Wheel spacers are devices that are placed between the wheel and the hub of a vehicle. They help create additional space between the wheel and the body of the car. This can improve the vehicle's stability, handling, and appearance. Full definition
Five mm wheel spacers on the rear axle give the Panamera GTS a slightly wider track. (automobilemag.com)
The package also includes a set of H&R TRAK + wheel spacers made of high tensile aluminum. (topspeed.com)
If the wheels do not fit over the brake calipers, you could install a set of wheel spacers to move the rim further from the hub, allowing it to clear the brakes. (mechanics.stackexchange.com)