_ I’ve worked on a few Positron shifting systems over the years. The Positron was Shimano’s first attempt at indexed shifting. But I have never heard of the Tokheim indexed shifting system. The Tohkeim Corporation, out of Fort Wayne, patented this system in 1972. That predates Positron by a several years. Thanks to Park Tool for unveiling this interesting piece of bicycle technology from yesteryear.
2/28/2012 06:01:55 am
I built a 2 speed once. I took an old Schwinn 20" Stingray and put on a dual front crank and a rear der. that functioned purely to wrap chain. Believe it or not; someone actually stole it!
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