How to Properly Match the Pinion Gear on an RC Car

Remember that the combination of different spur and pinion gears will change the performance of the car. To set up your RC for fast acceleration, you need a higher gear ratio than you would need for crawling over rough terrain.
Some of the following combinations may help you:
Combining a small planetary gear with a larger spur gear will give your car maximum acceleration, but only for a short time.
Using a larger planetary gear than a spur gear will reduce acceleration, however, acceleration will increase when the motor gains power.
The larger the pitch on the pinion gear, the higher the speed of the car.
Types of Pinions
Rack pinions come in three different types,
1. Straight Teeth
The spur pinion has its teeth in a parallel position to the axis of rotation. It runs parallel to the gear axis, and the load movement is manual or back-travel.
2. Helical Teeth
This type of pinion provides uninterrupted meshing along the entire tooth length, and is quieter than the spur form.
In addition, due to the increased contact length, helical gears can carry heavy loads, but when on parallel axes, they have opposite directions, creating a thrust component on the rack and pinion.
This thrust adds more lateral loads to the structure. Helical gears are somewhat similar to spur gears in that they rotate in a plane, but their teeth are twisted in a helical path in the axial direction.
3. Roller pinion
This type of pinion drive uses rollers supported by bearings that are connected to the teeth of the rack to provide minimal clearance.
Click to learn: What are the types of motors?
4. Based on quality
Racks and pinions are also differentiated based on their quality.
5/6 tooth variants are very hard and have ground quality
7/8 precision variants have reinforced quality
9/10 milled teeth are milled and have hardened quality