lothian

I took a spill on my bike that resulted in a shimmy in my back wheel. The wobble isn't excessive and I can still ride my bike. But it bothers me.

I watched a couple videos on how to straighten a warped rim, and I've searched this forum and others. The consensus for the repair seems to be: Remove excess warp then true the rim. Soooo... I removed the wheel and physically weighed into the rim to remove the worst; I then remounted it and tightened/loosened spoke nipples to pull the rim to center. This repair I've never had to do before, and to my surprise I got some good results. But just can't seem to dial it in. There's still some wiggle in the wheel.

A post in this forum suggests "riding out the wobble"--presumably the wheel will true itself due to the forces at play when under load? A bike shop I contacted says "true'ing a wheel is completely different than repairing a warped rim", and the latter should simply be replaced while the former should be performed on its replacement. This kinda makes sense to me, but I don't want to buy a new rim for this bike. I just want to fix my boo-boo.

Advice? Recommendations? ...for someone with the most basic specialty bike tools: funnel, hammer, circular saw, stand mixer, roomba, lineman's pliers, and (of course) duct tape.

pdlamb

I'd take a two step approach. FIrst, stress relieve the spokes. Grab pairs of spokes (wear leather gloves if your hands aren't well callused), and squeeze them together. Repeat all around the wheel on both sides. Then re-true again if necessary.

If that doesn't get the wheel true enough*, take the wheel to the bike shop and ask them to finish the job.

*True enough is relative. It shouldn't hit the brake pads at any point as the wheel rotates in the frame. Some people use dial calipers and aim for no more than 0.1 mm runout. If I can get mine within a millimeter or two, I'm happy -- I can't feel any wobble riding on my 32 mm tires.

Andrew R Stewart 

Most likely the rim, if not being pulled or prodded by the spoke tensions, has some wobble. So with the spoke tensions being used (truing the rim) to try to further reduce the wobble will be a challenge at best and in the long term the seed for more problems.

Whether to try whacking the rim straighter (with fully tensioned spokes or with loosened spokes) is a judgement and one that others will debate over. For me it depends on the amount of wobble, the rim's construction, the number of spokes and how many spokes the wobble involves. Obviously an equation with these many variables results in not a single solution, the same every time. This is where experience has it's value. But even with the thousands of wheels some of us have trued and the hundreds of wheels we have laced up a specific situation is still just a judgement and the results are not a given or even acceptable sometimes.

For the absolute mechanical acceptance a replacement is the only choice. For all else it's a try and see. It seems that you have discovered your wheel's and your ability's point of diminishing returns. This not to say "stop and replace" but to understand wheel work is not a digital process and awhile better described a s an analog process it's still only a make do. Andy

Russ Roth

Andy really covers it, my experience with warped rims is that they can only be brought back to acceptable and doing so should only be a short term solution. Rims just don't bend back to straight and once the damage is there the only solution is replacement. The big indicator is how the spokes feel, if there's noticeably less tension on one side to get the wheel straight then the rim is bent and a new rim should be installed. You can try removing all spoke tension, back off all the spoke nipples till you can see the same amount of threads on each spoke and the spokes are all easy to wiggle. Retension from there like building a new wheel, if you did a good job having them all have the same threads showing then you should be able to turn them equal amounts as you go around and if the wheel is noticeably out of shape once you get a moderate amount of tension on them then its time to move on.

branko_76 

here's a to the point video which should help you

Bill Kapaun

IF you didn't "kink" the rim, it probably went out of true due to a poor quality build.
WHAT was the nature of your "crash"?

I had exactly the same thing happen to the rear on my Globe when I did a panic stop/nose stand. The rear went way up in the air, I kind of stepped off to the side (basically holding a big hinge) and the wheel hit the pavement leaned over about 45.
It was bad enough to have to release the brake to ride home.
Wheel trued & tensioned up wonderfully.
It's NOT a beginner job. You're kind of thrown into the forest without knowing what a tree is.

ABQIan

The not-cost-effective, safe solution is to get a new wheel. You can screw then safely around with the old one and learn some things about trueing, or at least about what constitutes an irrepairable situation .

dabac

I’ve brought back some badly warped rims. But then I’ve unlaced them entirely prior to bending them back into flat. Those have been possible to lace back into round and evenly tensioned.
What determines if a thing like that is possible isn’t as much degree of bend, but rather stiffness. Some rims are so stiff that it gets very difficult to apply enough force to straighten them.

70sSanO

This speaks volumes. If you could ride it and the wobble wasn't excessive "before" you you started to work on it, then just stress relieve, ride it and check and tweak it to see if you can get it closer. That is if it is a lateral issue, if the wheel has a hop, then that an entirely different mind and skillset.

John

J.Higgins 

I like your style. When I was a kid, I apprenticed under some old guy that was a bike mech way back in the depression. Some of his methods were radical (and I'm not saying radical in any regional vernacular). Methods from an era when "disposable" was a foreign concept. I'm saying that some of his ways of doing things were so old-school - which were old school to me back in 1972 - have resonated with me to this day. As I've aged and have used some of his lessons now, I am fully astounded how well they work.

Andrew R Stewart 

[QUOTE=dabac;21431578]I’ve brought back some badly warped rims. But then I’ve unlaced them entirely prior to bending them back into flat. Those have been possible to lace back into round and evenly tensioned.
What determines if a thing like that is possible isn’t as much degree of bend, but rather stiffness. Some rims are so stiff that it gets very difficult to apply enough force to straighten them.[/QUOTE

I would suggest that it's harder to direct and contain the force needed to whack straighten rims then to generate enough force. Various methods can be done. Simple bending the wobble at the rim's most bent point is a common way. A block of wood on the ground, placed under the peak of the bend and two hands at the bend's ends then push down hard. This often results in the rim being bent back but too far but the peak is less. One issue is that a rim suffering a lateral bend will also have two opposing bends at either end of the peak. Like a "S" curve with a third curve, or 1.5 of a sine wave. How to also force these opposing bends complicates the corrective application of force. Another way is to hold the wheel horizontal to the work bench or ground and violently swing (the whacking motion) down onto the bench/ground with the peak centered. This method is surprisingly effective, if crude and frightening to others (and to the one doing it for the first time).

Here's a personal example. This happened about 8 miles out of Portland, ME at the end of a few hundred mile tour. I was following my late wife and she had stopped to take a photo (her schooling and hobby). My right front pannier trird to share space with her left rear pannier. Thus my ft wheel turned 90* and it folded over. I was only going about 10mph so the fall wasn't anything big, nothing hurt but pride and wheel. I could have let her go on and rent a car to pick me up or hitched a ride in but it was only 8 miles and early so why not try to fix it. Loosened all the spokes and whacked the high spot on the ground a few times till the wobble was only about an inch. Then retensioned the spokes and "trued" (in this case loosely used term) the rim AGAP. I was able to ride in to the motel but with the front canti disconnected, the tire cleared the fork and fender. Andy

Le Mechanic

Depending on how bad the wobble is will determine the long term durability of the wheel. If it has a lateral runout of a millimeter or two, just adjusting the spoke tension can correct the wobbly wheel. If it's out to the point where the tire is rubbing the frame, It's repairable but more difficult. I've made a few Youtube video tutorials on truing wheels from minor to tacoed, these are a couple of videos that might be helpful if you're wanting to attempt to repair the wheel yourself or at least know what's involved in the repair process. Also depending on the quality of the wheel and cost of a new replacement, as Andy said, replacing the wheel may be the best option for absolute mechanical acceptance.