Gerry Hull

Basic shimano wheel. Remove freehub for service. Clean, lube, repack bearings etc, mount wheel. Cassette wobbling like crazy and wheel dramatically out of true. Wtf? Did I forget to tighten freehub down? disassemble, do everything over. Wheel out of true in a different place, cassette wobbling. Dang. Something wrong with the washer underneath freehub? disassemble. Redo everything, with new washer, though it doesnt look any different from the old one. Check freehub part number, gotten direct from Shimano. Yep, it's the right one. Mounting surfaces perfect and surgically clean. reassemble and mount. Same thing. In desperation mark the freehub and begin mounting it in various positions on the hub shell splines. Find one position that seems ok, cassette not wobbling much, minimal retrue of wheel needed. Mount it and ride two blocks. Wheel all over the place now.

This tedious nightmare actually went on for quite a bit longer- i'll cut to th end. Two causes were identified: first, the aluminum washer sits in a washer-shaped shallow. Its not a close fit, though. And the inner diameter of the washer is exactly the same diametr as the freehub mounting surface. So unless the washer is perfectly concentric with the freehub, which its not likely to be, since it can slop around a bit in its groove, part of the freehub mounting surface is going to be squatting down on thin air. One side of the washer is crushed down more than the other, therefore cockeyed freehub, wobbling casette, homicidal frustration etc etc. Other factor, which was too difficult to
validate by measuring it, was that the splined part the sticks out of the hubshell was interfering with the recess in the freehub. In other words the washer (also factory matched shimano) was a couple thousands too thin. When I filed down the most protruberant edges of the splined thing, and employed voodoo arts to keep the washer fixed in a perfectly concentric position, problem disappeared. Wheel true, cassette wobble within spec. Just to make sure, I took it apart and remounted the freehub in a diferent position, everything still cool. I don't know which of the two causes was more responsible, but the problem wasn't fixed until I addressed both.

So far i've never had shimano stuff that doesn't assemble exactly like its supposed to,
so usually if something is f-ed up I assume I did it wrong. This is looking more like a manufacturer error, though. I'd rather think it was me. This is the closest I've come to being so defeated that I almost contacted the help desk.

I know the wobbling cassette thing is something that freaks people out, they drive their LBS mechanics nuts about it; they don't realize that, the way the freehub is designed, its going to wobble a tiny bit no matter how good it is, but this does not in any way
impede its function. After going through this business, though, I wonder if some of those complaints may be valid. I've only been working on bikes for about three years, though. Have any of you fellows with more experience seen things like this?

sorry for exhaustive length of post. trying to be succinct as I could.

The wheels are perfect now, and yet I sort of want to put them in a giant trash compactor and get a set of Mavics or something.
GH

Kimmo

Yeah wow, that's pretty surprising from Shimano. I've never seen anything like that...

LAriverRat

Use a shotgun or a sledge hammer or both. As my old pappy used to say, with a hammer and a blow torch you can fix anything.

rankin116

How does the freehub assembly affect the wheel being true?

cycle_maven

The wheel bearings are outboard of the freehub- if the freehub is cockeyed, then the axle won't be concentric with the hub and the rim will wobble.

To the OP- you've got more staying power than I have, and I thank you for it. Next time I have a Shimano freehub apart, I'll be looking out for this.

HillRider

Neither have I and I've had dozens of their freehbs apart for lube and overhauls and even freehub body swaps. They always go together with no problem.

MNRon

Well, the trueness of the wheel never changed, but the axle to hub alignment was not true so the plane of rotation wasn't in line with the frame. (Did I really say that?) Look, if it worked before you took it apart, then you shouldn't have to grind anything down to make it work after putting it back together. Something was done incorrectly, or placed improperly when being reinstalled. Just my $.02 worth...

Burton

Can`t say I`ve ever had an experience like that myself and have to give you top points for resisting the temptation to toss the upstart out into the driveway and run over it multiple times with the family sedan!

Hopslam

Does this hub happen to be a xt 2008- to current. If so I have wobble in cassette but no wheel true problem.The XT used to be sealed baring,now low quality made in Maylaysia ( insert slam here )

hillzofvalp

This thread was just started after mine. Seems like the same issue. My wheel is true but it wobbles a little bit, but more so with the cassette. Can someone help me get back on track? should I start by breaking the freehub down and checking for a washer?

Thanks.

Gerry Hull

Hey hillz,

Ive assembled a big bunch of wheels and not experienced anything like this before..this wheel was an rs-20 road wheel with the ubiquitous threaded steel axle, cones, jamnuts, freehub that mounts onto the hubshell with that big tubular bolt accessed from the outboard side. Most shimano wheels use some form of this system. There are exceptions, i think, maybe you other guys know which ones.

MNR- thanks for the term Plane of Rotation! That makes it so much easier to explain.

If a freehub mounts to a hubshell slightly cockeyed at the factory, its no big deal. The wheel is trued to the plane of rotation of the rim. That freehub might wobble a tiny bit more than its brothers, and its certainly more noticeable if you run a big cassette, but its not enough to degrade shifting. Some freehubs just wobble a bit more than others, because the freehub-hubshell interface is never going to be 100% perfect.

I've owned a couple of older sets of HED 3 wheels, which are trued by actually stacking .002" shims beneath the freehub, deliberately mounting the freehub cockeyed in order to get the rim within tolerance. Of course the freehub now wobbles a bit, but with your tiny 11-21 time trials cassette you dont really notice.

Were i trying like you, hillz, to simply reduce the degree of wobble (and im assuming the freehub itself is in excellent shape) I would first look at the aluminum washer between the freehub and the hubshell. Normally you can see where the freehub is crushed up against it, and that was one clue in my own case that something was not right. Even after torquing the freehub down to spec, it appeared that A) the washer was barely being touched- And B) it was easy enough for the washer to scoot around in its groove so that at some points the back of the freehub was barely sitting on it. (and yes, it was the correct washer, brand new, The one that came with the wheel, and I tried several replacements as well always getting the same result. The washer is fairly soft material, so if the freehub is not sitting on it right, it would be easy for one side of it to get crushed down more than the other.

The problem I had was very uncommon, I think, and more attributable to the washer being of inadequate thickness to give me proper clearance. Doubling up the washers would have solved it, but that would have screwed up chain alignment, so I opted to grind down the splined protrusion from the hubshell (what in the hell is that thing called?) just a bit. It resulted in a permanent fix. The freehub and the rim are now in the same plane of rotation no matter how I mount it, no matter what washer I use. In other words, like a normal wheel should be.

Anyway, hillz, check the washer. You should see a shiny, even, ring on it where the freehub sits. If not, or if the trueness of the wheel changes when you tighten the freehub down in different positions, I would advise a course of action slightly different from the one I chose: place wheel under tires of large motorized vehicle, and drive over it back and forth until its tin foil.
G

hillzofvalp

Ugh, well I guess I'll completely disassemble it and make sure everything goes back together snug.

And btw, the amount of the degree of wobble is very significant. So significant that it causes a noise from chain rub every revolution.

hillzofvalp

Turns out the spacer I had on there was a little deformed. Frankly, I don't know why I was using a spacer in the first place. Without it the big 23 cog is close to the hub flanges but not touching. allows for chain to fit so I don't see an isssue. However, with the cassette issue solved, the wheel is still wobbling a little bit, and I can see that it is at the hub.

Gerry Hull

Excellent work my man. You nailed it