Okay, last one for a while I promise. This one is actually useful, unlike the 1.625" wheel one. This is a good setup to test some different things with a 775 drive, as it allows us to test anywhere from 4-8x 775s and see how the drive performs.
22.34lbs, with everything in picture. Only missing rivets.
12:60 32DP gear reduction off the motors.
16:70 20DP gear reduction to the wheel.
Theoretical free speed of 14.94fps; adjusted of 12.1fps.
The second gear reduction can also be switched to either of the following:
20:66; theoretical free 19.81fps; adjusted 16.05fps
14:72; theoretical free 12.71fps; adjusted 10.3fps
4"x1.5" VEX Colson wheels, 18T #25 sprockets with 12.768" spacing between wheels.
Tubing for testing will probably not actually be lightened, and a custom belly pan will probably not be manufactured (plywood or polycarb instead).
Custom parts include the gearbox plate for each side, 5 shafts cut to length per side (middle wheel shaft turned down on end to couple encoder), and side drive tubes. In this version I turned down the standoffs mounting the gearbox to be able to clamp around drive tube, but could just be a normal standoff to mount if desired.
Imgur Album
Questions/comments welcome. Let me know if you're interested in the CAD model, or would just like the print for the single gearbox plate.
You can't derail a thread that had no "rails" to begin with. - bkahl [more] 
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