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,
Hubcap decorating one car with the wheel covers from another was common. Two very desirable wheel covers were those of the 1950 Cadillac (called the "Sombrero") and that of the 1953 to 1955 Oldsmobile, which resembled a huge, three-tined spinner. Aftermarket suppliers included the "Mooneyes" brand (named after the firm's founder Dean Moon) hubcaps and wheel covers that were some of the first independently offered for hot rods and custom cars. Another variant of the wheel cover, known also as "wheel shrouds" or "rim blanking", is that commonly associated with the German wheelmaking brand BBS since the 1970s. These are attached