Chorus 9 Speed RD/Cassette Compatibility

[NRRider]

What is the highest number of teeth I can use on a Chorus 9 speed RD without creating issues going big-big (I know that's a no-no, but sometimes I do it inadvertently and I don't want to mess up my spokes like I did once)?

[thwart]

Depends on the cage length, at least according to official Campy stuff. Many have used 29 tooth cogs with a short cage RD in both 9 and 10 spd set-ups. If you do so, though, it'd best to avoid big-big.

But, if you're like me, absent-minded and generally foolish on a bike, you may want to stick to 26... possibly a 28 (if you can find one), assuming you're talking a short cage RD. That would hopefully avoid calamity (and certain death) if you go big-big.

[oldpotatoe]

What is the highest number of teeth I can use on a Chorus 9 speed RD without creating issues going big-big (I know that's a no-no, but sometimes I do it inadvertently and I don't want to mess up my spokes like I did once)?

If the chain is the proper length, that is long enough to go big-big, NOT longer and certainly not shorter, you can use a short cage for 28t(9s) or 29t(10s).
I had a standard crank, 13-29, short cage on a demo bike for years w/o problem.

[Ralph]

I have a Campy Centaur 9 speed set up on a CAAD 5 Cannondale. 14-28 in rear and 39-52 in front. The C Dale has short chain stays and a short hanger, so if it will work on my bike, it should work on yours. All chain combinations work, not too much slack in little to little, and it will wrap the big to big. But it's about maxed out, and took a little working with B screw to make pulley clear the 28. Assuming your Chorus RD has same capacity as the Centaur 9 RD, a Campy 9's cassette with 28 will work....either the 13-28 or the 14-28 (both are available). No 29 tooth with 9's.

BTW....Edit addition. I seem to recall that some of the early short cage Record and Chorus 9's RD did not have the capacity of the Centaur 9 short cage RD.

[Dave]

What is the highest number of teeth I can use on a Chorus 9 speed RD without creating issues going big-big (I know that's a no-no, but sometimes I do it inadvertently and I don't want to mess up my spokes like I did once)?

I always have to throw in the reminder that some bikes can gain up to 3T of wrap capacity with the perfect chianstay length. The point being that what works on one bike, may not work on all.

The short cage length hasn't changed for a long time so the true wrap capacity should be the same for all. The current 11 speed short cage can wrap a 50/34 with a 12-29, but the B screw mechanism had to be changed to allow the upper pulley to swing further back.