Logitech G25 G27 G29 Standard Potentiometer Mod

thingiverse

This is my fix for worn out Logitech potentiometers. If your signal jumps around your pots are probably worn out. Sure you can clean them but it's a temporary fix. Apparently the original potentiometers were custom order so you cannot get them anymore. Simply substituting a standard off the shelf potentiometer won't work due to physical differences but even if you did adapt it, the rotation angle isn't very much the way the original gearing was done. A standard pot rotates 300 degrees and I believe the original gearing would only allow about 60 degrees of that. If my calculations are correct my design will provide about 240 degrees. Still not ideal, but with my initial testing they seem to give plenty of resolution. Limitations: I have not tested these connected to the original G25/G27 wheel as I use a separate Arduino Leonardo based interface. In theory, it should work but I cannot say if it'll give the full range. I believe Logitech's firmware/drivers do some sort of min/max auto calibrate but I never fully understood it. If you try please comment here. One hole needs to be drilled/filled in the frame to make this work since the gearing is different and therefore larger. I printed the large gear on FDM (Ender 3) and the smaller gear on my resin printer (Elegoo mars). I only have a few hours testing so I cannot guarantee longevity however I will modify the design if (when) it fails. To build: - Print the two gears and the template (frame mockup). - Take your pedal apart and replace the two gears with these. - I didn't re-use the small spring that went around the pot shaft. I think it exists only to prevent backlash in the gearing. Seems fine without it. Either way my design doesn't support it (yet). - Lay the template over the frame and drill or file out the hole. It's just a guide, your mileage may vary. You may want to oversize the hole so give the pot some play to get the gears to mesh perfectly though it seemed to work for me first try on two pedals. - Mount the pot in the hole and push the gear onto the pot. - When you reassemble, pay attention to the rotation of the pot to make sure when the pedal is fully depressed it isn't running out of travel and therefore would break the pot. - Once it's together test with a multimeter to make sure you are getting decently full range readings. Again it rotates about 240 out of 300 degrees so for a 10k potentiometer you should read about 8k worth of range. I've included the f360 file so please feel free to modify and re-post.