Pedal float and SPD cleats

I had been using Shimano M520 SPD pedals for a while and they have 5° of float. I wanted to try something with a bigger platform, so I swapped on Shimano XT PD8120 yesterday before a 2 hour trainer ride. Those have 4° of float, and I had some unexpected, slight knee pain and it seemed hard getting my foot in a comfy spot without a bit of discomfort in my lower, right leg. This is with the same shoes/cleats (SM51)

Can 1° of float make a difference? It’s possible I’m crazy too :crazy_face: just trying to figure out if I should swap back, or if there’s another solution.

Are there SPD pedals worth looking at with a bit more float?

Its possible that the 1deg less float may have an effect, but if its a different pedal, I would consider the Q factor. Do you know what the Q factor difference (if any) is?
Good luck in your search for a solution!

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I thought the float was a property of the cleats?


@mrpedro It is for road pedals, but each SPD pedal included a float value in the details when I was looking at them.

@Quinncube I didn’t check…great point! I’ll see what I can find.


Maybe you need to set your cleats up with a little more twist, if you have to go right to the limit of the float to find a comfortable position. The float should really just allow for movement.

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I suppose it is theoretically possible that the 5deg facilitated enough movement just for a fit that was right on the edge and that loss of 1deg pushed you over it. Perhaps the stack heights of your new pedals are also slightly different @FrankTuna compounded the issue. I would guess a good fitter would see you right with the 4deg pedals.

IMC before I had my leg length issue diagnosed when my BB bearings started to fail that 1mm of extra movement would cause me to have hip pain. I think my set up at the time was too close to the edge of being wrong, that a very tiny change would push me over it.

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Yeah, AFAIK, float angle limits are a property of the cleats.

What might be the difference here is a “newness” of the other pedals, and of course the spring tension. Either or both of those could lead to a difference in feel between any pedals (even the identical model).

If you happen to be on a cleat alignment in your shoe what is borderline, a tighter and/or newer setup might show a problem where an older worn or lower tension setup might mask it.

I also need to search, but fully expect Q-Factor to be identical.


Thanks Chad (and everyone else) for the help!! I can’t find the 5 degree link I saw earlier, but I was going by the pedal descriptions. They come with cleats so maybe that wasn’t clear to me at first that the float was related to the pedal! I’ll see if I can get the tension to match on the pedals.

I’ve had 2 bike fits, both times with SPD cleats (though both times I had M520 pedals). Both fits put my cleats in different places and have given me different seat heights :upside_down_face: My right foot angles out a bit at the toes when walking, my left is straight. I asked both fitters if my right cleat should be angled a bit to account for this, and both said the cleats should have enough float to take that into account. I’ll play with cleat angle a bit and see if that helps.


  • Cleat angle is sometimes tricky. I have large toe out condition on both feet in normal life, and have to match that in my bike setup or I have knee issues in short order.

  • Depending on the amount of toe out you have, it is worth trying to mimic that in your cleat setup. That is my default starting point for any new rider. Then I adjust as needed from there.

  • That’s because what we see in the rider off the bike and on the bike can sometimes vary. I’ve had customers with notable toe out in the seated look, but we ended up with dead straight cleats because that is what felt best to them.

Short story, test a bit and see what feels best.

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How your shoes interact with the pedals can also affect the float. Bigger platforms may be holding your feet in a more fixed position in certain parts of the revolution


Yup, I meant to cover that. The wider platform may be grabbing the shoe more than the minimal pedal design, and adding to resistance or even limiting float travel.


Yep, as someone who switches between small and large platform SPDs on a regular basis you can feel the difference, can’t say definitively the change in float but there is progressive resistance even with relatively minimal soled cyclocross shoes


Interesting…this didn’t even occur to me! Do you think it’s worth using the different pedals, or maybe it’s just easier to stick with M520/M540’s on all my bikes? I have pretty stiff shoes, but thought the extra platform might feel a little more “connected” if that makes sense. That could all be in my head too!

In my use case the bigger platform isn’t really there for support, but rather a bigger platform so I can pedal easier if I miss the clip in on my commuter since I’m taking off from lots of lights and stop signs. With stiff shoes I like smaller platforms and I race on small platform SPD M8000s

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Did you check your saddle height?

The pedals are slightly different thicknesses.