Rear derailleur cage length?

[Gothard]

34-50 Campy compact crankset
13-26 10sp. Campy cassette

Which cage? medium or long?

[DarrenCT]

medium.

[Elefantino]

Medium.

Only run a long if you've got the 50-34 and the 13-29.

[Blue Jays]

You'll be absolutely fine with a medium-length cage with a 26-toother as the largest on your cassette.

[JGardner]

Medium

Here's what Campy says in their FAQs

Rear Derailleur (http://www.campagnolo.com/qea_search.php?gid=all&cid=1&pid=2&key=comp&rev=1)

[H.Frank Beshear]

I use a pre 06 Centaur short cage RD (the all silver one) on my bikes and it will shift 50-34/13-29 without any problem. I picked up the idea from Big Mac a few years ago. I see these new on E-Bay quite often, I've got a used one here that has a couple light scratches on it we could figure something out on as well. Let me know if you would be interested. Enjoy the day. Frank

[Pete Serotta]

George, with the 26 you can use a MED (campy advice) or a small (regular). I have used both. WIth 26 in back, just keep it out of the 50 in front for good measure (I am told).


I have used small and med cages and can not tell the difference in shifting crispness. I even know a fellow who used the 29 in back and a small cage with a 39/53 (only keeping it out of the 53-29) This was on the older Chorus/Record from around 2000-2001.


Regards PETE

[Dave]

It's all about RD wrap capacity and most people got this one wrong. A short cage RD can be used with a 50/34 and any cassette except a 13-29. See page 9 of the linked PDF.

http://www.campagnolo.com/pdf/7225195_Rear_derailleur.pdf

Before the days of the compact crank, Campy rated the wrap capacity of the short cage RD at 27 tooth, but now it's magically 29.

Of course a medium cage will also work, even with a 13-29. A long cage is never needed with a compact crank. It's only use is with a triple and a 13-29 cassette or a triple with a little ring smaller than a 30T. Even the medium cage will handle a triple with a 28T chainring. The chain may hang loose in the little ring and two smallest cogs, but those should never be used anyway. I've used this setup for the last four years.

[Gothard]

Thanks all. I will use a silver med cage Chorus with that setup.

If I got everything alright, I can in theory also use a short cage with a 13-29 and 53/39, PROVIDED I stay out of the 53/29?

[Pete Serotta]

:) Yes, you have it right (as long as you do not ride in 53-29).........

Regards PETE




Thanks all. I will use a silver med cage Chorus with that setup.

If I got everything alright, I can in theory also use a short cage with a 13-29 and 53/39, PROVIDED I stay out of the 53/29?

[Waldo]

[QUOTE=Dave]Before the days of the compact crank, Campy rated the wrap capacity of the short cage RD at 27 tooth, but now it's magically 29.
QUOTE]

Did the length of the short cage actually change or did Campy simply decide that the wrap capacity is 29 rather than 27?

And, please, somebody tell me it's OK to run 50-34 in front with 11-25 in the back with Record short cage. This combo has a 30 tooth capacity. Should I run 12-25 instead (29 teeth) or simply avoid the 50-25 combination?

[Dave]

[QUOTE=Dave]Before the days of the compact crank, Campy rated the wrap capacity of the short cage RD at 27 tooth, but now it's magically 29.
QUOTE]

Did the length of the short cage actually change or did Campy simply decide that the wrap capacity is 29 rather than 27?

And, please, somebody tell me it's OK to run 50-34 in front with 11-25 in the back?

The short cage might be OK with your setup, depends on your exact chainstay length. The perfect length can add up to 2T of wrap.

The RD cage length didn't change, just Campy's advertising. To insure maximum wrap capacity, the chain length should be set in the 34/12 combo (you'll never use the 34/11). The chain should be long enough to cause a small amount of RD cage movement and avoid chain rub on the upper pulley chain guide tab. If you want to see what the clearance would be like with a 1 inch shorter chain, shift up to the 16T cog. Double check the length by shifting into the 50/25, while on the work stand. As long as the shift executes, and the RD cage isn't overextended, you should be OK. In this special case, you could do the big-big test first, then the worst that will happen is the chain will hang loose in the little ring and several of the smallest cogs. 1 inch of chain equals 4T of wrap.