Any wheel mechanically connected to the engine or traction motor that transmits propulsive force to the road surface. On a standard front-wheel-drive car, the two front wheels are the drive wheels; on a 4x4, all four wheels can act as drive wheels.
The dyno operator strapped the car down and positioned the drive wheels precisely over the rollers.
Related terms
Drivetrain
The complete group of components that generate power and deliver it to the road surface.
FWD
Front-wheel drive, a drivetrain layout where the engine powers only the front wheels.
RWD
A drivetrain layout where engine power is delivered exclusively to the rear axle.
4x4
A vehicle with four wheels where all four wheels receive power from the engine.
Wheelspin
The loss of traction that occurs when a drive wheel rotates faster than the vehicle travels over the ground.