Wheel Spacer
A metal disc placed between the wheel hub and the wheel to increase the track width or provide clearance.
A wheel spacer is a flat metal disc, typically made of high-grade aluminum, that fits over the wheel studs and sits between the wheel hub assembly and the wheel. Its main purpose is to push the wheel outward, increasing the vehicle's track width or providing clearance for wider tires, larger brake calipers, or suspension components.
There are two main types of wheel spacers: slip-on spacers (which simply slide over existing studs) and bolt-on wheel adapters (which bolt onto the hub studs and have their own set of studs for the wheel). Using wheel spacers alters the vehicle's suspension geometry and increases leverage on the wheel bearings, which can lead to accelerated bearing wear.
Proper installation of wheel spacers is critical for safety. They must be hub-centric to prevent vibration, and the lug nuts must be torqued to specification with sufficient thread engagement. Poorly made or improperly installed spacers can cause wheel studs to shear off, leading to catastrophic wheel detachment.