Lubrication helps parts slide against each other and it is used to reduce friction in the bearings. Students should experiment with different lubricants to see which works best for their car. If the edges of a wheel rub on the body of the car, it creates a lot of drag. The axle holds the wheels and supports the car's frame. A larger axle takes more energy to turn than a smaller one.
Surface finish is critical, so make sure all of the running surfaces are as smooth as possible.
The transmission connects the motor shaft to the wheel or axle. In general, a transmission is any device which transmits mechanical power from one place to another. Transmissions are also used to change the speed and force proportions while transmitting mechanical power. Direct Drive - a motor shaft is attached directly to the drive wheel. Belt Drive - the drive wheel is directly attached to the motor using two pulleys.