Once upon a time, cars and trucks needed hubcaps to keep dirt and road crud from getting into the area where a wheel's hub encircles a vehicle's axle. Today, even the fanciest, most precisely machined rims still have a small hubcap, or grease cap, covering the stub end of an axle, but most of us probably don't think of these modest bumps as hubcaps. In the popular imagination, hubcaps were those flying-saucer-shaped platters that drew one's eyes to spinning wheels. Like hood ornaments, bumpers, and trim, these design flourishes, often plated in bright, reflective chrome or polished stainless steel, were rolling inducements to feast your eyes on the Pontiacs and Packards, the Cadillacs and Camaros, the discs adorned.
Most hubcaps feature a vehicle's logo, be it the Chevy bow tie, Ford oval, or Chrysler "pentastar." Some brands, though, stuck to plain old geometry, such as the so-called baby-moon or dog-dish hubcaps that covered the wheels of Cadillacs and Fords in the 1940s. Other wheel covers were secured to their hubs by three- or two-bladed spinner caps, which usually had the automobile's logo at the center—such hubcaps protruded from wheels, so were banned for safety reasons from new cars in the 1960s. By the 1970s, hubcaps were routinely made out of plastic, if they were used at all.