# A wheel wobble checklist?



## Opus51569 (Jul 21, 2009)

So, the commuter bike has developed a wobble at speed in the rear wheel. I have checked a few things, but what else should I be looking at before I throw in the towel and take it to the LBS?

Checked so far:

Tire - no obvious bulge. The tire seems to be seated evenly around the rim. It's a Schwalbe Marathon Pro 28c. I typically run it at 90psi. Could that be too low for commuting? The max pressure is listed as 100psi.

Spoke tension - feels even all around. I don't have a tension meter, though, to verify that.

Rim - has no obvious wobble or hop. 

QR - the skewer is good and tight.

Centering - the rim is centered in the dropouts. Looking from the back of the bike, sighting along the rim to the seat tube, though, the rim does seem to cant a little toward the NDS. A bent axle maybe?

Frame - is steel and hasn't been damaged in any way. The wobble has developed recently, so unless the frame has bent slowly over time, I'm not sure how that might be a factor.

What else am I missing?


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## FreeRojo (Apr 21, 2008)

You should check for excessive play in the wheel bearings.


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## Opus51569 (Jul 21, 2009)

FreeRojo said:


> You should check for excessive play in the wheel bearings.


Thanks, FreeRojo, I forgot to list that one, but I did check it and there's no play.


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## Mike T. (Feb 3, 2004)

Opus51569 said:


> a wobble at speed


Can you expand on this?


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## Opus51569 (Jul 21, 2009)

Mike T. said:


> Can you expand on this?


Sure. I don't notice the wobble when taking off or at low speed 5-10mph. Above that, I occasionally get a feeling as if the tire is "squishy" (technical jargon), almost as if its trying to slide off the rim. Above 15 mph or so, I get a fairly steady back and forth wobble from the rear wheel.


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## Mike T. (Feb 3, 2004)

Opus51569 said:


> Sure. I don't notice the wobble when taking off or at low speed 5-10mph. Above that, I occasionally get a feeling as if the tire is "squishy" (technical jargon), almost as if its trying to slide off the rim. Above 15 mph or so, I get a fairly steady back and forth wobble from the rear wheel.


The last time I knew of a wheel like that it was a rear wheel where a buddy had replaced a rim the night before we went mountain biking. Because he knew just enough about wheelbuilding to be dangerous, the didn't stress-relieve the wheel and ALL the spokes loosened after about 6 miles of riding. The wheel was unrideable - until I re-tensioned it trailside.

Are your spokes loose? Grab parallel pairs on both sides of the wheel and squeeze. Do they feel soft? Pluck the spokes with the finger, mid-span. Do they sound more like "plupp" than "ping"? The spokes' tones (on the same side of the wheel; don't compare sides) should be equal or very close.


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## Opus51569 (Jul 21, 2009)

Mike T. said:


> The last time I knew of a wheel like that it was a rear wheel where a buddy had replaced a rim the night before we went mountain biking. Because he knew just enough about wheelbuilding to be dangerous, the didn't stress-relieve the wheel and ALL the spokes loosened after about 6 miles of riding. The wheel was unrideable - until I re-tensioned it trailside.
> 
> Are your spokes loose? Grab parallel pairs on both sides of the wheel and squeeze. Do they feel soft? Pluck the spokes with the finger, mid-span. Do they sound more like "plupp" than "ping"? The spokes' tones (on the same side of the wheel; don't compare sides) should be equal or very close.


Nope. I've done the squeeze test with parallel spokes and they don't feel loose. I haven't tried plucking them, so I'll give that a shot tomorrow. Thanks for the suggestion.

Assuming they also sound okay, any other ideas?


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## Al1943 (Jun 23, 2003)

Does the rear axle fit in horizontal dropouts? Is it possible that the rear skewer (or axle nut) is loose on one side allowing the axle to slide a bit in the horizontal dropout?


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## Mike T. (Feb 3, 2004)

Opus51569 said:


> Assuming they also sound okay, any other ideas?


Not really.


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## Opus51569 (Jul 21, 2009)

Al1943 said:


> Does the rear axle fit in horizontal dropouts? Is it possible that the rear skewer (or axle nut) is loose on one side allowing the axle to slide a bit in the horizontal dropout?


I know the skewer is tight. I'll check, though, to make sure the axle is centered in the hub.


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## Kontact (Apr 1, 2011)

I'd look for a cracked frame at this point.

That is assuming that the problem isn't in the front wheel, headset, crank, etc.


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## Opus51569 (Jul 21, 2009)

Kontact said:


> I'd look for a cracked frame at this point.
> 
> That is assuming that the problem isn't in the front wheel, headset, crank, etc.


Yeah... I think it's going to come down to giving the bike a complete physical... Oh well, there are far worse ways to spend an afternoon I suppose.


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## bikerjulio (Jan 19, 2010)

Kontact said:


> I'd look for a cracked frame at this point.
> 
> That is assuming that the problem isn't in the front wheel, headset, crank, etc.


The only time I had a cracked downtube, I'd spent several rides checking the back wheel because it felt like it was wobbling.


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## wim (Feb 28, 2005)

Opus51569 said:


> Above 15 mph or so, I get a fairly steady back and forth wobble from the rear wheel.


I can't get my head my around a "back and forth" wobble. Does it feel like a forward-backward pulsation, i.e., a very slight acceleration followed by a very slight deceleration all the time above 15 mph? Or is it just something you see, but not feel?


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## Opus51569 (Jul 21, 2009)

wim said:


> I can't get my head my around a "back and forth" wobble. Does it feel like a forward-backward pulsation, i.e., a very slight acceleration followed by a very slight deceleration all the time above 15 mph? Or is it just something you see, but not feel?


Sorry, wim, "back and forth" was a poor choice of words on my part. It feels like a side-to-side wobble. I definitely feel it more than seeing it... which just made me think I should check my saddle and rails as well...


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## wim (Feb 28, 2005)

Opus51569 said:


> It feels like a side-to-side wobble. I definitely feel it more than seeing it... which just made me think I should check my saddle and rails as well...


Got it, thanks.

Because we get conditioned to things, sometimes having someone else ride the offending bike uncovers the problem right away. I remember a bike that I thought pulled "slightly to the left." When I let a friend ride it, he said "Holy crap, how can you even ride that thing?" He pointed out the problem, but I can't remember right now what exactly it was. Had something to do with the fork.

/w


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## Peter P. (Dec 30, 2006)

It's highly unusual to experience a wobble emanating from the rear wheel.

Swap out the wheel to verify it's the wheel causing the problem and not, as has been already suggested, a cracked frame.

Assuming it's the wheel, swap out the tire and tube to eliminate them as possbile causes.

After doing the above, if it still points to the rear wheel, repost.


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## Mr. Versatile (Nov 24, 2005)

Besides the fact you said the tire looked fine I'd change it & the tube, then try it.


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## Opus51569 (Jul 21, 2009)

*Update...*

So, I started with a little disassembly and inspection. No visible damage to the frame. 

I swapped out the tire with an older Michelin Krylion (25c) and reinstalled the wheel, rear rack and panniers.

Just got back from a 15 mile loop. No wobble, no squishy, no nothing. The bike rode just fine.

The rim is a Mavic CXP-22. The sticker on it shows you can run tires from 19-28. The tire was a Schwalbe Marathon Pro (28c). I know tire sizing can vary, so I'm wondering if the Schwalbe is just too large of a 28 for the Mavic rim. Either that, or there's a defect in the tire that isn't visible. Even stranger is the fact that I've put a few hundred miles on the tires without any problems. The wobble started once I started running the rack and panniers. I guess the extra weight made the difference.

Regardless, it looks like I spent $50 for a set of tires that I probably can't use. :thumbsup:


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## Kerry Irons (Feb 25, 2002)

*The clue!*



Opus51569 said:


> So, I started with a little disassembly and inspection. No visible damage to the frame.
> 
> I swapped out the tire with an older Michelin Krylion (25c) and reinstalled the wheel, rear rack and panniers.
> 
> ...


The tires will work fine and were NOT the source of your problem. There should be no problem fitting 28 mm tires on those rims.

The panniers and rack ARE the source of your problem. Perhaps the rack is not very stiff, or at least not stiff enough given the weight of the panniers and their contents. THAT is the source of your wobble.


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## Opus51569 (Jul 21, 2009)

Kerry Irons said:


> The tires will work fine and were NOT the source of your problem. There should be no problem fitting 28 mm tires on those rims.
> 
> The panniers and rack ARE the source of your problem. Perhaps the rack is not very stiff, or at least not stiff enough given the weight of the panniers and their contents. THAT is the source of your wobble.


I thought about that, which is why I reinstalled the rack (aluminum Jim Blackburn) and panniers before I took the test ride with the Michelins. I weighted the panniers as well.

Unless I accidentally corrected an imbalance of some kind when reinstalling everything, I don't think it's the rack and panniers that are the culprit.


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## Peter P. (Dec 30, 2006)

I have a bike with a rack and panniers. Rides like a dream, even with the panniers loaded. However, if I place even 5lbs. on top of the rack, it will shimmy, but only if I remove my hands from the bars. I don't feel anything is wrong with the bike; it's the high center of gravity created by the load which is the problem. Perhaps you're experiencing something similar.

I wouldn't toss the tires yet. Try a different tire and tube or swapping the front and rear tires. Even something as simple as a long valve stem may cause the wheel to oscillate at speed. Experiment by placing wheel magnets about the wheel to counterbalance whatever is causing the wobble. You might get lucky and only need one or two.


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## Opus51569 (Jul 21, 2009)

*Curiouser and curiouser..*

So, I get home from my commute yesterday with the Michelins. Still no wobble or squish. I look down and notice that the wheel doesn't looked centered. A closer inspection and, sure enough, the wheel is now noticeably over to the non-drive side of the dropouts.

Is this a re-dish issue? 

The bike seems to ride well despite not being perfectly centered.

Knowing myself, I know this is probably going to end up being one of those "fix it till it's broken" situations...


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## Mike T. (Feb 3, 2004)

Opus51569 said:


> the wheel doesn't looked centered........Is this a re-dish issue?


Only if the wheel is definitely solidly seated in its dropouts and the frame isn't broken.


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## Opus51569 (Jul 21, 2009)

Mike T. said:


> Only if the wheel is definitely solidly seated in its dropouts and the frame isn't broken.


Thanks, Mike T. There's no visible problem with the frame and the bike felt solid on the ride yesterday. I'll start with reinstalling the wheel to make sure it's seated and go from there.


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## Mike T. (Feb 3, 2004)

Opus51569 said:


> Thanks, Mike T. There's no visible problem with the frame and the bike felt solid on the ride yesterday. I'll start with reinstalling the wheel to make sure it's seated and go from there.


I should have said "Only if the wheel is definitely solidly seated in its dropouts and the frame isn't broken *or bent*."


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## Kerry Irons (Feb 25, 2002)

*Reinstall*



Opus51569 said:


> I thought about that, which is why I reinstalled the rack (aluminum Jim Blackburn) and panniers before I took the test ride with the Michelins. I weighted the panniers as well.
> 
> Unless I accidentally corrected an imbalance of some kind when reinstalling everything, I don't think it's the rack and panniers that are the culprit.


Any chance the rack could have been loose? Or perhaps the panniers weren't properly attached to the rack? If you reinstalled the rack and the problem went away it sure does not sound like the wheel was the problem. I have experienced significant rear end wobble with an off balance rack/pannier.


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## Opus51569 (Jul 21, 2009)

Kerry Irons said:


> Any chance the rack could have been loose? Or perhaps the panniers weren't properly attached to the rack? If you reinstalled the rack and the problem went away it sure does not sound like the wheel was the problem. I have experienced significant rear end wobble with an off balance rack/pannier.


It's possible, Kerry, and I do have to use p-clips on the upper seat stays. Maybe I reinstalled them more securely than they were before.


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