"We discovered this upon reading an enclosure in some Chorus platform pedals claiming that the pedals Would Not Work with Campy NR/SR/Victory/Triumph/C-rec cranks."
Michael, If the change took place in '83 why would it make anything incompatible with C, Tripophe and Victory which were all post-83 groups. While the thread diameter change that you mention may well have taken place, I doubt that this is the specific point that makes the newer Chorus platforms incompatible with the older arms. More likely it is the wider shoulder (introd with the Chorus and carried to Athena, and the triple bearing pedals, among others). The wide shoulders may not properly seat against the face of some of the older arms. More likely though the problem is the spindle poking out the backside of the arm (threaded portion is longer) and possibly catching on the chain (though way unlikely). Campy included, at least for a time, extra washers to go between the pedal and crank to keep the axles flush on the back side. I had this problem myself with Record triple bearing pedals on SR arms. Rather than install the washers, I used it as an excuse to buy a C crank.
Tom Dalton
> With all the fuss regarding pedal crank breakage,
> here is a wierd tidbit we
> just learned of that is sorta related to it. In
> 1983 or so Campy INCREASED
> the size of its pedal threads and also increased the
> diameter of the pedal
> hole in the crank. The argument was that it was done
> to make Campy similar
> to other cranks.
>
> We discovered this upon reading an enclosure in some
> Chorus platform pedals
> claiming that the pedals Would Not Work with Campy
> NR/SR/Victory/Triumph/C-rec cranks. We then spoke
> with an employee at a
> large Campy wholesaler who used to work for Campy
> USA who explained the
> story. In theory, use of a large spindle could
> cause stress on the arm and
> possibly lead to failure. Assuming that Campy stuck
> with this, then use of
> any later pedal such as a modern Campy clipless in
> one of these cranks
> should also be taboo! Are we oblivious, or has
> anyone else known, learned
> of, or cared about this? From experience and
> observation, this rule from
> Campy is/was violated continously.
>
> On another note, our experience from talking to
> folks is that Campy NR/SR
> cranks usually break near the pedal spindle and most
> often on the left
> side. They will break at the spider stress riser,
> but nearly every used
> Campy crank we've ever seen has a crack there - at
> least 85% of all used
> ones I'd say have some crack action.
>
> If I'm not mistaken, one should simply try to file
> ahead of the crack or
> keep an eye on it, and when it is really starting to
> show the arm should be
> discarded. Anyone who continues to ride a Campy
> crank with a really
> pronounced crack - and is aware of it - is simply
> providing more evidence
> that Darwin was right.
>
> Mike Kone
>
>
> _______________________________________________
> Classicrendezvous mailing list
> Classicrendezvous@bikelist.org
>
http://www.bikelist.org/
__________________________________________________
Do You Yahoo!?
Get email at your own domain with Yahoo! Mail.
http://personal.mail.yahoo.com/