A Brief History of Human Powered Transportation

Another transmission concept developed by Gentry in 1896 involved an intermediate spur gear between the crank and the rear sprocket. The 1898 Reading bicycle, shown on the right, employed this system which ran in an enclosed oil bath.

From: Adams, "Antique Bicycles," TAB Books (1981)

The gear ratio for this configuration could be changed by substituting gears with different numbers of teeth. The tooth size was kept small to reduce the friction between teeth, and the enclosure was essential to keep dirt out of the gears.