FFMD with mild varus?

    1. G’day Marc,
      Before doing anything with the left foot, make sure that you aren’t dropping the right hip. Dropping the right hip would potentially explain everything you are saying about the left leg. I am always suspicious when people have left sided issues because the most common cause is the tendency of around 95% of riders to favour the right side. Have a look at The Right Side Bias post and have someone check you on a trainer and make sure that you are not doing what the video clips there show.

      If you are let me know.

      1. When looking between my legs there is more of me off to the right side of the saddle and the left legs is spaced less close to the bike than the right side. I was told when viewed from the front that I was leading with my left hip… but today when I looked down at my legs my left leg is closer to the bike than the right side.

      2. G’day Marc,
        So you’re sitting off centre to the right and having problems
        on the left side. Not surprising and common. The challenge for you is to find out why you are having problems on the right and the address them. Contact me via the Contact section of the site, tell me where you live and I’ll try and point you at someone who can sort out your functional symmetry.

  41. Hi Steve,

    After doing the balance test, my fit is pretty much perfect. Thank you. The ONLY issue I am having, is a little achilles discomfort on my right foot. Not during, but after the ride. Granted, I usually forget to stretch my achilles but stretch everything else.

    When I am pedaling, I can actually look down and see myself ankling the pedal stroke with this foot. This leads me to believe that the right leg may be shorter than the left? And the ankling is a result of reaching for the pedal with the right foot.

    So I guess my saddle height is adjusted properly (for the longer left leg). Am I on the right track here? What can I do to the shorter leg? Maybe shims? Problem is, I am not sure how many mm I may need, or if there is a discrepancy at all. Any advice is greatly appreciated.


    1. G’day Darrell,
      yes, the extra ankling on the right may be a well disguised shorter right leg. That is one explanation. Before assuming that though, get the bike on the trainer, strip to the waist and and take a short video clip of yourself with your camera with whoever is taking the film situated behind and slightly above you. It is a good idea to place a marker pen dot somewhere on your lumbar spine to highlight any movement.

      Doing this will tell you whether there is a short leg alone or whether there is any pelvic movement associated with it. For instance, it is conceivable that you have a shorter left leg and hang to the right which could also explain your your overextending the right leg.

      Let me know what you find.

      1. Thanks I will do that. A few questions about the marker pen dot:

        1. Should I see any movement at all?
        2. What kind of movement would tell me if the right leg is shorter? I assume the dot would be moving to the right?

      2. G’day Darrell,
        Yes, you will see movement. How much and in which direction depends on how functional you are and how symmetrical you are. No, this won’t tell you for certain that you have a short leg. You’ve raised that as a possibility because of lack of symmetry in pedaling technique between left and right sides. The next step is to find out whether you sit squarely on the seat. Very few people do and for instance, if you lean to the left, that would explain the right side ankling; the right leg is being forced to reach further. If you lean to the right, it could very well be because of a short right leg, though there are other possibilities.

  42. Hi Steve,

    I try to figure out the best possible way how to compensate my shorter leg on mountain bike. Any idea from your bike fitting experience how to compensate shorter leg without shims and insoles?

    I use LOOK Quartz MTB pedals with Specialized MTB Shoes. LOOK pedals already come with cleat spacers/shims – 1mm to 3,5mm hight adjustment possible – that are used to optimize the MTB shoe tread and cleat to pedal contact (if there is a gap between the pedal and the MTB shoe tread there is too much play – more clear pictogram explanation see the LOOK hight adjustment instructions page 2 at ). I presume that road cycling shoes do not have any thread and the sole shoe-pedal contact is the cleat, is that right? If I use shims under the cleat of my MTB shoe it will lead to too much play (shoe collapsing to both sides and not staying horizontally on the pedal), which I find negative for leg movement stability.

    I put an extra insole in my shorter leg’s shoe (2mm thick), I tried it and after 2hours ride didn’t notice any discomfort (my feet are skinny and I had sufficient space for extra 2mm insole but not much more and my leg need some shimming).

    Thanks in advance!


    1. G’day Dusan,
      the only way to effectively shim a mountain bike cleat more than 3mm is to have a bootmaker remove the sole and fit a full length dense EVA foam build up of what ever height is required between the sole and the shoe upper and then reglue the lot back together. Done properly it looks like it came from the factory like that.

      However, it is not possible to do this on a shoe where the sole is rubber coated and molds up around the upper as many mtb shoes do. You will need a shoe with a completely separate sole and upper. Sidi Dragon’s are an example of what I mean. The Dragons and other shoes of similar construction with completely separate soles will work fine.

  43. Hi Steve
    Question for the benefit of those needing thin 2-3mm shims….
    Assuming there is plenty of room inside the cycling shoe how do you feel about using one extra Shimano/etc insole (2-3mm thick insole) instead of 2-3mm cleat-based shim?? And also – is it better to use complete 2-3mm thick insole as a shim (forefoot and heel) or to cut the forefoot part of the insole and put it above the cleat area under the shoe insole?
    Many thanks!

    1. G’day Yuri,
      A second insole is okay but under load and compressed, almost certainly it won’t add up to 2 – 3mm. I prefer cleat shims as they don’t compromise fit inside shoe. Which is why we manufacture them However, to answer your question, if it must be done inside the shoe, and there are occasions where this is the case, cut out a shape in 2 or 3mm thick rubber available from a rubber store using the shoe insole as a template. Then cut off the ‘toes’ off the rubber ‘insole’leaving enough length to support the entire foot from heel to the front edge of the MTP joints (base knuckles of toes). Place that under your insole and job done.

      1. Hi Steve, can you advise
        me on the following:
        When I ride the bike I do not
        sit square on the saddle,
        I tend to hang off to the left
        left a fair bit with the result
        lower right hand side of my
        back gets sore and tight.
        Do you think fitting shims
        to my left shoe would help
        correct my position on
        the saddle in any way?
        Kind regards…Ray

      2. G’day Ray,
        Maybe. It depends on the root cause of the problem. Hanging to one side of the seat can be as simple as having a leg length difference, or a seat set to too high. It can also be as complex as large differences in function between left and right sides or a pattern of cerebellar hemispheric motor control dominance.

        Basically you need to find out what the problem is. I would suggest seeing a good chiropractor, physiotherapist, osteopath or functional trainer and have them assess you globally. That will give you the knowledge as to whether there is a bone length difference or functional or structural asymmetries that perhaps can be addressed in other ways.

        If there is a bone length difference or long term structural asymmetries, then yes, a shim stack of the right size can help a lot.

  44. Hi Steve. A curiosity question. In your blog entry on Wedge you provided some interesting statistics on how many wedges your ‘patients’ needed on left and right leg. If it’s not a trade secret can you please share the shim thickness statistics also? In percentage terms how many riders are 2-3mm? 4-5mm? 6-7mm? 9-10mm? 11mm+ ? As you may recall I ride with a 6.5-7mm shim (Speedplay, 2 of their black 3.5mm shims) and I am curious to know where I fit statistically speaking and what percentage of riders need even thicker shims.
    Thanks in advance.

    1. G’day Yuri,
      While I keep individual statistics on shim use, I don’t collate info of the type you’re asking for. Most people who need a shim need 5mm or less which is why our Starter Pack is a 2 and a 3mm. It is uncommon for me to see anyone who needs more than 10mm though it happens. Again I see enough to have bothered making the Leg Length Compensator as I wanted to cover all the traps that go with using a large shim stack; i.e 10mm plus. A high percentage of clients seek our help because they have an issue so I probably see a skewed proportion of the population. Many are like you in that they have not known they had a bone length difference until they get to us.

  45. Steve,
    Should the shim stack be the same measurement to that of the measure leg length difference or is there a window of how close it needs to be to that difference? For example, if there is a measured (via X-ray) leg length discrepancy of 8mm, would the shim stack need to be 8mm as well? Or does it vary because of how one sits and has come to compensate for that short leg throughout their life?


    1. G’day Al,
      The only answer is an individual one. To explain – if the leg
      length difference is in the femur, which never really points vertically while ever the rider is seated, then the compensation only needs to be partial. What percentage always has individual variation. If the difference is in the lower limb, which stays much closer to vertical throughout the pedal stroke, then there needs to be full compensation or very close to it.
      In addition, there is the functional component. If the rider doesn’t sit squarely on the seat OR if the rider is significantly tighter in the lower back, gluteals and hamstrings on one side than the other (which can often be the case with an LLD) then that will add or subtract a functional component to the size of shim necessary. I have seen people with an obvious LLD who were tighter on the shorter legged side, longer legged side and no real difference, meaning a shim stack height is best assessed on an individual basis. If you have access to torque analysis, that can also help determine which is best if there is any doubt in your mind.

  46. Steve,

    Over time, by using perceived discomfort and a powermeter during the last 1/3 of a long training session I’ve fine tuned my Frankenstein stack of shims and wedges to something that seems to work rather well.

    After taking time to do this on the bike, wouldn’t it be a good idea to do something similar for your regular day to day shoes too? If you need 10mm+ on the bike then chances are that and additional amount under the same leg when off the bike would help too, no… Or am I just barking up the wrong tree with only only functionally correct length leg to stand on? 😉


    1. This is a very good question Mark. I’m a firm believer that a rider can only function as well on the bike as they function off the bike. In your shoes the first thing I would do is have an x ray or scan to determine if there is a bone length discrepancy. If there is, I would be suggesting that you gradually use a heel lift or a built up shoe to offset the effects of that in walking gait an allow you to be more functionally symmetrical.

      If there is no bone length difference, then I would start a quality stretching and / or functional exercise regime to address the functional asymmetry. Doing one or both cannot but help you to become a better bike rider.

  47. Steve,
    How does one tell is they are becoming more functional to a point of reducing their shim stack? I have not changed seat height or set back or anything to effect the way my legs feel, but lately I have begun to feel less fluid on the left leg. I have a 7mm shim stack on the right leg because I was measured with an X-Ray to have a short right leg. I have been stretching more (as my left side was tighter which contributed to my short right leg) so I am wondering if the stretching could have caused me to become a little more functional. Would too much of a shim stack make you feel not fluid in both legs? I used to feel strong with both legs and the latter part of the season I feel uneven. Thanks

    1. This is a tough one but not uncommon. Firstly, how do you tell if you are more functional? Only you can answer that as the signs vary for everybody. If you know that you are more flexible in particular areas or the entire body, then it is likely that changes to your bike position need to accommodate that.

      Your situation is that you have a 7mm shim on the right which used to feel okay and allow both legs to feel ‘even’. Now, with improved flexibility on the left side, the left leg feels worse. Seeing as it is not the shimmed leg that feels worse, it is unlikely (though possible) that the shim stack is too high. What is more likely is that the change in function over time has caused a change in technique.

      For instance, if you are dropping your heel more now, that will increase leg extension and as I’m constantly saying, any challenge to position evokes an asymmetric response. If your left leg feels ‘ordinary’, drop your seat 5mm and see if that is an improvement. Depending on what you find, you can reassess and drop more or move back to original position.

      The other common issue is that if you are more functional to any degree, and assuming you had good foot correction in form of arch support and wedges, the improvement in function may indicate that foot correction needs revisiting.

      I would suggest going through all the posts on position starting with Seat Height and Seat Setback and then moving on to the Foot Correction series. That exercise will allow you determine what to change and by what degree. While this process is going on, make sure you read and follow the instruction in How To Avoid Bike Fit Hell.

  48. Steve,
    I visited a chiro and he took and X-ray of me standing (legs locked) and my pelvis was tilted down on the right side by 8mm…so he therefore said I theoretically had a short right leg. I have been experimenting with shim stacks and since he told me I had a short right leg (of 8mm) I have been riding with a 7mm (two 3’s and a 2mm) shim stack. But while the right leg (the so called short leg) feel fluid and powerful, the left leg does not feel as fluid and powerful. I was wondering if I have maybe overdone or underdone the shim stack, or even if I need one? I have level 2 arch support with ESoles and have checked and rechecked saddle height and seat set back from your tests so I know those are right…and that is why I think it has to do with the shim stack? Should I try removing the stack and starting over?

    1. G’day Chris,
      If the left leg feels less powerful, then you are still
      favouring the right leg. I know you’ve shimmed it but a lengthy period of riding without compensation for a short leg (and a lifetime of walking around with it) will have caused asymmetric changes in the way that you function in the hips and lower back. What your story illustrates is that the root cause of your problem, now that the leg length disparity has been compensated for is those asymmetries of hip and lower back function.

      Here’s a To Do list:

      1. Have a look at this, assess yourself and see what you fail.

      2. Buy the book Athletic Body in Balance and start work on the corrective exercises.

      3. Re the bike – start with a smaller shim stack and experiment keeping the advice in the How To Avoid Bike Fit Hell post in the forefront of your thinking.

      4. Recheck your seat height. If even a tiny bit too high, it will reinforce your already strong tendency to self protect the right side at the cost of the left.

      5. Re Foot Correction part 2 – Wedging and experiment with that. If you
      have an 8mm leg length difference, I’ll all but guarantee that you need
      wedging and almost certainly different numbers on each side.

      Let me know what happens. And take your time with what I’ve suggested above.

      1. Steve,
        I feel that I am tighter on the left side (the longer leg) particularly in the piriformis and psoas. I am not sure if this is from an adaptation from living with a short leg. But I definitely think that I need more wedging and arch support on the left (I think this is from tilting to the short side my life while walking). So just because I have a 8mm LLD it doesn’t necessarily mean 8mm shim stack? I will need a shim stack but just one that makes both legs feel fluid? Thanks

      2. Correct. The right shim stack is the one that allows you to feel more even. However, if 8mm is too high and you feel awkward on the left, that means that you are still dropping or favouring the right side, even is shimmed to much. That is why I’m suggesting you investigate your global movement patterns.

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