i have miche hubs.. and the cog i have seems too thin for the lockring to hold it downn.. there are still cog threads exposed when fully tightened.. whats the fix for this.. are there cog spacers? or do i need a wider cog? help? thanks..

this has been discussed a lot here. i gather it's a common issue with certain cogs (pre-2005 Surly cogs, among others).

some people have used some kind of spacer on the inside of the cog, but most folks just get a new cog with the right width.

Your LBS should have some spacers. Mine gave me a 0.5mm spacer not too long ago.

Edit: it's just a thin washer, with an interior diameter just large enough to fit over the hub's threading. You put it on before you thread on the cog.

If you can't find spacers for it, a BB lockring (like from a kludge) would probably work just as well. It threads on the same direction as the cog. That might be too thick for the lockring to push against, but if you've got a lot of room, it could work.