Will a short cage 10 speed pre-2009 Chorus rear derailleur work okay with 12-27 and 50/34?

Discuss light weight issues concerning road bikes & parts.
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OxfordGuy
Posts: 7
Joined: Fri Jul 20, 2018 7:32 am

by OxfordGuy

Will a short cage 10 speed pre-2009 Campagnolo Chorus rear derailleur work okay with a Centaur 12-27 cassette and compact 50/34 chain set without any drama? I try not to cross chain small-small or large-large, but don't want a disaster if that happens.

I think Campagnolo say a max cog size of 26T, but that was before the 12-27 cassette was available. Chain wrap would be 31 teeth, which I think is a bit over spec. If this is going to be marginal, I do have a Veloce Medium cage RD to fall back on.

by Weenie


NickJHP
Posts: 271
Joined: Wed Feb 14, 2018 2:22 am
Location: Canberra, Australia

by NickJHP

Back in the early noughties I used a short cage Chorus RD with the 10-speed 13-29 cassette and 48/34 chainrings, and that worked fine.

OxfordGuy
Posts: 7
Joined: Fri Jul 20, 2018 7:32 am

by OxfordGuy

Yes, but that's 4 teeth less chain wrap...

NickJHP
Posts: 271
Joined: Wed Feb 14, 2018 2:22 am
Location: Canberra, Australia

by NickJHP

No, it's one tooth less chain wrap...

(27 - 12 ) + (50 - 34) = 31

(29 - 13 ) + (48 - 34) = 30

bm0p700f
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Location: Glermsford, Suffolk U.K
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by bm0p700f

Yes it fine.

Catagory6
Posts: 399
Joined: Thu Feb 09, 2017 2:36 am

by Catagory6

i have the same setup with a 13-29 without any issue in any gear combo

OxfordGuy
Posts: 7
Joined: Fri Jul 20, 2018 7:32 am

by OxfordGuy

So no problems with the chain being too slack in small-small or too tight in large-large (not that you should really shift into that)?

dfischer1
Posts: 32
Joined: Fri Aug 01, 2014 8:19 pm

by dfischer1

I have that exact setup. It's fine.

RussellS
Posts: 873
Joined: Wed Feb 03, 2010 1:31 am

by RussellS

Back in 2007 PBP I used a Centaur short cage 10 speed rear derailleur. Chainrings of 46-30. Cassette was 12-28 I think. Everything shifted fine on PBP during many hours of night riding and pouring rain. And thousands and thousands of preparation miles before PBP.

Catagory6
Posts: 399
Joined: Thu Feb 09, 2017 2:36 am

by Catagory6

well, now i’ve found a hairline crack running verically in the back of the seat tube, right in the FD hanger area. its about 3 inches long.
i did the coin tap test, and it gives a clear, clicking noise. also tried to depress the crack, but it didnt move.
my next step will be to take it to the shop and have some one sit on the bike while its in a stationary trainer to see if anything happens in the crack

thing is, this is a de rosa protos v1. so its quite surprising that the FD would be deflecting when the bike is weighted.
and i didnt notice this phenomenon in the past.

OxfordGuy
Posts: 7
Joined: Fri Jul 20, 2018 7:32 am

by OxfordGuy

Catagory6 wrote:
Thu Apr 25, 2019 5:23 pm
well, now i’ve found a hairline crack running verically in the back of the seat tube, right in the FD hanger area. its about 3 inches long.
i did the coin tap test, and it gives a clear, clicking noise. also tried to depress the crack, but it didnt move.
my next step will be to take it to the shop and have some one sit on the bike while its in a stationary trainer to see if anything happens in the crack

thing is, this is a de rosa protos v1. so its quite surprising that the FD would be deflecting when the bike is weighted.
and i didnt notice this phenomenon in the past.
Is this posted in the correct thread?

andyfires
Posts: 1
Joined: Mon Sep 09, 2019 8:39 am

by andyfires

I'm using a 10 speed veloce which might be a 2005 or 2007 version with short cage derailleur, 53/39 chainring and 13/29 cassette right now. According to the manual, it shouldn't work, but I tried.
The result is, it works ok, but not as good as with a 12/25 cassette, I need to trim the front derailleur in some gears which I never need to with the 12/25 cassette, I'm not quite sure if that is caused by imporper installation. The pulley cage shakes when I use the 29 sprocket, but it works, when using other small sprockets, it is fine. The chain I use is record supper narrow chain with 108 links if I remember correctly which is the same length when I was using 12/25 cassette.

OxfordGuy
Posts: 7
Joined: Fri Jul 20, 2018 7:32 am

by OxfordGuy

BTW in the end I found a NOS medium cage Chorus 10-speed rear derailleur, which works perfectly with a 12-27 cassette and 50/34 chainrings

by Weenie


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