Bicycle wheel rims meant for use with disc brakes or hub brakes sometimes lack this surface. The Westwood pattern rim was one of the first rim designs, and rod-actuated brakes, which press against the inside surface of the rim were designed for this rim. These rims cannot be used with caliper rim brakes. The cross-section of a rim can have a wide range of geometry, each optimized for particular performance goals. Aerodynamics, mass and inertia, stiffness, durability, tubeless tire compatibility, brake compatibility, and cost are all considerations. If the part of the cross-section of the rim is hollow where the spokes attached,
Wheel hub assembly Wheel hub assembly A wheel hub assembly (WHA), also referred to as hub assembly, wheel hub unit, wheel hub bearing, etc., is an automotive part used in most cars, passenger vehicles, and light and heavy trucks. The WHA is located between the brake drums or discs and the drive axle. A wheel is bolted on it. Depending on the construction, the end of hub comes equipped with the splined teeth. They mate the teeth on the axle shaft. The axle hub spins along with the wheels bolted to it and provide the power to the wheels in order to rotate.