Shimano Mountain SPD Cleat Wedges

2021 06 06: I added a rev 2 folder for the Inventor file & STLs. The improved version better supports the cleat in the rear. I use Shimano SM-SH56 cleats. Since changing out my cleat wedges to these 3 degree versions (rev 1), it certainly feels a lot better pedaling, although the cleat sticks out a lot from the recessed bit in my shoe.

I changed out the bolts to M5 x 0.8 x 12 mm. The standard bolt length is 10 mm IIRC. You'll likely need the extra 2 mm to compensate for the added thickness. You can get these bolts cheaply everywhere. I tried 16 mm bolts & they were far too long; I could feel them poking my foot inside the shoe.

2021 03 28: I ported these models to Inventor. Now with a better printer, I achieved much higher resolution on the layer height. I'm leaving the Solidworks models here for posterity too, but the IPT is better defined in geometry.

I have a 1 & 3 degree version available, both as STLs.

I recently volunteered as a test subject for a practice bike fit. Although I benefitted from the cleat wedges they installed, they cost $20, which is far beyond their manufacturing cost.

So I made these.

1 degree incline, with a thin & thick edge.

There are STLs for a single one, plus a three-wedge assembly.

Never tested. I don't recommend installing these unless you know what you're doing or a qualified bike fitter suggests them. Responsibility is yours if you mess up your joints/body by misusing these.

How I Designed This

Thin edge is 0.40 mm, thick edge is 1 mm. Based on measurements of the BikeFit red SPD cleat wedges.

Here are the originals: https://www.amaincycling.com/bike-fit-systems-cleat-wedges-for-spd-pedals-1220802/p318703

I used the green wedge image as a template for a trace. I scaled it by referencing the slot in the BikeFit red cleat wedges, which came out to be constrained inside a rectangle of 8 mm width by 27 mm length.

I used lines & splines to complete one side, then mirrored the result. Extruded, then cut-extrude to leave behind a 0.40 mm thin edge, then a 1 degree incline to the other side. This left 1.003 mm, which is close enough to 1 mm for me.

The extrusion sketch doesn't actually matter too much as long as the entire cleat is sitting on the edge, which I believe to be the case.

I made the three-wedge assembly because printing 3 separate 1 degree wedges, then stacking them will not give the same angle due to imprecision inherent to 3D printers. I also need them personally.

I maxed out the gauge here (https://www.amazon.com/Bike-Fit-Forefoot-Measuring-Device/dp/B005Z177AA) at around 20 degrees or so, & in the 60 seconds I tried the cleat on, it made a huge difference. The three-wedge STL may be irrelevant to you, & I'd be surprised if you needed multiples of it.

Reference Image

Assembly & Materials

Print multiple & stack them depending on what your (qualified) fitter tells you.

Depending on how many you use, you may need longer bolts to avoid stripping threads at the female plate in the shoe.

People complained about the actual red BikeFit cleat wedges, saying that the necessary torque to adequately secure the wedges would crush the wedges, negating any angle they may have shimmed.

In practice, it definitely did look like the plastic yielded a lot. With enough of them (I got 3 on each cleat), the net angle was still there, though it will certainly not be purely additive.

I am concerned that the 3D printed material (HIPS, PLA, ABS, etc.) will crack under the considerable compression under the two bolts. Not tight enough, & you may lift your foot & find the cleat still stuck in the pedal, or just lose the cleat entirely somewhere on the road (you'll probably never find it).

I have not yet tested it, so if you beat me to it, please let me know how it goes.

I developed this because in previous experience, the rafters/brim I've seen seem like they could take the stress, because they weren't printed the same way as the actual target structure. Here's to hoping I was right.

Depending on your printer, you may not have the resolution to render a layer height of 0.40 mm, which could screw up the print & yield a single thickness. I'm not sure, but please correct me if this is actually a non-issue.

Updates

13 Jan 17: Not tested. Use at your own risk & report the results.

15 Jan 17: Printed a few off. I forgot to mess with the layer height settings (minimize them). I'm going to try them anyways. The 1 degree wedges had 2 layers, the 3-wedge assemblies came out with 4 layers. Checking with calipers, it was very close to the designed thin & thick thicknesses. Now we'll see if they crack under compression.

16 Jan 17: Mounted the 3-wedge ones last night, but the bolts were too short to reach. I tried two singles on each side, & the bolts barely reached. Highly recommend getting longer bolts. I just did about 10 miles, & they haven't cracked or anything. The cleats felt pretty secure, though 2 singles isn't enough for me.

3-wedge on the left, single on the right.

Thickness view of the single wedge.

Thickness view of the 3-wedge assembly.