Chief Delphi - CIM Motor Differences

We are using Two Dual CIM motor and banebots transmissions (like last year) for our drivetrain this year, and are noticing some problems with the robot severly curving to the right (seemed more than normal). We replaced a bad bearing and fixed some overgrease in it, but are now thinking we might have a motor issue as well.

My question is, does anyone have any exact tested data on how fast the CIM motors by themselves in the forward vs. reverse directions?

I know there should be a difference, but in trying to isolate our problem we didnt know how much of a difference, and thought someone might have already run the tests and be able to save us a little time.

Thanks!!