[DonRotolo]

In general, many of the larger motors in the Kit of Parts have too fast a shaft speed for them to be connected directly to the wheels. In fact, I would consider such a connection a safety hazard - those wheels will come apart at 3500 RPM.

So what is normally done is to connect the motor to a gear box or 'transmission', such as the AndyMark ToughBox provided in the kit of parts (look in the long chassis box). Then the output shaft of the ToughBox is connected to the wheel, either directly or through a sprocket and chain arrangement.

My advice is for you to look at images of robots in the CD Media section, to get some ideas on how teams have approached this problem. It would also be good if you could visit an experienced near-by team this week to have them explain your options.