ORIGINAL: Hack u 2
You are correct there is a big difference in tire size. Also the pinions are different between brushless and brushed they are sized different so order the correct one!
yeh, i saw from looking online that the brushed and brushless use different size pinion gears. that brushless motor has a 5mm shaft right?
since the XB has smaller tires, using the pinion gear that comes on it for the XTG will increase top speed.