Finding Maximum Speed the Robot will Travel

How do you calculate the fastest the robot will travel given the mass of the robot and the specs of two CIM motors that we will be using on the drive train?

robot mass = 150 lbs (68.038856 kg)
CIM = 5310 Free RPM (85.5 rps)

The simple answer is if you calculate the speed at the wheel using your total gear ratio (gears and sprockets). And then find out the circumference of your wheel you will know distance per revolution (with no load)

Figuring out the loaded speed of your robot is a bit more complex because it will have takes into account losses in your transmissions, wheel slippage, etc.

There is a great spreadsheet on this site that does some of these calculations for you. It is located here

I do recommended that you ask a mentor or teacher to go over the math with you so that you actually understand what the spreadsheet is doing.