SPD vs SPD-SL pedals and stack height, how do you measure?
 

Hi there

I just switched from Shimano's PD-A600 pedals (one-sided SPD road pedals) which I used with Northwave MTB-shoes to the Ultegra 6800 SPD-SL road pedals which I am using with Shimano R171 road shoes. As it's probably normal during the first days with the new pedals and shoes things feel slightly different and I am wondering if I should adjust the saddle height for the different stack height of the pedals. Problem is, I am not sure what the stack height is.

On the web I found a source that said 13.7mm for the Ultegra pedals (did not mention though if it's the 6800 or an earlier model) and 14.3mm for a Ritchey one-sided SPD road pedal which is the closest thing I could find to the PD-A600. Double sided Shimano SPD pedals are listed as 17mm. Then I guess the shoes play a role as well. I would have thought carbon-soles on a road shoe should be thinner than the sole of a non-carbon MTB shoe, right?

So my questions really are the following:

- Is there any information available on the stack height of specific pedal and shoe models?
- If not, is there a semi-reliable way of measuring it?
- Should I even bother, those couple of mm up or down won't make any difference anyway?

Any advice will be very welcome. Thanks!

Lars

SPD SL* goes on Hard sole Road shoes the Pontoons stabilize the cleat on the pedal ..

SPD is another Shimano Standard other companies adopted to Get a market Share .

so others should all be consistant to be compatible ..

We Sold shoes with that* cleat for Spinning classes , since their machines used those pedals MTB and Dual side work too .

Just adjust by feel. I found I was about 5mm higher saddle with SPD & MTB shoes than SPD-SL & road shoes. The problem is that measuring shoes is really difficult, so unless you're planning to use adapters and the same shoes you can't measure the real stack (foot bottom to pedal axis).

yeah, I know both systems very well. As I said, I am just wondering about the differences in stack height between the two...to be honest I am not exactly sure what you trying to say in your post :)

makes sense, I just have a feeling the MTB SPDs are higher than the one-sided ones I have. Well, I guess I really just have to get the allen key out and move the saddle, just not sure if up or down ;)

Sorry cannot Do a full shoe/pedals market survey for you .. good luck..

I just helped customers Buy what is in the store ..

no problem, I certainly did not expect that ;)

SPD-SL is probably half a cm lower, mostly due to the thinner shoes. If you run high end carbon MTB shoes there is not a huge difference.
You are also more likely to want your seat a bit lower on your MTB/cx/commuter with the SPD and MTB shoes, so seat height is about the same at the end of the day

Hi,

I'm sorry I can't help with your question but I was wondering if you had noticed much of a difference (other than the stack height) between using the SPDs and SPD-Ls? In terms of power transfer etc. Thinking of doing the same.

Well, yes I think there is noticeable difference. I had the PD-A600 pedals which are labeled as SPD road pedals and which I found much better in terms of power transfer than the double-sided SPDs I had before. But my new Ultegra SPD-SL are even better. The contact area to the pedal just seems larger, better distributing the pressure you put on the pedal. I also bought shoes with a carbon sole, so that definitely makes a difference in terms of power transfer.

In the end I just left the saddle height as it was and I am totally fine, so did not see any reason to change anything in that respect.