# wobbling casette / bad hub / what to do?



## jacknapier (Nov 4, 2007)

For a few weeks now my chain has been making popping noises/trying to jump gears on the rear cassette but only when I'm putting a fair amount of pressure into it (ie climbing). I've had 2 LBS look at it; one said he straightened my hanger out and the other "adjusted" my rear derailleur but it is still happening during fairly intense climbs.

I had pointed out to both LBS that my rear hub has a wobble as I can easily see the cassette wobbling in and out slightly when i spin the rear tire. They both noted this but said not to worry about it as it is fairly common. ?? Looking at it now the wobble has gotten a little bigger and it starting to make my rear disc brake rub as the wheels spins. This must be what is causing my chain to try and hop as I think the chain and casette are in fairly good condition, and the popping/chain clicking only happens at one point during the pedal stroke and I'm guessing its where this wobble is at its worst point.

I am in need of suggestions, can a hub be rebuilt/fixed? How much might this cost? Is it better to just get a new hub instead of rebuilding? I've been wanting to go tubeless also but my back rim is taco'd a little bit so am thinking of a new rear rim....does a hub come with the purchase of a rear rim usually?

As you can see I'm not exactly knowledgeable about rims/hubs/bike maintenance in general. Current rim is a Mavic 317 and the hub is a shimano (dt i think?), bike is a specialized epic 06. 

Thanks for your help! :thumbsup:


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## gumbymark (May 25, 2007)

*Coupla things off the top of my head*



jacknapier said:


> Looking at it now the wobble has gotten a little bigger and it starting to make my rear disc brake rub as the wheels spins.
> 
> *There are two "working parts" of a rear hub. The "freehub" and the "hub" itself.
> 
> ...


Your problem may be nothing more than a worn chain and cassette or it could be that your hub needs a rebuilding.

Can you wobble the rear wheel at all by hand? If you can then it is likely a "hub" problem, if you can't then the "freehub" could be the cause.

First thing I would do would make sure the chain, cluster and drivetrain are all in good condition. Check the chain with a chain wear guage (some thing like this http://www.jensonusa.com/store/product/TL605A00-Park+Cc-3+Chain+Checker.aspx)


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## L4NE4 (Apr 24, 2007)

From building bikes for a little over a year now I might know what wobble you are talking about. What hub and cassette do you have? On lower end components the cassettes really do "wobble" as you say. The higher end stuff doesnt do this.

If I build a bike that retails for $350, the cassette or freewheel definitely has this wobble. However, if I put my bike on the stand and spin the wheel I can see no wobble.

As far as this causing skipping, not sure.


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## nachomc (Apr 26, 2006)

Tighten the hub? We noticed a wobble in my hub yesterday, pulled the wheel and tightened the hub. Problem solved.


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## jacknapier (Nov 4, 2007)

Thanks for the replies.

If i grab the rear wheel and try to wiggle it back and forth laterally there is some play, just a bit but it doesn't feel right, like there shouldn't be any. The skewer is also not totally straight, it is slightly crooked if you roll it on a flat surface. However the wobble is still there watching the tire even without the skewer in place. Also if I spin the pedals backwards and watch the cassette turn I don't see the wobble, its only when i spin the tire and cassette together that there is a definite wobble, plus you can hear it make very slight noise as it comes to that point over and over.

The rear cassette says Shiamano HG cs m760 and the hub is Shimano FH M525. The chain (sram pc 970 i think) and cassette are both in good shape, last LBS did the chain check and said it had plenty of wear left. 

The rear rim is not destroyed, I just don't think it'd be able to get a good seal with Stans because the lip of the rim is taco'd in about 1/8 of an inch at one point. Sounds like I could get the hub rebuilt but If I'm just going to go with a tubeless tire anyway should I just get it all new together?


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## ZoSoSwiM (Dec 2, 2005)

My brothers specialized Hardrock had a wobble from day 1. When you spin the wheel either direction it has a noticeable wobble when you're not pedaling. I've checked the hub and the lock ring but it doesn't help. It hasn't seemed to affect anything so I told him not to worry unless it gets worse.


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## MrMook (Apr 20, 2006)

For reference....this is generally what people mean when they say their wheel is "tacoed":








The rim will get dinged over time...especally if you're running your tires with the pressure too low.

Not sure where that wobble is coming from. Sounds like you may have bearing issues, but I can't imagine what. Any grinding noises?


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## nachomc (Apr 26, 2006)

jacknapier said:


> Thanks for the replies.
> 
> If i grab the rear wheel and try to wiggle it back and forth laterally there is some play, just a bit but it doesn't feel right, like there shouldn't be any. The skewer is also not totally straight, it is slightly crooked if you roll it on a flat surface. However the wobble is still there watching the tire even without the skewer in place. Also if I spin the pedals backwards and watch the cassette turn I don't see the wobble, its only when i spin the tire and cassette together that there is a definite wobble, plus you can hear it make very slight noise as it comes to that point over and over.
> 
> ...


This is exactly what my bike was doing..Assuming your LBS hasn't checked the hub itself, take the wheel off and finger tighten the hub by putting your fingers against the hub body behind the skewer, then turn opposite directions until that bad boy is tight.


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## Jwiffle (Jan 26, 2004)

If the wheel is in the frame, you should not feel play if you grab the wheel and pull back and forth. If there is, you need to adjust the hub bearings. Provided you haven't worn the bearings, cones, and hub too much from riding on loose bearings, it should be a simple fix. Loose bearings could cause your disc brake to rub. Hubs should be adjusted to have no play, yet turn freely.

A slight wobble in the cassette is not very unusual, though higher end cassettes usually will have very little wobble. I wouldn't expect much wobble from your cassette. If the hub bearings are loose, it could cause a wobble. But without being able to examine the bike first hand, it's impossible to tell if the loose bearings is the extent of your problem. But from your descriptions, it sounds like a loose hub, possibly with other issues as well, but I'm not sure.

As for going tubeless, if the wheel is in decent enough shape to use with tubes, it's in decent enough shape to convert to tubeless, even if there is a small ding in the rim.


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