Shimano Mountain SPD Cleat Wedges

thingiverse

I recently volunteered as a test subject for a practice bike fit and discovered that the cleat wedges they installed provided significant benefits, but at a cost of $20, far exceeding their manufacturing costs. To address this issue, I designed and created my own cleat wedges using 3D printing technology. The design features a 1-degree incline with both thin (0.40 mm) and thick (1 mm) edges, ensuring a precise fit for the cleats. I made STL files available for both a single wedge and a three-wedge assembly. It's essential to note that these wedges are not recommended for installation without proper knowledge or guidance from a qualified bike fitter, as misuse can lead to joint or body injuries. Responsibility lies with the user in this case. Here's a detailed overview of how I designed these cleat wedges: I measured the dimensions of the BikeFit red SPD cleat wedges and used a green wedge image as a template for my design. The slot on the BikeFit red cleats constrained inside a rectangle of 8 mm width by 27 mm length, which served as a reference point. To create one side of the wedge, I employed lines and splines, then mirrored the result to complete the other side. An extrusion sketch was used to add thickness to the design, with a cut-extrude operation leaving behind a 0.40 mm thin edge followed by a 1-degree incline to the other side. The entire cleat sits on the edge of the wedge, which I believe is essential for proper function. To create the three-wedge assembly, I printed multiple 1-degree wedges and stacked them, ensuring an accurate angle despite potential imprecision from 3D printing technology. I also needed the three-wedge assembly personally, as maxing out my Bike-Fit Forefoot Measuring Device at around 20 degrees revealed a significant improvement in performance. The three-wedge STL may be irrelevant to you, but I'd be surprised if you needed multiples of it. Assembly and Materials: To assemble these cleat wedges, simply print multiple units and stack them according to your qualified fitter's instructions. Depending on how many wedges you use, you may require longer bolts to avoid stripping threads at the female plate in the shoe. Some users have complained that the actual red BikeFit cleat wedges are prone to plastic deformation under torque, negating any angle they provide. In practice, this issue is evident, but with multiple wedges (I used 3 on each cleat), the net angle remained intact, albeit not purely additive. Regarding material concerns, I'm worried that the 3D printed material (HIPS, PLA, ABS, etc.) may crack under the considerable compression from the two bolts. If you don't tighten the bolts sufficiently, your foot may lift off the pedal, or you may lose the cleat entirely on the road (you'll likely never find it). I haven't tested these wedges yet, so please let me know if you beat me to it and experience any issues. In my previous experiences with rafters/brim, I observed that they could withstand stress despite being printed differently from the target structure. Here's to hoping I was right this time. Depending on your printer, you may not have the resolution to render a layer height of 0.40 mm, which could compromise the print and yield a single thickness. If this is indeed a non-issue, please correct me. Updates: 13 Jan 17: Not tested yet. Use at your own risk and report the results. 15 Jan 17: Printed a few wedges off, but forgot to adjust layer height settings (minimize them). I'm going to try them anyway. The 1-degree wedges had 2 layers, while the 3-wedge assemblies came out with 4 layers. Checking with calipers revealed that it was very close to the designed thin and thick thicknesses. 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, and the bolts barely reached. Highly recommend getting longer bolts. After a 10-mile ride, they haven't cracked or anything, and the cleats felt pretty secure, although 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.