A Muzi <
[email protected]> wrote in message news:<
[email protected]>...
> Eagle Jackson wrote:
>
> > Will a Record medium cage derailleur work with a compact
> > (50-34) crank and 13-29 cassette? Or do I have to go to
> > a long cage?
>
> Yes and no.
>
> A couple of days ago I removed a 53/39 on a 13/28 bike
> with Campagnolo short changers, bolted on the customer's
> requested 30-40-50 triple ( same BB). It shifted
> acceptably for that customer but not acceptably, in our
> opinion, for a new bicycle.
>
> Since you own the medium changer, apparently, go ahead and
> change the crank. Then decide if the loss of the 34-15
> from chain sag bothers you enough to buy a derailleur.
>
> Derailleurs have ratings, which you will exceed, to allow
> use of all gear combinations. Specifically, one _should_
> change to a medium here, but since you apparently don't
> want to, you don't have to - you'll get full use of the
> low and high gears. Just not some of the near-crossover
> combinations.
>
> Since we are only the bearers of this news and find
> ourselves at the short end of some hostility over it, I'll
> close with this: There is some risk of the chain catching
> on the outside bottom edge of the rear changer's cage in
> the 34-13, wrecking the changer and the frame. Shortening
> the chain to avoid that trades 'possible failure' for
> 'impending doom'.
Thanks, this is very helpful.