pic: 2012 frc971 transmission

[scottandme]

Originally Posted by AdamHeard

You get a little more freedom if you aren't set on running the belts internal. That would let you pick a lighter profile tubing for your frame as well.

That's true, I think it'll be the pulley diameter needed that dictates that decision more than the weight gain/loss. 2x1x0.125 is 0.8085 lb/ft vs 1.036 lb/ft for 2x2x0.125, so it's only ~1.3 lbs lighter all said and done. Probably figure some weight added when you push the gearbox further inside the chassis to accommodate the ~1.25" of belt.

It's been hard to find enough detail from some CD research, but here are some I found.

1625 ran 2x1 frame with 9mm wide belt http://www.chiefdelphi.com/forums/sh...ad.php?t=86668

2791 looks like they used 2x1 with a single 9mm belt in 2011, but I think they mentioned ratcheting going full fwd to reverse. Also needs idlers to maintain proper wrap, I would rather avoid that. (http://www.chiefdelphi.com/forums/sh...ad.php?t=94701)

2791's 2012 chassis looks like 4x2 tubing with two 15mm belts. (http://www.chiefdelphi.com/forums/sh....php?t=101454). More weight, and requires >4" wheels, but solves the belt problem at least.