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'.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971