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Giant Boulder 09' Mountain Bike- Back Tire Wobbling

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Giant Boulder 09' Mountain Bike- Back Tire Wobbling

Old 05-24-14, 05:12 PM
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Biking4days
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Giant Boulder 09' Mountain Bike- Back Tire Wobbling

Hello everyone,

I seem to be having problems with my back tire as it is always wobbling and when I spin the tire it looks as if it is going to fall off. When I check the tire, it is on securely and I am having issues trying to figure out what it is that is wrong. The tire was constantly hitting the brakes making it very hard to ride. Right now I am riding without the use of the back brakes but I would like to know what is wrong with the tire and what can be done to fix it? I dented the rim a couple of years ago but got it repaired at the bike shop, and I think this could be the cause but I am not sure. Please see attached video for example of what I mean.Any input would be helpful.

Thanks

https://www.youtube.com/watch?v=r8ms852udrQ
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Old 05-24-14, 05:21 PM
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There's wobble, and there's wobble, so let's sort out what's happening.

If the wheel has play on the hub and you can jiggle the non turning rim, then you have play in the hub bearings. This is fixable, search "adjust bicycle hub bearings" for info, and tutorials.

OTOH- if the wheel is like a warped record and the rim moves side to side as it turns (but cannot be jiggled) than you need the wheel aligned, with involves spoke work, search "aligning bicycle wheels" for more.
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Old 05-25-14, 10:31 AM
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Thank you for the reply! I am going to take a look at the wheel now and figure out which one it could be. If I do need to get the wheels aligned, is it difficult to do for a first timer? May look into finding a bike shop to complete the work if the work is too difficult.
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Old 05-25-14, 10:55 AM
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fyi, Aligning is also referred to as "truing". It's not difficult with the correct sized spoke wrench, but depends on your aptitude for such things.

However, after looking at your video, the wobble looks like it's mostly in the tire, but some rim wobble also (2 separate problems), and that suggests the tire is not seated correctly all the way around.

Spin it slowly and look at the tire from the side where the tire meets the rim. If there is a mold line or something to use as reference, see if that moves up and down relative to the rim. I suspect there's a high spot. Lower the tire pressure so that it just barely holds it's shape, like 5 psi, and try to work the high spot down so that it is gone when you spin it. Then pump back up & ride.

If it's really seated poorly, and you pump up to the max, the tube can squeeze out and fail with a "BOOM".

Truing the rim should help also, although some problems cannot be fixed 100 %
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Old 05-25-14, 01:09 PM
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it is mostly or entirely caused by the tire

you said previously the brake was hitting the tire
but i do not know if you mean the actual rubber tire
or mis using the word tire to mean wheel
specifically the rim

misunderstanding the definition of the words
rim
wheel
and tire
is a very common mistake

if you are actually talking about the brake hitting the tire
then that is very likely the cause of the problem

if your brake hits your tire
which the tire is not designed to handle
it takes very little time for the brake pad to wear a cut through sidewall of the tire
which causes exactly the wobble you are experiencing

a clue that it is the tire and not the rim that is wobbling
is if you can feel the wobble while riding
because a rim has to be very bad to be obvious while riding
but a wobble caused by a cut tire is almost always obvious

the solution is to get a new tire before that one blows out
and it will
and figure out why the brake pad was hitting the tire
and rectify that
by adjusting the brakes
or fixing or replacing a warped or dented rim

Last edited by Wilfred Laurier; 05-25-14 at 01:29 PM.
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Old 05-25-14, 02:36 PM
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Hello guys thanks for the replies and yes it is the rim that is hitting the brake pads and causing the wobble. I marked the rim with marker at each spoke and figured out where the rim was hitting the wheel... I then did what others were saying and loosened the tight spokes, and tightened some of the loose ones around the wheel. I then noticed that one of the spokes was very loose...as I was tightening it, air started to come out of the rim and I realized that I had popped the air tube. The screw went through the elastic covering and I was not able to tighten the screw even after that. I don't know what to do to tighten it and also is it possible that I can just put some electrical tape on top of the screw afterwords or do I need to buy a new rubber band to cover all of them again. Check out the pics

Thanks
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Old 05-25-14, 03:31 PM
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you need to buy a rubber band (rim strip ) .
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