The Central Bore, also known as the C.B., is a vital mechanical component that plays a significant role in keeping a car’s wheels centered on the hub. In particular, for cars such as the BMW E93 335I, the C.B. is crucial. While it may not be as important as other components in a car, it still plays a significant role in ensuring the smooth operation of a car’s tires. The C.B. is located on the rear of a wheel and is a machined aperture that ensures the wheel is placed correctly on the vehicle’s hub. This hole is carefully cut to fit the hub, which ensures that the wheels are perfectly positioned when the lug gear is torqued down. When the wheel is placed with exact centering on the hub, the likelihood of vibration is reduced. Some wheels are manufactured with a bore that is matched to a single vehicle type since they are model-specific. For wheels that are designed to accommodate a variety of car models, a centring ring system is used to decrease the bore size to fit the hubs of those cars. This system ensures that the wheel is correctly centered on the hub, which helps to reduce vibration and improve the overall driving experience.