This thread topic is really a postlog to Jerry Moos's postlog I will post below. His comments, in the archives, are from 2003. Just this week, finishing up my 1977 Eisentraut "A" rebuild after wonderful refinish by Ed Litton, I was attempting the installation of TA pedals into Stronglight 93 drillium, inner ring removed and polished cranks. I am not going to use the NOS TAs as I do not think the threading is compatible enough to not damage the crank and after all the work on the Stronglights, I am going to just use Campy pedals instead, which fit like a glove. Jerry's parting words about TA being too clever by half-- I would say so.
If anyone needs TA pedals or has a hint, please let me know. Neither I of my mechanic friends recommend going forward with the TA's short and round-top threads.
Ken Wehrenberg, Hermann, MO USA site of Saturday and Sunday's 3 stage Tour of Hermann
Here is the original post from Jerry:
[CR]TA pedal threads - a postlog
I just did an experiment in response to some offlist messages. I had previously tried the TA pedals in a mid-priced mid-90's Japanese crank. Just now I tried them in an old Cyclotourist, probably 70's vintage, and in a Campy NR. In these cranks they initially show just a hint of looseness, though less than in the cheaper Japanese cranks. However, the thread on the pedals is shorter than the thread on the cranks. When you begin to draw the unthreaded "shoulder" of the pedal axle into the crank, the pedal snugs up a bit. It appears the pedal axle diameter is just slightly greater than the thread diameter. This makes the pedal almost as snug in an English crank as a legitimate English pedal would have been.
Wow, are the TA engineers ever playing the cracks in the system! They are exploiting the slight differences between English and French thread pitch, what appear to be slight threading differences between quality European cranks and Japanese cranks, or at least less expensive Japanese cranks, the greater thickness of quality cranks at the pedal hole, and the realtive diameter of their pedal axle versus their pedal thread. With all this, they appear to have created a pedal that is ideal with new TA Cyclotourist cranks, a bit tight, but OK, with old French cranks, and just a tiny bit loose at first, but OK when fully tightened, on older quality European English threaded cranks, and maybe OK on some newer or non-European cranks as well.
This is a real engineering "tour de force", as the French would say. As an engineer myself, I have to admire the cleverness of the engineering, although from a marketing point of view I have to wonder if perhaps they are being "too clever by half".
Regards,
Jerry Moos
Houston, TX