Tandem bicycle stem that is clamped around the captain's seatpost. The stoker handlebars are typically bullhorns or drop bars with "dummy levers" instead of brake levers for gripping. Because of the extra weight and stresses, tandem wheels may use a higher spoke count, sturdier rims, higher pressure tires, a stronger freewheel, dishless spoke configuration, or asymmetric wheels. Tandems wear out rear wheels faster than front wheels; therefore, they may use non-symmetrical wheel setups, such as more spokes or a sturdier rim on the rear wheel. The dish of a wheel measures the amount of asymmetry between the rim and the hub flanges.
Wire wheel by striking a wing of the nut with a special alloy mallet or "knockoff hammer". Some jurisdictions, including West Germany, prohibited eared hubcaps. Some manufacturers (e.g. Maserati) preferred to hold the wheel on the splined hub by capping with a single conventional unwinged nut requiring a special large spanner. In the 1960s even lighter cast alloy wheels became usual—at first with splined hubs and knock-off caps—and now predominate. New versions of wire wheels are still made but often with standard hub bolt patterns covered by a center cap to fit without adapters. At one time, motorcycles used wire wheels built