The gearing of you mini moto is dictated by the number of the teeth on the front sprocket and on the back sprocket. The sprockets can be changed as an easy way to manipulate top end speed and acceleration, quite like changing gear on a mountain bike. A front sprocket with more teeth will improve acceleration, however the top end speed will be reduced. A larger rear sprocket will produce a higher top speed but acceleration will suffer. The gearing on your bike can be adjusted in accordance for the track you are intending to ride I.e. a small track with a lot of bends will suit gearing for improved acceleration, however a track with long straights will require a mini moto that is geared for a higher top speed.
