Hmmm
 

You know tank treads arent a bad Idea because you will have a O degree turning radius. but I really wouldnt only use 2 Cim's I would use 2 Cim's and 2 drills at the same speed. Err I dunno if that would work, but I was always a huge fan of 2 wheel rear drive with 2 Cim's with 2 Pneumatic shifted gears.

But I bet most rookie teams will try to go direct drive with the drills. I always use a multi speed tranny with any motor!

P.S. Anyone have a good design for a 3 speed thats Pneumaticly shifted, I can only manage a 2 speed in the given space. And Im also having a down shifting problem its a lil rough, but thats expected from helical gears right?

According to that paper, the freespeed is 5342rpm, but it's 4356rpm under normal load. 4200rpm is a conservative estimate.

No....do NOT use a 3:1 reduction and call it a day

We're using similar wheels and I'm reducing the CIMs by ~20:1

Yay, we finished mounting the motors to the 5/8" coupling gear shaft and found that we could easily hold the shaft in place and trip the fuse, so we def need more torque. 1:20 sound excesive, I'll look into a 1:8 ~ 1:12 range.

Thanks

Rather than guess, use this White Paper as a starting point.

Then, take the information you learn about speed and apply it to torque and see where you end up.

Math is better than guessing. (Only marginally.)

I think you have it reversed, according to dictionary.com here is the defenition of "gear ratio":

The ratio of the speed of rotation of the powered gear of a gear train to that of the final or driven gear.

Lord,
I have to go with everyone else on this. The gear ratio sounds too high especially with the 9
' wheels. The chalupa motors are strong but the gear ratio will allow you to go fast only if you can get the robot moving. That is a big "if" since the gear ratio will provide so little torque. 8-12 feet per second is a good guide.
As to the electrical draw, the 40 amp breakers are the dominant factor and I would predict some heavy action on their part with this design. Turning will be your greatest draw.

Like I've stated before, Our Team has (somehow) managed to get 15 feet per second with a 10:1 ratio using the 2 Chiphua Motors, and we still have loads of torque. We aren't a speed based robot...
Anyway, OUr drive is really nice and (if only) if chiefdelphi had a section dedicated to video clips, I'd show you our drive in action!
I might be able to get a file server and post a link in a while...
Anyway, we Haven't had any issues with it, and it works great!