lockring/cog advice

hi everyone
(asking this on behalf of a mate who bought some wheels off here last week)

basically,he bought a fixed/track wheel set with a double fixed rear hub, ambrosia I think.
We went to install a 16T miche sprocket the other day with a miche track lockring off wiggle.
The problem he's having is that despite the sprocket screwing on fine (clockwise as expected), the locking (which we've been doing anticlockwise) won't seem to grab enough thread for it to tighten. It doesn't seem to work on either side of the hub (which makes me think it isn't actually the hub at all).

Was just wondering if anyone knows what could be the problem? its a brand new miche sprocket with a brand new miche locking on a fixed wheelset. Could it be a compatibility problem between the different parts/brands? if not will take it down lbs and get them to have a look for him.

cheers for the help!, waterfall

miche lockrings are italian threaded

i'm assuming your friends hubs are not

im assuming you're probably right!
thanks, wheres best to get a cheap lockring from? might try px

This is a common and recurring problem. There are 2 common lockring sizes. I had exactly the same problem with Ambrosio hubs until I twigged what was going on.

http://sheldonbrown.com/gloss_l.html#lockring

Almost worth making this a sticky.

Which lockring did you go for mate?
Thanks

Brand? Not sure. When I pointed out the incompatibility to the wheelbuilder, he didn't actually know about this issue. He rummaged around in the shop and eventually came up with the correct ISO lockring.

Might have to try and english lockring then,thanks!

Any lockring except Mavic (French) Campag Phil Wood EAI Miche (Italian) will work.

Shimano best, Condor/Andel steel ones good, generic alloy meh