MOBI > dpardo "Sickle" Cranks

The "dpardo" crank (, as of 2012/10) is a roughly 2010 re-creation of one of the most famous bad ideas in cycling, the 1980's P.M.P. "L" Crank.

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There are two major versions of the crank, the older model has a counter-clockwise "spiral". The newer model has a clockwise "spiral". There are also at least two arm profiles, two colors and two arm sections, one with a plain C-shaped section, and the other with a perforated C-shaped section.

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All variants successfully re-create the P.M.P. bad idea.

The "dpardo" Technology page (as of 2012/10, cached here) explains the crank's operation based on "Effective Force Area", which has no basis in physics or mechanical engineering, but also excuses the crank on the basis "The sickle crank's efficiency is fact and proved." It is unclear how the testing was done wrong, but the results are not physically possible. (The rider heart rate and oxygen consmption results are possible, because a rider can produce a given amount of work with varying efficiency. However the basic mechanical test can only produce the indicated results with some kind of experimental error.)