Wheel clamps, once called auto immobilizers, come in a variety of configurations, but each works by preventing 360-degree rotational movement without seriously damaging the vehicle. This is achieved by enclosing one wheel in a Y-shaped brace consisting of a central faceplate, main arm and pair of swing arms.
The central faceplate’s function is twofold. First of all, it prevents access to the wheel nuts, which otherwise could be removed if left uncovered, allowing the wheel to be taken off entirely and replaced with a spare. Secondly, the plate also provides a protective barrier for the clamp’s locking mechanism, so this can’t easily be tampered with.
The main arm of the clamp, which can either be a separate component to the centre plate and swing arms or part of a single unit, acts both to prevent backward wheel rotation and also to enclose the wheel as tightly as possible. It achieves the latter by slotting through the faceplate’s locking mechanism before being secured by a bolt.
The swing arms complete the Y-shape lock and can dynamically rotate from the central plate. These arms sit at the bottom-front and top-front of the clamped wheel, hooking around the tyre to form a three-point brace. On certain models the swing arms can also be extended or retracted so the clamp fits a wider variety of wheels.