Another Campy Cassette Size Question.

There was a post in this group a few weeks ago about whether or not a 13-29 cassette could be used
with a short cage Campy derailleur. The general consensus was that it would work even though
Campagnolo says officially that it won't . I want to occasionally use that same set-up but here is
my question: I currently have a 12-25 cassette with a short cage derailleur which hits the largest
cog. I have adjusted the "B" screw to no avail and am wondering how a 13-29 would ever work if I
can't even get a 12-25 to work. Would shortening the chain help? It seems that by doing so would
increase the spring tension in the cage which would help to pull the derailleur away from the
cassette. I suppose I could just experiment with it but a little up front knowledge would be much
appreciated. Thanks Bruce

 

Just repeating what everyone else will say, your chain is almost certainly too long if the
derailleur pulley is hitting the 25 cog. Shorten it by one link and see if it hits the 25 cog.
Maybe you have two extra links in the chain. Of course if you shorten the chain for the 12-25
cassette, then it will be too short for the 13-29 cassette. So you might want to get the 13-29
cassette before shortening the chain. See if the chain at its current length is the right length
for the 13-29 cassette.

By coincidence I was counting my chain length last night. 54 full links (outer plates plus the inner
plate) for a 53-42 crank with a 13-28 cassette. Campagnolo. I would guess a 12-25 cassette with a 53
chainring crank would take 53 or maybe 52 full links. A 13-29 cassette would fit with 54 full links.

I was counting the chain links because I am assembling another bike with interchangeable components.

"Bruce" <[email protected]> wrote in message
news:<[email protected]>...
> There was a post in this group a few weeks ago about whether or not a 13-29 cassette could be used
> with a short cage Campy derailleur. The general consensus was that it would work even though
> Campagnolo says officially that it won't . I want to occasionally use that same set-up but here is
> my question: I currently have a 12-25 cassette with a short cage derailleur which hits the largest
> cog. I have adjusted the "B" screw to no avail and am wondering how a 13-29 would ever work if I
> can't even get a 12-25 to work. Would shortening the chain help? It seems that by doing so would
> increase the spring tension in the cage which would help to pull the derailleur away from the
> cassette. I suppose I could just experiment with it but a little up front knowledge would be much
> appreciated. Thanks Bruce

 

Bruce wrote:
> I currently have a 12-25 cassette with a short cage derailleur which hits the largest cog. I have
> adjusted the "B" screw to no avail and am wondering how a 13-29 would ever work if I can't even
> get a 12-25 to work. Would shortening the chain help?

Yes, if you can do so: It's a good idea to still have the chain long enough for the largest rear
sprocket + largest chainring.

> It seems that by doing so would increase the spring tension in the cage which would help to pull
> the derailleur away from the cassette.

That's right. It works well.

~PB

 

partly-<< I want to occasionally use that same set-up but here is my question: I currently have a
12-25 cassette with a short cage derailleur which hits the largest cog. >><BR><BR>

Shorten the chain one link.

And then put the 13-29 on and go ride..we do this all the time, regardless of what Campagnolo or
some web site 'experts' say.

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"