At 3/6/2005 08:50 PM -0800, Gonzalez wrote:
>Has anyone in the group ever converted a right side crank to a left hand
>thread for a tandem timing crank? I have heard of using a Helicoil to
>do this but have never used one.
For years, tandem builder Terry Osell has just been running an LH thread tap through the RH threads. With the 1st set he did, he put a cheater bar on a pedal wrench and couldn't strip out the threads by overtightening. He's sold quite a few and hasn't had a failure yet. It should be pointed out that he's usually done this to create short cranks for smaller, presumably not terribly strong, riders. However the cranks he uses for this are cheap, melt forged kids cranks. Should be stronger if starting with a good forged crank. If you try this and do strip out the threads, you can always go with the Helicoil.
I've done the same to create 155mm stoker cranks for my daughter-in-law.
Terry has also built several recumbents with crossover drive, like a tandem. On a couple of his own machines, he simply installed stock Shimano pedals with Locktite and has one pair of shoes with the cleats installed backwards.
Mark Stonich;
Minneapolis Minnesota
http://mnhpva.org
http://bikesmithdesign.com