One-Way Bearing. This is a bearing that allows a shaft to turn in one direction only.

Pinion Gear. Electric RC vehicles use a pinion gear attached to the motor¡¦s shaft to turn the spur gear which in turn spins the rest of the drive train.

Piston. The piston fits into an internal cylindrical part of an engine called a sleeve and slides up and down during the combustion cycle the piston turns the engine¡¦s crankshaft via a connecting rod, converting the energy of combustion into rotational torque. The piston and sleeve of an engine are replaceable but must both be replaced at the same time.

Pitch. In its simplest terms, this refers to the size of a gear¡¦s teeth. For instance, a 32-pitch pinion gear has smaller teeth than a 48-pitch gear. The number represents how many teeth per inch .

Power Supply. A device that converts 110VDC to 12VDC.Generall used to power charging equipment.

Preload (shock). Adjusting preload on shock absorbers determines a vehicle¡¦s ride height .It is adjusted either by clip-on spacers or by tension clamps. Threaded shock bodies use a metal ring that is rotated up or down to adjust preload.

Prototype. A full-scale working model of an original new product or an updated version of an updated version of an existing product.

Receiver (Rx). The servo and ESC plug into this electronic unit in an RC vehicle. The receiver converts the radio signals from the transmitter into servos and/or electronic speed controls commands.

Resistor. The resistor is the ceramic unit on an electric vehicle¡¦s mechanical speed control(MSC)that limits the amount of current transferred from battery to motor. It dissipates the energy as heat.