[henryBsick]

More traction does not slow a robot down. It increases the power required to turn. Watch the robot when it turns... it has to slide laterally. Wheels with a high coefficient of friction don't slide easily, therefor making it harder to turn. That is why there are teams that have pop-down sliders or casters. They allow the 2 wheels of the robot still in contact with the carpet to spin in opposite directions easily turning the caster or slider. Basicly..your wheels have to much grip for your motors to turn. The motors are geared too fast...the output through your reduction doesn't have the torque requiured to overcome the lateral friction on the wheels. If you want to turn faster...get a lower friction wheel, increase the numbr of motors on you drivetrain, or reduce the gearing for an overall slower robot, but able to turn. More information is needed though, for instance how many motors are on the drivetrain, the reduction, and the wheel setup ie:4 or 6.