Survey on new gear system

[Licramite]

Its present design has 5 set diameters of chain ring (counting the slots for the adjustable teeth sections) - if you looked at a system that expanded not vertically but radially you could have a chain ring with infinite diameters, which if linked to an activator based on the riders crank tork would give you a gear system that would provide the exact right size for every incline condition. - you would always be in the correct gear for your rpm
just a thought.

 

[Dogtrousers]

For Christmas I received a copy of the wonderful book The Dancing Chain by Frank J Berto. A must for anyone interested in bicycle history.

Anyway , here's a little extract:

"The first expanding chainwheel was the 1896 Linley & Biggs Protean. It expanded from 18 to 19 to 20 to 21 teeth [...] The 1903 Paradox expanding chainwheel expanded from 20 to 26 teeth in one tooth steps [...] The 1903 Mitchell any-speed rotated the chainwheel off-centre. The eccentricity changed the effective diameter. It provided infinitely variable gears within its range. After 70 years the expanding chainwheel reappeared. The Deal Drive had 16 speeds and a 2-to-1 range. It was well built and reliable. However it was heavy and expensive. It expired after two years. The 1983 Excel Cambiogear had 16 speeds and a 3-to-1 range. It was made of graphite fiber reinforced plastic. It lasted a year."

Also mentions The 1974 Hagan all speed expanding chainwheel