I came to fit a 10 speed campag cassette to a wheel today that had previously been running 9 speed and have found that the newer cassette lockring won't fit as its 27mm, apparently i need a 26mm diameter lockring to match the older hub. Any one have one or an old 9 speed cassette with one to sell?
Appreciate it is a long shot.
Hi, Gareth 01244, it's not clear from your OP, have you changed the cassette and the hub / wheel, or just the cassette?
If the hub previously took a 27 mm lockring (that's the thread diameter BTW), then regardless of the cassette, it'll still take a 27 mm lockring.
In some cases, if you get the orientation of the top sprocket wrong, so that it doesn't sit fully "flat" with regard to the next sprocket down, or if there is a bit of muck or some damage to the splines which means that the cassette ism't sitting all the way home or one sprocket is misplaced (and it doesn't take a lot), so the cassette as a whole sits slightly prouder of the cassette body than it should, the lockring threads may not reach the cassette body, so won't engage the thread - so it may be worth checking that - take the cassette off the body completely and try threading the lockring in - if it goes, lockring diameter is not your problem :-)
What you may have seen referred to online is that as Campagnolo transitioned from 8s steel cassette bodies, first to the Titanium cassette body, then to the aluminium with the earlly 9s hubs, they did change the lockring thread diameter. 9s hubs from 1997, 98 and 99 need a 26 mm lockring, if the hub is any more recent than that, the 27 mm will be needed.
You also need to be careful about what size the 1st sprocket it - on the 10 and 11s cassettes, an 11T top sprocket will need a different lockring to a 12T or 13T top sprocket as the chain touches the periphery of the lockring made for 12 and 13T if an 11T top is fitted.
If you do need the old 26mm lockring, they are discontinued now from the factory but Marchisio make a compatible unit that is still available - these guys are showing stock:
http://clemenzo.com/en/marchisio/lockrings/marchisio-lockrings-gmrcl
HTH
