wrote:
upgrading from 8speed Chorus to 10 speed Record and trying to educate
myself to the different cage lengths for campy rear derailluers. I want
to run a 12-25 cassette and from what I read online about cage lengths,
the Campy short cage length would work fine, being able to throw the
chain to a 26t while the medium can throw the chain up to a 29t(if I
remember correctly). Other than this, any difference in performance
between a short and medium cage length? I don't expect to use anything
higher than a 26t as that my local bike shop recommended the 12-25 for
the terrain around where I live....I would think someone would use a
medium length cage so to use a more variety of cassettes...

Short (55mm) cage minimum 11t, maximum 26t, total capacity
27t with a max front range of 14t.

Medium(72mm) cage minimum 12t, maximum 29t, total capacity
36t with a max front range of 14t

Various Campagnolo publications move those numbers slightly
- sometimes the medium cage is rated for minimum 11t for
example- but you get the general idea. And those numbers
are conservative.

When you change cassettes, ensure your chain is the correct
length (span big-big and add 2 rivets) and try it on the
bike stand in all combinations before riding.

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