I've been trying to do my own repair work for the last few months, so you can consider me a beginner bike mechanic. As a project to share with my son and learn a bit more, we are trying to get an old mountain bike in shape for him to take when he starts university this fall. It is a '91 or '92 Giant Yukon. I bought it thinking I would like mountain biking, but never got into it. The bike sat around our garage until about 5 or 6 years ago when I gave it to my son. It's taken a bit of a beating since then.

Anyway, we've replaced the saddle, grips, chain, and all the cables and housings and it is much, much better. However, it has a couple of problems with the freewheel and/or cassette for which I need advice.

The first symptom is that there is play in the cassette. I can rock the cassette back and forth about one half inch.

The second symptom is that there is a quick knocking (almost grinding noise) when coasting. This appears to be coming from within the rear hub; whatever is supposed to let the hub spin freely within the cassette is knocking or grinding.

I'd appreciate any advice you can give me. If it can be fixed and is not too complex and does not require prohibitively expensive specialty tools, I'd like to give it a go on my own.

Thanks for all the help so far.

Freewheel or cassette? I'm not sure either as the bike's age was right about the time cassettes became almost universal on better quality bikes but freewheels persisted for some time and are still used on the cheapest bikes. How many cogs does it have? Is there a lockring on the smallest cog?

Anyway, if you can rock the cogs a half inch, that says something MAJOR is broken. If it's a freewheel hub, I'd bet a lot that it's a broken axle. In any event, removing the axle and disassembling the hub is an absolute necessity at this point. Most of the tools needed are special bike tools but not very expensive:

Cassette lock ring tool or freewheel puller of the right type
Chain whip if you have a cassette
Cone wrenches and, most likely, a 17 mm box or openend wrench for the locknuts
10 mm hex key if it's a freehub.

Visit the Park Tools web site to read the tutorial on rear hub maintainance.

I guess I confused things using the terms freewheel and cassette. Sorry about that. Chalk it up to the learning process.

There are 7 cogs and there is a lockring. The lockring is stamped with "Shimano Hyperglide" and some numbers that I won't be able to read unless I find some magnification. If it will help for me to post those other numbers, I'll get my kids to help read them off. :-)

OK, then it's a cassette. The numbers are a US patent number and "tighten>40 N-m" which is the direction the ring tightens and the recommend tightening torque of 40 Newton-meters which is about 30 ft-pounds, i.e. quite a lot.

So. let's dispose of the obvious, is the lockring tight? If it has come loose, tighten it fully and see if that solves the problem.

Assuming it isn't that simple, you are in for a complete hub teardown to locate the problem Broken axles on freehubs are much rarer than on freewheel hubs but not impossible. At this point my best guess is a broken axle or a thoroughly destroyed bearing.

Ok. I'll go get the chainwhip and the lockring tool and report back when I've gotten a look inside the wheel.

I've partially disassembled the rear wheel. When I got the lockring off, I expected the cassette to slide off. Instead, the two smallest cogs came off, followed by the jagged washer/spacer shown at the far left in the photo of small parts below. The rest of the cassette doesn't seem to want to come off.

I can say this with confidence. The problem is neither a broken axle or destroyed bearing. Axle is out and is fine. Bearings are out on the drive side and are fine. Whatever is wrong is within what remains on the wheel.

So, questions...

Is this something other than a standard freehub/cassette? If the cassette is just stuck, what is the procedure to get it off without damaging something?

The following is a photo of the freehub and cassette remaining on the wheel...



The following photo shows the small parts that came off of the wheel. From right to left: 1) Lockring; 2) Gasket; 3) Smallest cog; 4) Next to smallest cog; 5) Spacer/washer sitting between cog 5 & 6.

The rest of the cogs will slide straight off the freehub body, may take some jiggling to get them loose initially. They will come off as a block. Try rocking the cogs to loosen them.
See if the freehub body ( the part the cogs slide onto ) has a lot of play. If so, the mounting bolt may be loose. This requires putting a hex key, usually 10mm, down the center of the hub and tightening the retaining bolt.
Other than that, the freehub bearings may be the problem, in which case it would probably be easier to replace the whole freehub body.

Mystery solved. When I removed the retaining bolt, the "innards" of the freehub fell out as shards and bearings. The freehub body itself took a lot of coaxing to let go of the cassette. When I did get it off, it was in two pieces. I'm not sure if it was in two pieces before my "coaxing" or not. Doesn't matter though because it was toast anyway.

So. Can someone recommend an inexpensive freehub that will fit my 7-speed cassette?

I would just put a WTB 7 speed MTB wheel on your local Craigs List. You should be able to find a good used wheel for less than the cost of replacing that hub. I bought good branded MTB wheelsets a couple of weeks ago off C/L for $10 a set ($5 per wheel), better wheels than what came on that Giant. That was a deal, but I bet you could get a good one for $25 or less (probably less) for the rear wheel.

Getting a used wheel is probably the most cost effective solution. But you can run a 7 speed cassette on an 8/9/10 speed freehub body if you get the appropriate spacer to go with it. Some tinkering may be required to get the seals to line up right.

You did two separate indenpendent operations:The additional operations you'll need to do is:


Check out this site: Park Tool - Freehub service

No bites on the CL WTB. I'm not surprised as Huntsville, AL is a pretty small market.

I bought a new freehub, but the retaining bolt won't go through the center. The portion of the bolt that is threaded seems to fit perfectly, but the non-threaded portion of the bolt is slightly larger. Does this say that I need to get a new retaining bolt (where?) or signify some other compatibility problem?

What kind of hub is it? If it's not shimano, I would not try to replace the freehub body, the compatibility issues can become a nightmare. At this point you might be better off getting a whole new wheel. The LBS may be reluctant (since they might want you to buy a more expensive wheel) but they should be able to order you a brand new double wall alloy wheel with 7sp cassette hub for under 50 bucks.

It is not a Shimano hub. It's hard to read, but I think it had "iL Cytech 931" stamped on it. Might be "991".

Well. I guess the saga ends here. LBS had a good price on a new wheel (no used wheels), but a GT MTB popped up on Craigslist that I could buy for $10 more. The tires on the old Giant were pretty bad so I figured I'd get two tires and a rear wheel out of it. Even though the old Giant is a better bike, the GT is flashier, in very good shape and my son prefers it. So, my son will be taking the GT to UA (Roll Tide!) and I'll still have an old Giant MTB with a bum rear wheel. I don't want to throw out the old girl so I'll probably keep looking for a cheap wheel. Maybe I'll outfit it to be a backup to my commuter.