The American Haven Mercer has not only developed an automatic transmission for bicycles, he has also built a functional prototype and will receive a patent for it.

A spring-tensioned mechanism on the front crank ensures - when there is little pressure on the chain - that the circumference of the "chainring" increases and the gear becomes heavier or faster. At the rear sprocket, the mechanism is pretensioned in reverse and ensures heavy gears when there is little pressure on the chain and light gears when there is a lot of tension on the drivetrain.

The gearshift with the title Automatic Transmission System for a Bicycle thus offers automatic gear changes, previous gear jumps are a thing of the past. Compared to current shifting systems for mountain bikes, the current stage of development involves numerous mechanical components that could be affected by mud, snow or rockfall. 

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