[EricH]

Originally Posted by Cash4587

Smaller wheels = more torque

Not necessarily. There are other factors in play

Torque = Force * Distance, or T=F*D. If T= constant, then a smaller D gives a larger F, which would roughly translate into available pushing force (given your frictional coefficients being sufficiently high--maybe they are, or maybe it's 2009 and they aren't), so yes, you are correct in that sense.

On the other hand, remember that I said earlier that smaller wheels allow you to use less gear reduction to get to a given speed. If you were to take a 6" wheel and swap in 4" wheels, with no other changes, you'd see a reduction in speed and an increase in torque--but most teams with smaller wheels tend to run at least as fast as teams with slightly larger wheels, if not faster, which means that they've used that lower reduction to go faster, sacrificing some of that available torque for speed. This can actually lead to lower available torque if the reduction is taken beyond a certain point (determined by drivetrain design as a whole).

Just a case of a general statement being true most of the time, but be careful in implementing it to make sure that either it is true or that you've accounted for the possibility that it's false.