Switching from Speedplay to SPD-SL: Extra Leg Fatigue

[KS59]

Recently, I switched from Speedplay to SPD-SL pedals. While I really like the locked in feeling of the shimanos, I've noticed that my legs fatigue much more quickly compared to speedplays. For example, after my group ride this past weekend, it felt like I had just finished a 100 mile ride, when in reality it was only 60 miles. My knees felt fine (better than when on speedplays) so it's not like the cleats are in the wrong position. Maybe since I feel more locked in I'm grinding a bigger gear? Plus I like that the fact the the shimano pedals are much more simple than the speedplays.

Anyone know what could be causing this extra leg fatigue?

[jekyll man]

Not adjusted the seat height to compensate for the extra stack of the shimano pedals?
Have you changed shoes as well?

[KS59]

Yes, I accounted for the difference in stack height and changed my saddle height accordingly. I used the same shoes as well.

I'm thinking it has something to do with the tighter float, just can't figure out why that would make my legs more fatigued.

[doogie2304]

which shimano cleats are you using?

[KS59]

The Yellow Cleats with 6 degrees of float

[11.4]

You are changing shoes and cleats/pedals. This is quite a bit if all the dimensions are still corrected precisely. I suspect you might also have a slight difference in cleat orientation, fore- or aft- alignment, or Q-factor. It doesn't take much to tighten up your legs and cause you to feel extra fatigue. Throw in the rather different stability going from a Speedplay to an SPD-SL, and there's a lot that your legs have to readjust to. I wouldn't worry yet. Just ride and it'll feel better.

[tommasini]

I gotta add that I love the "locked in" feeling too. And in my case I go with fixed cleats (and wide platform pedals). I can say that as I don't have knee/alignment issues. Its a super feeling to sense being firmly connected to the bike in all directions during power situations. So I'm not trying to go to far off topic but just chiming in that if you can keep your joints happy with a "locked in" feeling then I highly recommend going that direction.

For the OP's issue, I'll only guess that maybe despite thinking you've got the saddle height and cleat fore/aft/in/out placement spot on, that perhaps it's not just exactly like before. Maybe reacquaint one shoe back with the prior cleat/pedal - not to ride (different stack height) but to see how the shoe lines up (left/right/angle/fore/aft) with the spindle/crank, or other reference point compared to the other.

[maxxevv]

The fore and aft position on the Shimano cleats are a little different compared to SP ones.

Usually if the shoes are the same and saddle has been compensated for and you do not feel any discomfort on the knees, its all down to the fore and aft position of the cleats.

Try exploring that.

[KS59]

Thanks for all the input guys. I'll start messing with cleat placement and hopefully get it figured out.

[964Cup]

Have you looked at any video of your riding? Might be an idea to ride with Speedplays, and then with SPD-SL, with a buddy filming you from behind - look at your feet, ankles and knees to see if you were using the extra float in the Speedplays to absorb any eccentric motion in your pedalling action. The resistance of the SPD-SLs at the limits of their float will stop you pedalling in the same style if this is the case, and that might be tiring you out.

[Rick]

I have been back and forth between Shimano and Speedplay a couple times.
So I am just speculating here, based on my feelings, but maybe some validity:

In the Speedplays, the foot angle is really floating all the way around, so you don't even notice small changes, you are really "floating".

On the Shimano, even the yellow cleat does not really "float", it just has "ability to move". So if your foot angle wants to move, you feel it, and perhaps tighten your muscles slightly to resist it or correct it. So it might help to very consciously relax the feet/legs more on the Shimano. I think this is what I did. Then, going back to speedplays I had the opposite problem: my legs felt like they were flying all over the place and I had to relax and ignore the slight wiggles. Luckily my legs adapted to either of the pedals. I have stuck with Shimano because they are slighly more bullet-proof and maintenance free.

On the other hand, maybe your leg biodynamics is such that you really do need the extra light float of speedplays, and tighter pedals will always be more fatiguing. Only you could be the final judge of that. Take careful note if the relaxation technique doesn't work and if you start getting any pains from the Shimanos.