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Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

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Old 10-26-06, 01:42 PM   #1
charlisity
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Should I keep using this wheel?

I was riding on a relatively smooth dirt road when my front wheel got a bad wobble for no apparent reason. I stopped and the tire looked like it wanted to taco but didn't. I was in the middle of nowhere and didn't feel like walking my bike for miles so I removed my front wheel, grasped it by the two "raised" areas and pressed the hub against a tree. It sprung into shape with just a tiny wobble to show anything had happened. I rode it slowly for about ten miles of dirt road to my truck.

The shop couldn't find anything wrong besides the wobble that they removed by truing it. I am a total newbie and I'm wondering if this sort of thing happens to others and if they keep using their wheels after it does.

I posted this in the cyclocross forum and it was suggested that I post it here for more insight.
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Old 10-26-06, 01:52 PM   #2
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How bad was the wobble? Generally if it's < 1 cm or so, and can be fixed by truing, it means there's nothing wrong with the rim.

It sounds like you may have had "wound-up" spokes which unwound and loosened themselves... just a guess. Kind of mysterious really. If it's true now, keep checking it frequently for trueness (say every couple of rides) for a while and ensure that the problem doesn't return. If it stays true, doesn't crack, and is otherwise working fine after 10-20 more rides, you can probably forget about this incident.
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Old 10-26-06, 01:56 PM   #3
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^^ I was thinking that too but I would be a tad concerned if the shop "just" trued it, e.g. just laterally but not round, or without checking spoke tension evenness...which would expose deeper problems. But yeah, if they were able to true/round it with reasonably even spoke tension, it's probably fine, no worries.
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Old 10-26-06, 04:19 PM   #4
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One thing you could try would be to check every spoke with a tensiometer to see how close to equal they all are. alternatively you can try the musical plucking system to see if they all sound about the same.

Assuming you want to fix it yourself and don't have any special tools, try this:

1. Loosen every spoke until you have exactly 1 spoke thread showing. That'll take all of the tension off of the wheel but, assuming the spokes are all the same length, they'll be equal.
2. Now spin the wheel. If you're seeing a lot of side-to-side wobbling, more than 1 per revolution, that means that your rim is bent. If that's the case, your best bet is probably to replace the rim with a new straight one.
3. If the rim looks pretty straight, tighten each spoke 1/2 turn at a time and go around the wheel multiple times to slooowly bring the wheel back up to tension. Any time that you save by hurrying at this stage you'll pay back (with interest) during final trueing. When you think that the tension feels about right, go around the wheel squeezing parallel pairs of spokes together to set the elbows and nipples. Do a final trueing on the bike by tightening and loosening opposing pairs of spokes an equal amount and you'll be good-to-go.
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Old 10-26-06, 05:07 PM   #5
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Quote:
Originally Posted by charlisity
I was riding on a relatively smooth dirt road when my front wheel got a bad wobble for no apparent reason. I stopped and the tire looked like it wanted to taco but didn't.
This sounds a little like maybe the wheel might have been overtensioned. Jobst Brandt talks about how a wheel that is teetering on the brink of implosion due to overtensioning, will take on a potato-chip shape. The tension on this wheel should *definitely* be checked carefully, as mentioned above.
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Old 10-26-06, 05:35 PM   #6
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Sounds to me as if it was undertensioned (loose spokes), typical for new machine built wheels. On a local organized ride I came upon a young man with a new Trek, front wheel was so out-of-true that it would not turn inside the brake pads. I pulled out my Spokey wrench and did a rudimentary truing job and sent him on his way with a recommendation to take it back to the dealer for a complete tune-up, tensioning, and truing job.

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