8X 775 SS WCD

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.

That is a pretty interesting setup! I love the low profile motor arrangement.

Did you calculate the torque at the wheels for eight 775 pros, that should be impressive?

Let us know how it goes.

Hm I like your gearing arrangement. Why 1.5" wide wheels over the 7/8" wide?
Overall, it looks like your main saving is in space inside the chassis, would have been very useful this year. What is your opinion on 775pro drives in general?

I’ve noticed that you lighten all the rectangular tubing on your drivetrains. Is that something you would do in a typical FRC game? How about for something like Stronghold?

As a repeated user of 6cim drive, I am very curious of the results that are possible from the proposed testing. I am most interested in the results from the 6 775pro 14:72; theoretical free 12.71fps; adjusted 10.3fps setup.

Please keep us updated if you do happen to do this in the “offseason”. Thanks.