Let's Make Robots!


2 Wheel Drift

I have a 2 wheeled robot - 2 GM10's with little thin wheels.  I've hooked them up to an arduino with an L293.  I have it going forwards, backwards & turning well enough.  The problem is when going forward, it seems to drift to the right slightly.  Any suggestions as to what the problem might be?  Do I need wider wheels?  A proper castor?  (ATM, the front of the chassis rests on the ground). 

Basically, what I'm asking is, with 2 small motors and thin wheels, can I expect a bot to go in a perfectly straight line?