BMW Genuine Motorcycle Tire Valve Stem Cap BMW BMW Genuine Motorcycle tire valve stem cap Motorcycle Tire Valve STem Caps are quality made from lightweight ABS plastic and finished in a durable chrome plated finish. The caps will fit any standard motorcycle air valve stem, and feature an "O Ring Seal", insuring consistent tire pressure and a clean valve oriffice when removed. The Head is knurled for ease of installation (clockwise) and removal (counter clockwise) without the need of a wrench.