Ken, I think this was, probably thankfully, a short-lived experiment by TA. The TA pedals I have bought more recently have been pretty much typical English/Italian thread. The more recent problem, a year or two ago, was that the pedal body finish deteriorated, with visible voids. This was reportedly caused by worn out dies and resulted in production, or at least supply to the US, being interrupted for a number of months. Not sure I've bought a pair since production resumed. It is reported quality is improved, but not as good as "In The Day". I might have an interest in buying or trading for the TA pedals you aren't using, as it is getting a bit difficult to find French thread TA's these days.
Not sure if your Stronglights are French or English. I installed the pedals in question back then on some French thread Nervar cranks on a Follis 172. The force required was a little more than I was completely comfortable with. Result was OK, but I probabaly in effect tapped out the cranks just a bit. I don't blame you for hesitating to use them on a really prized crank.
Regards,
Jerry Moos
Big Spring, Texas, USA
> From: Ken Wehrenberg <wnwires@htc.net>
\r?\n> Subject: [CR] TA pedal threads
\r?\n> To: classicrendezvous@bikelist.org
\r?\n> Date: Thursday, April 16, 2009, 9:49 PM
\r?\n> This thread topic is really a postlog to Jerry Moos's
\r?\n> postlog I will post below. His comments, in the archives,
\r?\n> are from 2003. Just this week, finishing up my 1977
\r?\n> Eisentraut "A" rebuild after wonderful refinish by
\r?\n> Ed Litton, I was attempting the installation of TA pedals
\r?\n> into Stronglight 93 drillium, inner ring removed and
\r?\n> polished cranks. I am not going to use the NOS TAs as I do
\r?\n> not think the threading is compatible enough to not damage
\r?\n> the crank and after all the work on the Stronglights, I am
\r?\n> going to just use Campy pedals instead, which fit like a
\r?\n> glove. Jerry's parting words about TA being too clever
\r?\n> by half-- I would say so.
\r?\n>
\r?\n> If anyone needs TA pedals or has a hint, please let me
\r?\n> know. Neither I of my mechanic friends recommend going
\r?\n> forward with the TA's short and round-top threads.
\r?\n>
\r?\n> Ken Wehrenberg, Hermann, MO USA site of Saturday and
\r?\n> Sunday's 3 stage Tour of Hermann
\r?\n>
\r?\n> Here is the original post from Jerry:
\r?\n>
\r?\n> [CR]TA pedal threads - a postlog
\r?\n>
\r?\n> I just did an experiment in response to some offlist
\r?\n> messages. I had
\r?\n> previously tried the TA pedals in a mid-priced mid-90's
\r?\n> Japanese crank.
\r?\n> Just now I tried them in an old Cyclotourist, probably
\r?\n> 70's vintage, and in
\r?\n> a Campy NR. In these cranks they initially show just a
\r?\n> hint of looseness,
\r?\n> though less than in the cheaper Japanese cranks. However,
\r?\n> the thread on
\r?\n> the pedals is shorter than the thread on the cranks. When
\r?\n> you begin to draw
\r?\n> the unthreaded "shoulder" of the pedal axle into
\r?\n> the crank, the pedal snugs
\r?\n> up a bit. It appears the pedal axle diameter is just
\r?\n> slightly greater than
\r?\n> the thread diameter. This makes the pedal almost as snug
\r?\n> in an English
\r?\n> crank as a legitimate English pedal would have been.
\r?\n>
\r?\n> Wow, are the TA engineers ever playing the cracks in the
\r?\n> system! They are
\r?\n> exploiting the slight differences between English and
\r?\n> French thread pitch,
\r?\n> what appear to be slight threading differences between
\r?\n> quality European
\r?\n> cranks and Japanese cranks, or at least less expensive
\r?\n> Japanese cranks, the
\r?\n> greater thickness of quality cranks at the pedal hole, and
\r?\n> the realtive
\r?\n> diameter of their pedal axle versus their pedal thread.
\r?\n> With all this, they
\r?\n> appear to have created a pedal that is ideal with new TA
\r?\n> Cyclotourist
\r?\n> cranks, a bit tight, but OK, with old French cranks, and
\r?\n> just a tiny bit
\r?\n> loose at first, but OK when fully tightened, on older
\r?\n> quality European
\r?\n> English threaded cranks, and maybe OK on some newer or
\r?\n> non-European cranks
\r?\n> as well.
\r?\n>
\r?\n> This is a real engineering "tour de force", as
\r?\n> the French would say. As an
\r?\n> engineer myself, I have to admire the cleverness of the
\r?\n> engineering,
\r?\n> although from a marketing point of view I have to wonder if
\r?\n> perhaps they are
\r?\n> being "too clever by half".
\r?\n>
\r?\n> Regards,
\r?\n>
\r?\n> Jerry Moos
\r?\n> Houston, TX