Hi all,

I'm riding a Campa Chorus Compact with a 12-25 cassette. The system itself would allow up to 29 teeth on a cog as a ridmaximum.

So there is this 13-29 cassette lying around in my shop that gets on the wheel when I ride in the mountains. As I'm doing a lot of long distance riding, brevets and stuff, I was thinking to mix the lower cogs of the 12-25 with the upper of the 13-29 to give me a good gear ratio on flats while making my life easy on the real steep climbs.

Will this result in excessive chain wear or does someone have it as permanent setup on the road bike?

Amox.

Good

That should work out just fine without any shifting or chain wear problems.

It'll work out great, but I've found that shifting is never quite as smooth as it was on the original. I think the fancy Shimano computers profile each cog according to the previous cog and the next cog for the absolute optimum shifting.

Of course, people rode for decades on plain tooth cogs. I haven't let this stop me at all.

I agree that it should work. There is one detail though that, while probably not fatal, may make shifting a little rough between certain cogs. From my experience, there appear to be two different version of Campy cogs. If you look at the gear numbers stamped on each cog, you'll see things like "29-A" or "13-C". Some Campy loose-cog cassettes come with all A-type cogs, and others are C-type, and the ramps don't quite line up. I found this out when I tried to convert a new 13-26 cassette into a 13-29 by reusing the 29 cog from a worn 13-29 and removing the 18T from the new cassette. So if you mix and match, *and* the two cassettes are of different types, you'll probably get rough shifts between the A-type and C-type gears (I never actually tried it in my case, so I can't say how good or bad it actually works).


I'm a big guy so I love the 13-29 on my compact double. Way more useful gear range for me than the 11-28 cassettes on Shimano/SRAM.

No problems as far as damage, but there might be a minor shifting problem in the transition between the two halves.

Cassette cogs are phased with the gates of cutouts positioned so the chain can smoothly move between the two adjacent cogs. One spline is wider than the others, so that the loose sprockets are installed correctly phased, and each gate's position is based on the size of the adjacent sprocket. At some point, the upper half of the cassette will be out of phase with the lower half making for a slightly sloppier shift across those two sprockets. Otherwise, everything else will be unaffected.

Ok many thanks !!

i just scuffled 2 8 spd cassettes with different cut outs to move from a 11-32 to a 13-32. i put a couple of cold miles on to test it out, shifted fine for me, more miles today.

I seriously doubt Shimano's computers are used to design Campagnolo cassettes.

+1....that gearing is my last line of defense against putting a triple on my Pinarello.

I mixed the 12-15 from a 12-25 with the 17-29 from a 13-29 and it did not shift well at all at the 15-17. Any time you mix cogs next to each other in a different order, the radial timing will not be right and the shifting will suffer.

I have mixed the 11-15 from and 11-25 11 speed with the 17-27 from an 12-27 11 speed and had better results, but it's still not perfect.