UKC

I've got 9 speed Campag Xenon shifters and Veloce rear mech on my winter hack and 10 speed veloce on my summer bike and spare wheels. It would be handy to be able to have all 3 of my rear wheels compatible, so that in the event of finding an unexpected flat / slow puncture on my chosen steed before setting off, I can just swap a wheel over. Does anyone know whether the pull ratio on the rear mech is the same for 9 speed and 10 speed Veloce mechs?

In reply to Lord of Starkness:

10 speed and 9 speed chains differ in width, so the answer must be no.

But go and ask on Cycle Chat.

In reply to Lord of Starkness:
I'm not totally sure what you're asking. If you're asking if you can use a 9 speed mech on a ten speed block with ten speed shifter, the answer is yes I think.

I think the pull ratio is the same, in the sense that the mech moves the same distance for the amount of cable pulled by the lever, so mechs are not speed specific (except perhaps in minor details like the width of the cage which holds the jockey wheels). The exception to this is where a change in speeds coincides with a major shifter redesign, but as I recall this has only happened recently with brakes, not derailleurs.

So, in summary if you want to move to 10 speed you need a new chain, cassette and shifters. The rear mech should be okay and the front mech will probably be just about alright as well (technically it needs a marginally narrower cage). The chainset will also be fine as is.

In reply to Lord of Starkness:

Its not he mech that's the issue, its the snifters and chain that are, 9 = 9 and 10 = 10, what you expect to happen if you put a 10 speed wheel in a 9 speed system I don't quite know ?

In reply to Dark-Cloud:

Wheels / Freehub are 9/10 speed compatible so no issue there. Chainset is also 9/10 speed compatible as is front mech. Rear sprocket width is the same for Campag 9 and 10s - it's just that the spacers are different widths. I'm due a new chain anyway on the winter hack, so I'll get 10 speed shifters as well and the job will be a good 'un. If there's any problems, 10 speed Campag rear mechs are cheap as chips by comparison ( as long as you steer clear of Record and Chorus carbon body models)