In the 1930s reliable roller bearing coupling rods were developed. These machines were fitted with a roller bearing timing side main bearing. Before fitting the roller bearing, an axle collar is press fitted. These can be friction bearing, ball bearing, or roller bearing. The rollers typically rotate within a cage, as in a roller bearing. This was superseded by a standard high capacity roller bearing early in 1973. In 1898, Henry Timken was awarded a patent for the tapered roller bearing. He patented the tapered roller bearing in 1898. The machine was fitted with a roller bearing big end and a close ratio gearbox. Gear bearing is roller bearing combining to epicyclical gear. The roller bearing is pressed after the retraining ring. The spindle is mounted inside a cage containing rollers (looks like a roller bearing). A form using a cylindrical roller bearing with a resilient race was patented in 1930. By 1990 a roller bearing clutch was also introduced on all models. The rear axles in these two models are supported by a single roller bearing.