Front sprocket for the GT125. Available in 13 or 15 teeth.

13 teeth = better acceleration

14 teeth = stock

15 Teeth = higher top end, less RPM and less fuel consumption at cruising speeds.

With a 13 tooth, At all road speeds, the engine will operate at higher rpm's where more power is available for better acceleration. Also, because of the torque multiplication effects of transmission gearing, the modified gear ratio has the effect of increasing the effective rear wheel torque by a computable amount:

Rear Wheel Torque with Smaller Front Sprocket = Rear Wheel Torque with Stock Sprocket x (14/13), a 7.7% increase.

The smaller sprocket lighter in weight and thus has less rotational mass to accelerate.

Another consideration is that installation of a smaller front sprocket will necessitate a small increase in the bike's wheelbase to maintain proper chain tension (in my case by about 5 mm). This will reduce the tendency of the bike to wheelie under acceleration although this is overwhelmed by the increased acceleration potential.

With a 15 tooth and our jet kit, acceleration will stay the same, but top end will be higher, and rpms during cruising will be reduced.