about campy RD

[vav]

Hi forum;

I have been gathering bits for my first campy built. Just bought a 13-29 cassette. Don't have a RD yet. What kind do I need. Short, medium or long cage?
Thanks
Vincent

PS: Anyone with a silver RD 10 speed that wants to sale I am all ears btw.

[prometheus20]

You need a medium cage for this. It is exactly the set up I have.

[firerescuefin]

You need a medium cage for this. It is exactly the set up I have.

Any will work, including short cage. Been discussed quite a few times before.

[akelman]

You need a medium cage for this. It is exactly the set up I have.

As FRF says, you DON'T need a medium-cage rear derailleur to run a 13-29 cassette. A short-cage will do just fine.

[Dave]

As FRF says, you DON'T need a medium-cage rear derailleur to run a 13-29 cassette. A short-cage will do just fine.

Not always. Every bike is different. You can gain up to 3T of wrap capacity with the perfect chainstay length. That's why it works on some bikes and not on others.

[Ralph]

As Dave says.....you may or may not a need medium cage. I've used a short cage on a bike just fine with a 13-29. And on another bike, with short cage and 13-29 and 39-52, it keep throwing off the chain....no matter how I adjusted FD, B screw, and chain length. I had to keep the chain kinda slack to wrap up that much (39-52 and 13-29), that it couldn't take up the slack fast enough when doing a down shift in front....so threw off the chain. Med cage fixed that problem. I used to think all you had to worry about using a short cage with 13-29 was whether or not the upper pulley would clear the 29 cog....now realize it's more complicated than that.

Campy says use med cage for 13-29 probably because it is designed to work. Short cage doesn't always work. But agree....it usually does. BTW....med cage shifts fine....nice and crisp. So if buying.....I would get a med cage. If you already have a short cage....see if it works OK.

[vav]

Thanks guys. I don't have one yet.

[weiwentg]

so get the medium cage, just to be safe.

I had a short cage and decided to run a 13-29. it worked.

[akelman]

Has anyone actually had a short-cage Campy RD fail to work with a 13-29 cassette? I ask because I've used the combination on more than 10 bikes, ranging from cross bikes with longer chainstays to race bikes with shorter chainstays, and I've never come close to having a problem. Nor have I ever heard of anyone else having a problem with that combination in a real-world application. And that includes oldpotatoe, I'm pretty sure, who's probably worked on more Campy rear derailleurs than just about anyone around these parts.

[oliver1850]

Short answer, yes.

It was an 11 speed bike with a 34/50 compact; the 11 spd. small cog is a 12 instead of a 13, and combined with a compact crank, there was more chain length needed than the short cage could compensate for. There was no chain length that would allow it to work in all gear combinations. I think it would have worked with a standard crank (14 tooth ring differential vs. 16 for the 34/50), or with a 36 small ring on the compact.

[akelman]

That's what you get for going to 11 speed. (I'm kidding.)

[chismog]

Oliver has this right. It depends on more than just the cassette size, you have to take the chainring difference into account as well. Compact 34/50s will probably not work with a 13-29 and a short cage, that's a 32t wrap capacity required. Interested to see if anyone has gotten that setup to work properly.

I think we should be talking about max wrap capacity here and not cassette size?

[akelman]

I run nothing but compact cranks (34-50) with 13-29 cassettes and short-cage rear derailleurs. And as I said above, I've never come to close to having a problem. Still, if Mark has had trouble, that's that. It really does seem, then, like it's a safer bet, if one doesn't already have a short-cage RD lying around, to get a medium-cage instead.

[oldpotatoe]

Hi forum;

I have been gathering bits for my first campy built. Just bought a 13-29 cassette. Don't have a RD yet. What kind do I need. Short, medium or long cage?
Thanks
Vincent

PS: Anyone with a silver RD 10 speed that wants to sale I am all ears btw.

What you 'need' is a Campagnolo rear derailleur. A short cage will work fine, just make sure chain length is proper. Yes you can also use a medium cage or long cage and even a 11s one, w/o modification.

[oldpotatoe]

Has anyone actually had a short-cage Campy RD fail to work with a 13-29 cassette? I ask because I've used the combination on more than 10 bikes, ranging from cross bikes with longer chainstays to race bikes with shorter chainstays, and I've never come close to having a problem. Nor have I ever heard of anyone else having a problem with that combination in a real-world application. And that includes oldpotatoe, I'm pretty sure, who's probably worked on more Campy rear derailleurs than just about anyone around these parts.

Short answer-I've not seen a bike where it didn't work. For the poster who had 11s...?? Don't get it since most mid 2009 and all 2010+ rear ders are one cage length only...using a 10s short cage(pre 2009) with 11s....??

[oldpotatoe]

Oliver has this right. It depends on more than just the cassette size, you have to take the chainring difference into account as well. Compact 34/50s will probably not work with a 13-29 and a short cage, that's a 32t wrap capacity required. Interested to see if anyone has gotten that setup to work properly.

I think we should be talking about max wrap capacity here and not cassette size?

Ohh well...I had a Moots demo bike with a CT crank, short cage rear der and 13-29 for about 3 years and sorry, but it worked just fine.

I have installed many 13-29 onto CT setups and short cage rear ders and have not seen one that didn't work...chainwrap notwithstanding.

[chismog]

Fair enough! I'd certainly take you as the last word OP.

Do you use the chain length method of putting in small/small combo and removing enough links so it doesn't drag on the pulley? Then B screw adjustment after chain is installed?

[vav]

a short cage silver Centaur. Exactly what I was looking for :banana:

[Mark McM]

What you 'need' is a Campagnolo rear derailleur. A short cage will work fine, just make sure chain length is proper. Yes you can also use a medium cage or long cage and even a 11s one, w/o modification.

As far as I can tell, the only difference between the short, medium and long cage versions of Campagnolo derailleurs is the location of the idler (bottom) pulley. This will affect chain wrap, but not the maximum sprocket size.

I too have used a short cage derailleur with a 13-29 cassette. This worked fine with standard size double crank, but its chainwrap capacity was very seriously stressed with a semi-compact (52/36) crank. I'd recommend a medium cage when used with this combination.

[oldpotatoe]

Fair enough! I'd certainly take you as the last word OP.

Do you use the chain length method of putting in small/small combo and removing enough links so it doesn't drag on the pulley? Then B screw adjustment after chain is installed?

yep...not too long, certainly not too short. No droop in small/small and long enough for big-big.

[Dave]

One thing not mentioned is what users of the short cage consider an acceptable setup. It will always work if the chain is long enough, but the chain may hang loose in 1-3 of the smallest cogs.

The medium cage also has a slightly different "B" screw mechanism, to produce more clearance between the upper jockey pulley and the largest cog.

11 speed RDs didn't have the large capacity B screw mechanism when they first came out, as '09 product. That was changed for '10, so a 12-29 cassette could be used with a 50/34.