Campy 12-30 Cassette Problems

[alexzorba]

I just made the change from a 10s 13-29 to 12-30 cassette. I have a 50-34 up front and a medium cage derailleur. According to what I've read this should work but the LBS just called to say that it isn't working and that the B tension screw is at its limit. They said its close, but not there. Any thoughts. I don't feel like I should need a long cage for this setup.

[Ralph]

It should work fine with 12-30 and 34-50....if chain is correct length. 34 tooth difference. Ideal for med cage.

[alexzorba]

The mechanic, pretty experienced, didn't seem to think the chain length was the issue. Chain was previously setup for 50-34, 13-29. Just said that he's maxing out the screw. Its a fairly old record mid-cage.

[Ralph]

Then let it "bump" when you occasionally go 34 to 30. No big deal.

[oldpotatoe]

I just made the change from a 10s 13-29 to 12-30 cassette. I have a 50-34 up front and a medium cage derailleur. According to what I've read this should work but the LBS just called to say that it isn't working and that the B tension screw is at its limit. They said its close, but not there. Any thoughts. I don't feel like I should need a long cage for this setup.

Chain is one link too long is my guess, w/o seeing it.

[Road Fan]

Chain is one link too long is my guess, w/o seeing it.

I agree, there are two more links to be wrapped.

[malcolm]

Chain is one link too long is my guess, w/o seeing it.

Would be my bet as well. Never used the 11spd stuff, but I've used a 13-29 with a short cage plenty of times, chain length becomes paramount. Medium cage should work fine with the proper chain length, but I'll defer to oldpotatoe.

[alexzorba]

Ok. Thanks Everyone. I'll give that a try and see how it goes. Makes sense.

[sokyroadie]

So do you actually hav a short cage RD? RE: your WTB med. Cage ad.

Jeff

[alexzorba]

The derailleur is medium cage. At first I thought that was the issue... I couldn't remember the cage length, but the LBS confirmed that the rear is in fact an older 10s record medium cage. At this point I may just grab a 13-29 cassette. I don't think they're going to resolve the issue at the shop.

[dan682]

FWIW, I installed this same setup on my wife's bike, but with the newest gen veloce short cage rear derailleur and it works fine with the B tension screw all the way out.

[Ralph]

The derailleur is medium cage. At first I thought that was the issue... I couldn't remember the cage length, but the LBS confirmed that the rear is in fact an older 10s record medium cage. At this point I may just grab a 13-29 cassette. I don't think they're going to resolve the issue at the shop.

All the med cage campy rear derailleurs are 74 MM cage length. So don't see how being old matters. Just ride it. So it slightly bumps when shifting to the 30 tooth, big deal. But....13-29's are $38 at Ribble. Or fix it...take out two links, put in a quick link. Your mechanic should fix this easily.....assuming it needs fixing.

[oldpotatoe]

All the med cage campy rear derailleurs are 74 MM cage length. So don't see how being old matters. Just ride it. So it slightly bumps when shifting to the 30 tooth, big deal. But....13-29's are $38 at Ribble. Or fix it...take out two links, put in a quick link. Your mechanic should fix this easily.....assuming it needs fixing.

I have a hard time believing the wrench could make it work with a 13-29 but not 12-30. Medium cage to boot. Go big-big, see how much slack in rear der..lots? Take a link out..not rocket surgery.

[gfk_velo]

It's just possible it's down to rear hanger dimensions - we have had a similar issue, similar symptoms, mounting the 11s RD to an older steel frame where the wheel centre to RD top pivot centre was less than 24 mm & trying to run a 29T bottom sprocket.

It may also be the location of the "hook" on the hanger - if that is set too far "forward" you'd get this result. This is part of the reason why the 2015 11s RDs have gown a "B Screw" where none had been on a Campag RD since model year 2000 ...

You can fix both these issues (or a good mechanic can) but the workarounds that help you to do it likely wouldn't be sanctioned by the frame makers & definitely not by Campag as they cover rectifying what, if this is the issue, is basically a "frame out of spec" problem :-(