Bike Fitting at Loue Bicycles - Using Pedal Stack Height to replace Cleat Shims

In the previous bike fitting posts at LOUE Bicycles, I wrote about how there is a need to add shims on the SPD cleats of my shoes, due to the slightly different leg length caused by my swiveling hips during pedaling.

A recommended addition of 1.5 mm was suggested for the left leg, to adjust the leg reach slightly to match the right leg. A 1.5 mm difference is actually quite small, compared to the overall length of the leg. On my road bike, the Focus Paralane which I used for the actual bike fitting, I will try to achieve the ideal bike fit to optimize the power output and pedaling comfort.

Bike fitting on the Focus Paralane, at LOUE Bicycles.

As for the other bikes, such as the folding bikes, it is not so critical, as I will be pedaling leisurely instead of at high power. I will probably switch between flat soled shoes or SPD shoes occasionally, on the dual sided SPD/platform pedals.

I have an idea to adjust the leg length, but not by adjusting the shim on the SPD cleats. Instead, I can use pedals of different stack height, which would have the same effect. If the pedal has a taller stack height (distance from centre of pedal axle to sole of the shoe), it will effectively shorten the distance from the saddle, which has the same effect as adding a shim on the SPD cleat under the shoe.

Measuring the pedal stack height is not easy, as it is difficult to find the centre of the pedal axle. Therefore, to simplify the measurement, I used the pedal thickness instead. Then, I assume that the stack height is just half of the pedal thickness. There might be some inaccuracy here, but I think this is good enough.

The idea is to use a pedal with a taller stack height (thicker) on the left crankarm, and a pedal with a lower stack height (thinner) on the right crankarm. This effectively gives a left leg reach that is shorter, which suits my purpose.

I tried to use the product spec provided by Shimano for the pedal stack height, but it doesn't match what I measure (thickness). I think the difference is what I mentioned above, that the actual stack height is measured from the centre of the pedal axle (virtual point) to the sole of the shoe (another virtual point). I can't measure those points directly or easily, which is why I chose to measure pedal thickness instead.

Moving forward, I will use pedal thickness to approximate the different stack height of the pedals that I have, to find a suitable pedal for the left and right side.

The pedal that is currently on the Focus Paralane is the XTR PD-M9020, which is rather lightweight.

I have an alternative SPD pedal, the new GRX PD-ME700 SPD pedals, which are similar in design to the other trail SPD pedals, but at a lower price point.

I know that the XTR pedal has the lowest stack height, so this will remain on the right side, while I will find a thicker pedal on the left side to reduce the leg reach.

Thickness of XTR PD-M9020 is 17 mm.

Here is the GRX PD-ME700 SPD trail pedals. I will do a separate introduction/comparison post later on.

Thickness of GRX PD-ME700 is 18.7 mm.

From these measurements, we see that between XTR and GRX pedals, there is a 1.7 mm difference in thickness, which works out to about 0.85 mm difference in stack height, theoretically. It is not as much as the 1.5 mm that I was advised to use, but I think it is acceptable, and better than nothing.

Installed the ME700 pedals on the left side of the Focus Paralane.

There is a bigger gap between the spring and the cleat platform on the ME700 pedals on the right side of the picture, versus the XTR pedals on the left of the picture.

Later on, I remembered that I actually have another pair of SPD trail pedals, the Deore XT PD-M8020 which is currently in use on the Cervelo Aspero gravel bike. For a comparison between XTR PD-M9020 and Deore XT PD-M8020 pedals, check out this comparison post.

Deore XT PD-M8020 SPD trail pedals

The M8020 pedals is actually slightly thicker than the ME700 pedals, at 18.8 mm.

With that, I swapped the pedals again, by installing the left side M8020 pedals on the Focus Paralane, and retaining the XTR M9020 pedal on the right side. This gives me a stack height difference of 0.9 mm, which is frankly a small amount.

Can I actually feel this small difference? I am not sure, but I will try it and see since I have the pedals to swap around.

XTR vs Deore XT pedals side by side

There is a small difference in stack height and thickness between these two pedals. I will follow the bike fitting advice to adjust the leg reach.

In the end, I used pedals of different stack height to account for the different leg reach, instead of adding shims under the SPD cleats. Although this means that the pedals on the left and right side don't match, I think it is a more elegant solution than adding shims under the cleats, which comes with other problems.

I think I will only do this pedal stack offset on my Focus Paralane and the Cervelo Aspero, since these two bikes are more sensitive to a bike fit. As for the other bikes, they are ridden more casually with casual shoes, and I don't think a small stack height difference actually matters.

I am glad I did the bike fit at LOUE Bicycles, as I really learnt a lot about myself and also the bike. It will be great to replicate the bike fit on other bikes with the data generated, instead of adjusting it bit by bit using trial and error.

Bike Fitting at Loue Bicycles - Cleat Shims

Continuing from the bike fitting session at Loue Bicycles, another area that was adjusted was the height of the cleats.

Other than shifting the cleats rearwards by about 20 mm, Timothy also added a shim on the left side SPD cleat. Due to the body asymmetry described in the previous post, the saddle height was finally set to be optimum based on my right leg, but this means that the saddle height is slightly too high for my left leg.

Therefore, to compensate for this, a cleat shim was added under the left side SPD cleat, in order to effectively lengthen the left leg slightly. 

Plastic SPD cleat shims added temporarily by Timothy. By stacking 2 pieces, it effectively adds about 1.5 mm of height.

The plastic shims are just a temporary measure, as they do not last long. He recommended that I get the Crankbrothers shoe shields, which are metal shims that will work better.

Crankbrothers shoe shields! 

These are actually to protect carbon soles on the shoes, or to push out the cleats on shoes where the tread protrudes too much.

The shoe shields go between the cleat and shoe.

Each pack comes with 2, for a pair of shoes.

The knurled surface on the stainless steel plates will be on the side of the shoe.

Each shim has a thickness of 0.8 mm.

I plan to use 2 shims, to get a thickness of 1.6 mm, which is close to the 1.5 mm suggested by Timothy.

However, 2 shims is too much, as the cleat bolts are not long enough to engage the thread properly.

In the end I only added 1 shim, under the left cleat to increase the height by 0.8 mm.

However, this additional 0.8 mm shim made the cleat protrude above the treads of the shoe, as you can see on the right side of the picture.

After I already bought the cleat shims, I realized that SPD cleats sometimes come with its own shim, I had forgotten about that. This is how it looks like.

This fits onto the SPD cleat and adds about 1 mm of thickness. It is usually used for non-Shimano shoes where the sole treads may be too tall for easy pedal engagement.

Same here, the shim makes the cleat protrude from the sole treads.

Although the taller cleat is necessary to compensate for the leg length, the cleat keeps touching the ground when I walk, since it protrudes too much. It is very annoying as I can feel the metal cleat clicking on the hard ground, and it is also slippery due to the metal cleat surface.

I will have to think of an alternative solution as the protruding cleat is not acceptable for me.

A side effect of moving the cleat rearwards, is that the shoe is effectively moved forward. This leads to shoe interference with the front wheel during cornering. As the Focus Paralane already has mudguards, which were already touching the shoe previously, this cleat adjustment made it even worse.

Interference between the shoe and the front wheel/mudguards during cornering.

Due to this phenomenon, I have to be extra careful during cornering, so that the shoe is not pointed forward where it can touch the mudguards. It is avoidable with careful placement of the pedal position during cornering (outside shoe downwards, inside shoe upwards).

In summary, the cleat shims can effectively extend the leg reach, but it causes another problem where the metal cleat keeps touching the ground during walking. I have an idea to solve this, which will be shared in the next post.

Bike Fitting at Loue Bicycles - Insole

Another area that Timothy from Loue Bicycles suggested I improve on during the bike fit would be the insole of the cycling shoes.

I have been using the RX8 gravel shoes since it was first launched in silver camo colour, and I liked it so much that now I have another pair in Cactus Berry colour. It is basically the best lightweight SPD shoe that you can get for road cycling or gravel riding.

So far I have been using the stock insoles, as I don't have any foot arch problems as far as I know. This means that I have been using the mid height insole that came with the RX8 shoes.

Timothy recommended that I get Sidas sole inserts to improve the support for my foot during pedaling. This will stabilize my foot during pedaling as he noticed that my foot was rocking from side to side during harder efforts. Before that, I decided to try the high insole that was also included with the RX8 shoes.

Stock yellow insert with mid height, and the red colour high insole which was included with the RX8 shoes.

Changed the yellow inserts to the red ones, just by pulling it off the main insole, as it is only attached by velcro.

Based on repeated testing (one side yellow one side red, swap sides, both red, both yellow), I was able to detect a small difference in the support. The thicker red insole was able to support the arch a bit more, but the difference is quite small.

Anyway, this was not the insole that Timothy recommended, which was why I still went to get the Sidas sole inserts that he recommended. The specific model that he recommended is the Sidas mid arch slim, which has a flat profile which is more suited for cycling shoes due to the limited internal space. It is not cheap, but it is worth trying it out to improve the pedaling efficiency.

Based on my brief research, most cycling shoes do not come with adequate support for cycling, as the soles are thin and simple. This aftermarket insole will improve the foot support.

Standard model for mid arch foot, and flat for low volume shoes such as cycling shoes which wrap snugly around the foot.

If you prefer a half sole instead of a full sole, you can cut it in half.

Adds some weight to the shoe, but if the weight is not on the bike, it doesn't count.

L size insole is for a foot size of EU 42-43, which is suitable for me as my EU shoe size is 42.

Sidas insole on the right, looks quite a lot bigger than the original RX8 insole.

The Sidas insole has a taller and larger support area, as can be seen from the larger green foam area.

The stock insole is like a piece of paper, compared to the Sidas insole. Let's hope the Sidas insole works well.

The Sidas insole is wider compared to the stock RX8 insole. I wonder if this would prevent the insole from fitting properly inside the shoe.

Using the heel as the alignment datum, I found that the Sidas insole is slightly larger. I marked the Sidas insole and used a scissors to trim off the difference as recommended.

After trimming the Sidas insole to follow closely to the shape of the original RX8 insole, it was fitted inside the RX8 shoe. It was rather difficult to fit the insole in properly, as the Sidas insole is less flexible due to the larger green foam. Also, there is an elastic band inside the RX8 shoe which also makes it hard to insert the sole properly.

However, I was pleased to find that once the insole is aligned properly, it actually fits pretty well inside the shoe. There were no creases or folds due to an incompatible shape outline.

Sidas insoles installed into the RX8 gravel shoes.

Once again, I tested the insoles systematically to see if it really makes a difference compared to the original insoles.

1) Sidas insole on one side, stock insole on other side

2) Swap sides and test again

3) Try both sides with Sidas insole

4) Try both sides with stock insole

I was able to feel a very big difference between the stock insole and Sidas insole. This was tested on various rides over a week, and the result is that the Sidas insoles really improve the stability of the foot.

With a better insole support, the foot is more stable during pedaling, instead of rolling around during harder efforts. This is a good improvement from the stock insoles. If you feel your foot rocking slightly from left to right, you may want to try a better insole to see if it helps to stabilize your foot.

Considering that there are thousands of pedaling strokes during a ride, it makes a lot of sense to consider the shoe and foot stability as well in order to maximize pedaling efficiency and comfort.

Bike Fitting at Loue Bicycles - Initial Fitting

Although I have been riding bikes for quite a number of years now, I have never gone for a proper bike fit. I have always adjusted my bikes based on my feeling and advice from experienced cyclists. So far it has worked pretty well, with the handlebar and saddle positions more or less optimum.

However, on faster or longer rides, I will tend to feel uncomfortable, as if some setting is wrong. The hamstrings or calves will feel stretched, even though the saddle is not too high. Generally it is OK to ride but I just feel like it is not optimized.

That is why I decided to go for a proper bike fit, to see what is the issue. A better position will improve the efficiency of my cycling, more than any equipment upgrade. Based on recommendations, I went to Timothy of Loue Bicycles for a Classic Dynamic Bike Fit.

There is a 3 month waiting time, so I had to wait patiently after booking a bike fit session. Apparently each bike fit takes quite a few hours, so there is only a limited number of bike fits that can be done each day.

The day has arrived! Loue Bicycles is located just above the F45 gym at 11A Lichfield Road.

Brought my Focus Paralane road bike there, to get it fitted properly for road riding. Removed all the accessories to make it easier for adjustments.

Here we are!

With the bare minimum components necessary, even the mudguards have been removed.

I have never gone for a bike fit before, so I was not sure what to expect. Before I started pedaling on the bike trainer, Timothy started by analyzing my body posture and balance while barefooted. This will help to find any issues with flexibility or motion limitations.

Since I was using MTB SPD cleats, he also reset the cleat position to a more efficient and stable location.

Apparently my cleat position was too far forward, which can lead to ankle instability and calf strain during hard pedaling. A better position is to place the cleat slightly behind the joint of the big toe, which will improve the pedaling stability.

To do that, he pasted a tiny magnet on the joint of my big toe, and then I wore my shoe with the magnet attached to my foot. From the outside of the shoe, he used another magnet to locate the magnet on my foot, this transfers the toe joint position to the outside of the shoe.

Then, using markers, he traced the position of my toe joint all the way down to the bottom of the shoe, where the cleat will be fixed.

Using markers to indicate the position of my toe joint, and trace it all the way down to the bottom of the shoe, where the cleat is.

The cleat is set slightly rearward of the toe joint, for better ankle stability and pedaling efficiency.

See how big the difference is! The new position is shown on the left, while my old cleat position is on the right. I think it shifted by almost 20 mm.

Only then did I get on the bike and start pedaling, with the new cleat position.

The new cleat position felt different, as a 20 mm change is very big. However, it felt better, as the ankle is really more stable, due to the shorter distance between the ankle joint and the cleat. To think that I have been cycling with a poor cleat position for such a long time!

The bike trainer is placed on a movable platform, which can swivel 360 degrees. This is because there are cameras at the sides, while the Retul bike fit sensors are on another wall. By swiveling the platform, the cameras and sensors can view and measure all around the bike.

Timothy noticed that while I was pedaling, my right hip was swiveling forward. He actually predicted this earlier, when I did a plank posture on the floor. He noticed that my right hip dipped downwards quite a lot compared to the left side.

True enough, this natural asymmetry of my body causes my right hip to swivel forward on every pedal stroke. When the hip swivels forward, it effectively shortens the distance from the saddle to the pedal. The result is that the saddle height is too low for my right leg, while it is too high for my left leg.

Picture from the rear, showing how my right hip swivels forward on every pedal stroke.

This asymmetry is made worse by the saddle, which he says does not provide me with enough support. I have been using the Selle Italia SLR Kit Carbonio Flow saddle for many years, and I have a titanium rail version of it on my other bikes as well.

Although this saddle shape is nice and are super lightweight, they are not wide enough for me, at just 130 mm wide.

By placing a pressure sensitive mat on my saddle, it can map the pressure points exerted by my sit bones. Here is how it looks like below.

Pressure map on my Selle Italia saddle, with more pressure on the left side compared to the right side.

The saddle pressure points correlates with the observation from the camera, where the right hip swivels forward. Since my saddle height was set (unknowingly) at the mid point between my right leg and left leg reach, it means that the saddle is actually too high up for my left leg. On every pedal stroke, my left leg has to overextend in order to reach the bottom of the pedal stroke, which is why there is higher pressure on the left sit bone. This was the discomfort that I felt, but I could not explain what it was, without the cameras and sensors showing what is going on.

Apparently most people have some degree of asymmetry, so it is quite normal. From his experience, it is difficult to correct body asymmetry, as the body tends to revert back to what it is used to under high load or stress. It is more sustainable to adjust other parts to suit the body asymmetry.

For a start, I need a saddle with better support, which means a wider saddle. Somehow I had already felt that the saddle might be one of the causes of my discomfort, which is why I had already bought a new saddle, but did not fit it on the bike yet.

This is the PRO Stealth Superlight Saddle, which is the lightest version of the Stealth saddle. Everyone I know who has tried the Stealth saddle has high praise for it, which is why I got one as well without even testing it. A separate review of the saddle will be done subsequently after more riding.

PRO Stealth Superlight Saddle, with a monocoque carbon shell integrated with the saddle rails.

Since I had already brought the saddle to the bike fit, Timothy helped to fit it onto the bike, and also adjust the saddle height. After some height and angle adjustments, the saddle pressure was checked again.

This time, the saddle pressure is much more balanced between the left and right side, as shown below. It is amazing how a wider saddle can improve this asymmetry between my left and right pedaling strokes.

With the new PRO Stealth saddle, the saddle pressure is almost equal between the left and right side (right view is with the new PRO Stealth saddle).

Using the side camera to help optimize the saddle height and position. This has to be done before moving on to the handlebar position.

Although the PRO saddle has much better support, it still does not completely solve the asymmetry caused by my right hip rotation during pedaling, as there is still a slight leg length difference. There is another adjustment that Timothy did to the cleat, which I will explain in the next post.

For this bike fit, we started with the cleat positioning, followed by the saddle position. This pedaling platform has to be set correctly before we can move on to the handlebar position.

With the saddle height adjusted, next is to adjust the height and reach of the handlebars. Based on what Timothy sees, the height of the handlebar is OK, but the reach can be longer. I had also bought a longer stem, in anticipation of this issue. It seems like I roughly knew what was wrong with my riding posture, but without an expert analysis, I could not quite highlight the exact issue.

By swapping the stem from 80 mm to 90 mm, the reach is better for road riding. 

PRO PLT Stem, 90 mm long.

So far, the saddle has been changed to a wider one, while the stem has also been changed to a longer one. During handlebar adjustment, he also asked why I used a 38 cm wide handlebar. It was strange as I was sure I was using a 40 cm wide handlebar as I always did.

Upon measurement, we found that although the handlebar is labeled at 40 cm, it is 40 cm wide only at the drops. At the top where the shifter hoods are, it measures about 38.5 cm. There is some flare on the handlebar which explains this difference, which I have never noticed.

I can either keep this slightly narrower handlebar for better aerodynamics, or change to a proper 40 cm handlebar next time. For now, no problem to continue using it.

Finally, after the bike has been adjusted to be optimum for me, it is time to record down the measurements, so that this same measurements can be transferred to other bikes. I thought he was going to measure the dimensions one by one to record them down, but it ended up being much more high tech that I expected.

With the Retul sensors on the wall recording the position of the probe, he started tracing the position of critical points on the bike. Using the probe, he followed the sequence on the screen to trace the required areas on the bike.

For example, to log the centre of the bottom bracket, he inserted the tip of the probe into one of the chain ring bolts, and turned the crank one round to mark the centre of the bottom bracket. Next, he traced the profile of the saddle, and this automatically gives the saddle height relative to the bottom bracket. Other measurements include tracing the shifters to give the handlebar height and reach, etc.

This is basically measuring the entire bike using a Coordinate Measuring Machine (CMM), where the key dimensions of the bike is traced and recorded.

Bike geometry definitions

And this is my bike fit data! All these measurements are automatically calculated based on the probe tracing of the key bike components.

I was very amazed by the CMM measurement of the bike geometry, it is so much easier, faster and accurate than manual measurements. With this data, I can transfer the same setup to another bike for the same bike fit.

Summary of changes:

1) Cleat position shifted rearwards by about 20 mm

2) Saddle width changed from 130 to 142 mm

3) Stem length changed from 80 mm to 90 mm

4) Saddle height adjusted based on new cleat position and saddle

There are other changes, which I will explain more in subsequent posts.

5) To get better insoles with more support for the foot arch

6) Cleat shim added under left cleat

It will take some time to get used to the new bike fit, but it should get better once I ride more in the new posture. The whole session took 3 full hours, 1 on 1 with Timothy. I learnt a lot and now I know the value of a good bike fit. There is no point getting the best bike if you don't fit well on that bike.

To be continued!