No need for physics majors.
I've got to refer to this guy. Just type in gear ratios, it spits out torque, speed, and current draw numbers. It'll also indicate where cut offs for traction limiting is when you play around with the numbers.
http://www.chiefdelphi.com/media/papers/2059
You did your numbers with CIM normal load value, this means that the CIM can do this loading all day. Realistically for an FRC application, you should use
at minimum the max power numbers (171 oz-in, 2655 rpm, 67.9 amps). While there are other things constraining it (speed controllers, breakers, wiring, efficiencies, etc.), this will give you a better value. When I say FRC application, I mean short pushing matches, two minute matches, etc.
Let me just say, we used 4" x 2" roughtop wheels last year at a 10.75:1 ratio and they were still spinning up the wheels.
Do yourself a favor, use JVN's calculator.
I got to ask, how are you doing your center to center distances on gears?
Edit: Forgot to say, while I wrote about the max power numbers up there, the CIMs are capable of putting out 343.4 oz-in at stall current.