Tire-rolling radius is the distance from the center of the wheel to the road. Static radium applies when the vehicle is standing still. Dynamic rolling-radius described wheels in motion. The latter is used to measure tire revolutions per mile and is usually slightly higher than static radius.

This is motion resisting force that is present from the instant the wheels begin to turn. On normal road surfaces, rolling resistance decreases with increased tire pressure and increases with vehicle weight. Rolling resistance can also be affected by tire construction and tread design.

In a vehicle with disc brakes, the rotor is the shiny metal disc that the brake pads squeeze to stop the vehicle. 1. The disc-shaped part of a disc brake assembly, upon which the brake pads bear; also called, brake disc. 2. The device mounted atop the distributor shaft, which passes current to the distributor cap tower contacts. see brake rotor

Revolutions per minute. RPM indicates how many times the engine crankshaft rotates per minute.

A laterally aligned structural member that is attached to the body or the frame via vibration-absorbing rubber isolators. By bolting suspension or driveline components to such crossmembers, automotive engineers can reduce the transmission of noise and/or ride harshness to the body.

An open sporting-type vehicle, lightweight, with two seats and with simple bodywork.

A long flat board under the car doors that acts as a footstep for the passengers.