Campagnolo 12 speed cassette compatibility

Discuss light weight issues concerning road bikes & parts.
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Joined: Fri Mar 24, 2006 1:26 pm

by DaveS

The Chorus RD should have a 39T wrap capacity, since it will wrap a 16T difference in front and a 23T difference in the rear. The higher level RDs might only have 37T of wrap. Chainstay length also affects the wrap capacity. The RDs must be designed to handle a worst case chainstay length, where 1 inch of chain must be added, just to get another 1/4 inch of wrap. They would never expect a user to have to put up with a chain hanging loose in the small/small combo.

Posts: 189
Joined: Thu May 04, 2017 7:30 am

by JoO

I am curious if anyone has tried campagnolo 12 mechanical ergos and RD with sram force 12 cassette and chain.
Would make an relatively affordable 1 X setup

by Weenie

Posts: 416
Joined: Thu Mar 21, 2013 3:19 am
Location: Southern Ontario Canada

by bikeboy1tr

DaveS wrote:
Tue Sep 03, 2019 4:00 pm
The OP came up with the same sprocket dimensions for Campy 12 that I did. Adding the sprocket thickness and space between gives you the center to center spacing of .137 inch or 3.48mm. Having the same two dimensions for the SRAM cassette would be valuable.

I've never read up on the exact difference in sprocket spacing between the brands with 11 speed, but I've read many reports that people think that all brands are close enough to be used interchangeably. I do know that Campy 11 spacing is a little larger. If the difference in the 12 speed cassettes is smaller, it would support the idea that the two are interchangeable. If the difference in spacing is only about .002 inch or .05mm, careful centering of the RD travel and adjustment of the limit screws should make it work.

As for Campy's 12 speed cassette design being hooey, I've never inspected a Record or SR cassette, but the Chorus 11-34 cassettes that I have are pretty slick. The last 3 sprockets are joined with no rivets or fasteners of any sort and they fit onto the same hubs that accept 9-11 speed cassettes. I can't complain about that. If you want to use a SRAM 12 cassette on a Campy wheel, all it takes is a Fulcrum XDR driver, that costs about 110 USD.

The SRAM chain is narrower, but it will work just fine with Campy cogs and chain rings, despite the .006 inch large diameter rollers on the SRAM chain. The SRAM chain follows the #40 drive chain design, while all other bike chains use the #41 drive chain specification, which are English standards for 1/2 inch pitch chains. You can convert anything to metric with multiplication by 25.4.

I've been using a SRAM Force chain on one of my Campy 12 bikes for several weeks with no problems. I've made several close visual inspections of the chainrings and sprockets and not seen any evidence of excessive wear and certainly no deformation of an aluminum chainring that one poster suggested. The little ring has the greater chain tension and I have a 32T little ring. It's the one to keep an eye on. I have two 48/32 crank and both were brand new a few weeks ago. I put the force chain on one crank from day one.
I am running the etap with a set of Campy Bora 35 wheels and Campy 11 cassette, also a Easton Aero wheelset Shimano 11 Ultegra cassette and I found that the etap and Sram Red chain run better with these combos than it did with the Easton Aero and a Red cassette. It was always slow shifting from 4th largest cog to the 3rd. Also I found the Sram Red chain was quieter and better shifting than the DA or CR.
I have in the past run 11 sp chains on my 10 sp shifters, and also 10sp chain on 9sp shifting. So my next thing is 12sp chain on my 11sp etap and preferably AXS.
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