pic: 2791 Drivetrain Close-Up

Here’s a close up view of 2791’s internal belt “west coast drive”. This drivetrain and custom single speed transmission made for a very simple and clean setup, hiding the drivetrain guts from our pit crew’s fingers and onlookers. Our drivetrain had its fair share of admirers at WPI and CT, something we certainly weren’t used to! Some teams just assumed the outer wheels were unpowered!

Its sooo clean!! But if you snap a belt or if you have to perform work on the intervals if the drive (belts ect.) how do you get in there?

looks sweet and clean. we do the same thing with gears (partially) inside the box tube connecting our inner 2 wheels, and chain inside the tubing connecting them to the outer 2.

Very nice!

Now, if you can only do something about all that neon green tubing…:slight_smile:

There appear to be sliders on each side of the central pulley. Is it safe to assume those are to ensure the proper belt wrap?

Very Clean, this style drive is something we will be looking into this offseason.

I am slightly confused I feel as if i must be missing something… how do you get enough traction between the belt and that pulley. It feels like there must be a detail not shown by this view.

Looks like the mounting plate is for another motor. Were you planning for 2 FP motors in the kit?

The part of the belt shown is probably the wrap going back from end to end. There is probably belt wrap under the part of the belt you can see.

IIRC, the drive was designed to accommodate 2 RS775’s, if 2791 saw the need for them.

I’m pretty sure it was.

Cleanest drive I’ve seen in a while.

Glad you’ve got your head on straight about axles now…


The access window you see, combined with the access at the ends of the tubes gave us enough room to thread a belt into the system and install it with about 7 minutes of work. We never had a belt failure, though.

Yes. I would highly recommend this style of drive to anyone, though using two belts instead of a serpentine belt is probably a little safer.

The picture is a bit misleading - it’s a top down view of a single serpentine belt, so you can’t really see how it engages the middle pulley. The bottom of the belt is wrapped around idlers to engage the pulley. The top of it (what you can see) just goes past it.

Always ensure proper belt wrap! It’s super important.

We added 2 more motors when we anticipated using RS-775s in our drivetrain. A 6 motor single speed seemed cheaper than a 4 motor shifter. Then we came in 20 pounds underweight and our motors had case shorts, so we didn’t really need them and pulled them off.

At least we understand squares. :slight_smile:

Do you know what the gear ratio is… it looks like it was originally a CIMple box and then you have a chain changing the gear ratio again… is this true

Thanks :rolleyes:

It’s designed to use the Toughbox gears. We probably should have used the CIMple Box gears, but we didn’t think to.

I believe the chain reduction is 10:24, so the final reduction is something like 8.5:1.