Bicycle wheel some other fixed point may be used as a reference mark, however this is less accurate. At one end of each spoke is a specialized nut, called a nipple, which is used to connect the spoke to the rim and adjust the tension in the spoke. The nipple is usually located at the rim end of the spoke but on some wheels is at the hub end to move its weight closer to the axis of the wheel, reducing the moment of inertia. Until recently there were only two types of nipples: brass and aluminum (often referred to as "alloy").
Wheel hub motor Wheel hub motor The wheel hub motor (also called wheel motor, wheel hub drive, hub motor or in-wheel motor) is an electric motor that is incorporated into the hub of a wheel and drives it directly. The electric wheel hub motor was raced by Ferdinand Porsche in 1897 in Vienna, Austria. Porsche's first engineering training was electrical, not internal combustion based. As a result, he developed his first cars as electric cars with electric wheel hub motors that ran on batteries. The Lohner Porsche, fitted with one wheel motor in each of the front wheels, appeared at the World Exhibition