Campagnolo Rear Derailleur - Cage Size

I have a 10 speed Chorus rear derailleur currently set up with 13-29 cassette. According to this
configuration it must be a medium cage. However, the box that the rear derailleur comes in says it's
a short cage.

I want to get a 11-21 cassette (10 sp) and need to know if that would work with my rear derailleur.
Anyone know how to find out the cage size from the derailleur?

 

Dustin wrote:
> I have a 10 speed Chorus rear derailleur currently set up with 13-29 cassette. According to this
> configuration it must be a medium cage.

That assumes the short cage one can't work with a 13-29 just because it's outside Campag's spec (re
min & max sprockets). Derailleurs can sometimes be pushed beyond their official limits and work.

> However, the box that the rear derailleur comes in says it's a short cage.
>
> I want to get a 11-21 cassette (10 sp) and need to know if that would work with my rear
> derailleur. Anyone know how to find out the cage size from the derailleur?

First, find some pics on the web. Might be obvious. I know the short & medium ones look the same on
the Campag site (mistake, I think).

If still in doubt, measure distance between jockey wheels (from bolt centre to bolt centre) then
enquire again here and rec.bicycles.tech - to compare yours with those of other users.

--
~PB FA: 62cm Ti frame: http://tinyurl.com/6stt

 

Dustin wrote:
> I have a 10 speed Chorus rear derailleur currently set up with 13-29 cassette. According to this
> configuration it must be a medium cage. However, the box that the rear derailleur comes in says
> it's a short cage.
>
> I want to get a 11-21 cassette (10 sp) and need to know if that would work with my rear
> derailleur.

The only relevant difference is that, unusually, the 2002 medium's min sprocket is supposed to be 12
teeth (or 13 for the 2001) and the short's is 11. Otherwise, the mech having more capacity than
needed doesn't matter. Extra cage length handles extra excess chain. Short versions are used when
nothing more is ever required and to save weight (difference is 16 grams).

As there's only one or two teeth in it, I would try it and see how well it worked - even if I was
sure I had a medium.

--
~PB FA: 62cm Ti frame: http://tinyurl.com/6stt