Campy 8 speed, new rear mech.

rubberjungle

My Campy 8 speed bike needs a new rear mech.

Will a 10 speed one fit straight on as the indexing is controlled by the ergo levers?
Or is the ratio of cable pull to derailleur shift different.
Dont really want to have to convert the bike to 10 speed due cost.

Also what length cage would I need, I have a double 39/52 and something like a 27 large rear sprocket.

thanks all.

notsoracy rich

Have a look at this link http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3946 which gives the various cable pulls etc for different campag mechs.

I suspect you may be unlucky ,as it appears new campag mechs will not work with old 8sp levers.A new rear mech will have too much travel for the cassette spacing.

However you may be able to get a shift mate type device as mentioned in the article ,or custom spacers for your cassette which would also work.

Rich

rubberjungle

Thanks for the link Rich.

Sounds like you could be right although it does mention a 9 speed one should work but will overshift by 0.22mm per cog.

Does anybody have any experience of this setup?

Also on another forum somebody is using a shimano XT rear mech which he says works perfectly with campy 8 speed..Anyone know what the XT shift ratio is.
Campy 8 speed is
3.5mm of cable pull per click with 5mm cog spacing giving a ratio of 1.428 for the rear mech.

acorn_user

Your best bet would be to find a second hand or new old stock 8 speed or early 9-speed rear mech. They would work fine and it would be pretty inexpensive.

peanut

not tried it but SJS cycles claim a 9 speed will work fine with an 8 speed cassette.
The jockey wheels in the 9 and 10 speed rear derailiers are made with a huge tolerance in sideways movement of the jockey wheels to accommodate slight inaccuracies in setup or components unlike the old 8 speeds which had very little lateral play in the wheels. This should ensure that the chain will find the line it needs and run smoothly

Monty Dog

My experience is that a 9 speed works fine - there should still be plenty around on the likes of ebay