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.
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.