Description:
Metal steel to increased wear resistance and improve fatigue life
Nitrided to enhanced hardness corrosion resistance
Tooth count: 21T 22T 23T 24T 25T
Tooth pitch: Mod 1 pitch
length: 14mm
For shaft: 5mm

Package include:
1 X Mod 1 pitch 21T pinion gear
1 X Mod 1 pitch 22T pinion gear
1 X Mod 1 pitch 23T pinion gear
1 X Mod 1 pitch 24T pinion gear
1 X Mod 1 pitch 25T pinion gear
5X Screws
1 X Hex Key

Make sure you thread lock the grub screw. They are hard to find when they fall out.
Larger gears will result in higher speeds while smaller gears provide more torque.
For quicker acceleration go for a smaller pinion gear (with fewer teeth) and larger spur gear (with more teeth).
Your car will accelerate off the mark very quickly with more torque, and you'll also benefit from cooler running temperatures, extending the life of your motor and ESC.

How to install the pinion gear:
You will probably need to loosen the motor a bit, in order to fit the pinion gear on. Make sure you lock it in place on the flat portion of the motor shaft.
When you are tightening it back up, make sure you leave about a gap between the pinion gear and the spur gear. That gap will be very small. It should be about the thickness of a piece of paper.