Bicycle Mechanics - Loose freehub. What's the problem????

My gear cluster has about 1/8" of side-to-side play when attached to my rear wheel. The whole cluster moves a little bit, not just one gear. For the life of me I can't figure out why it's loose. The cone tension is A-OK. The outermost gear that screws on is tight.

Do I need some sort of shim spacer or a missing spoke protector?

Dave

What kind of rear hub?

Shimano hubs have a hollow hex bolt that secures the freehub body to the hub shell. I'm thinking that if that bolt is loose it might cause the problem that you describe.

On many of my Shimano freehubs I use a spacer (or two) behind the biggest cog. The spacer is not one of the notched type like what comes with a cassette, but a thin alloy ring that is specifically to be used behind the biggest cog.

What kind of rear hub?

Shimano hubs have a hollow hex bolt that secures the freehub body to the hub shell. I'm thinking that if that bolt is loose it might cause the problem that you describe.

+1, but it could also just be play in the freehub itself.

Any hints on the age or mileage on the rear hub?

First check whether you need a spacer behind the cassette itself, or that the whole freehub is loose on the hub, like the others said. Bike shops will have the necessary spacer if that's the problem. If the freehub is loose on the hub shell, tighten it firmly to the shell with a 10mm hex key after removing the axle.

If the freehub's own internal bearing adjustment has loosened, you can remedy that by removing the axle, removing the dustcap on the freehub, inserting a Shimano TL-FH40 tool, and tightening down the bearing race firmly (it's reverse-thread, so lefty-tighty). It's not very common for this to happen, but I do see it once or twice a year.

Thanks very much gents!

Raleigh71