In the kit there are gear setups color-coded with orange or green. The orange setups are for more torque or more punch off the line. The green setups are for more top end speed.
There will be three pieces that you'll use for each setup: a spacer (motor shim), a spur gear, and a pinion gear.
The parts are labeled as to the number of teeth on the pinion gear and the teeth on the spur gear.
The orange setup comes with 2 different spacers, 1 25-tooth spur gear, and 2 different pinion gears (8 tooth and 9 tooth).
The green setup comes with 4 different spacers, 1 23-tooth spur gear, and 4 different pinion gears (9, 10, 11, and 12 tooth).
For each gear setup you match up the pinion gear with the spacer labeled for that size of gear -- in other words, for the orange high torque setup you would use the spacer labeled 9-25 with the 9-tooth pinion gear and the 25-tooth spur gear.
Other parts in the kit are the 30,000 Stage 2 motor, metal motor heat sink (used in Step 10), and a pinion gear removal tool (Used in Step 8).
The different sizes of pinion gear will give you varying degrees of speed and torque. It's a matter of personal choice which size you choose. If one doesn't give enough speed or power, try the next higher number.
In this upgrade we're going for as much top end speed as we can muster so we chose the green 12-23 setup: the 12-tooth pinion gear and the 23-tooth spur gear along with the spacer labeled as 12-23.
