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Discussion Starter · #1 ·
I just have a quick question, i can true my own wheels pretty well, and i've even built a few 3x sets, but i'm clueless on how to take a vertical hop out of a wheel. Is it possible? I've searched MTBR discussions and google, but no real luck. I guess if you can take out wheel hop, how do you do it? I would think it would be pretty hard to do, but i really don't know, and don't want to poop up my wheel trying to find out. Thanks a lot!
 

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shiggy said:
Tighten or loosen the spokes in pairs to adjust the "roundness" of the wheel. Do an odd number and the lateral trueness is changed.
Do you mean pairs of spokes right next to each other on the rim? Which would be be spoke from one side of the hub and one spoke from the other side of the hub. Seems to makes sense, I'm just confirming for possible future need.

Mr. P
 

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Discussion Starter · #5 ·
I'm lost on taking out hops in the wheel from hitting something hard, the few wheels i've built didn't have flat spots in them, as they were brand new, and just needed the usual trueing.

Yeah, i hate to be a dork about this, but can you explain a little more with the pairs and everything? I would think if you tighten the spokes where the rim has a flat spot, it would pull the rim closer to the hub, and make the hop worse? Any more info will be greatly appreciated!
 

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A flat spot from hitting something means you have bent the rim. Whole different matter to repair - if it can be repaired.

I can not give you written instructions.
 

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You bottom feeders are all alike.

BottomFeeder said:
I just have a quick question, i can true my own wheels pretty well, and i've even built a few 3x sets, but i'm clueless on how to take a vertical hop out of a wheel. Is it possible? I've searched MTBR discussions and google, but no real luck. I guess if you can take out wheel hop, how do you do it? I would think it would be pretty hard to do, but i really don't know, and don't want to poop up my wheel trying to find out. Thanks a lot!
Something, on this morning with the rain and stuff, just made me say that. :D

Rick
 

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Work hardening

shiggy said:
A flat spot from hitting something means you have bent the rim. Whole different matter to repair - if it can be repaired.

I can not give you written instructions.
I am not an expert on wheel straightening but know something about shaping metal. When the wheel was first formed it was shaped which "sets" the metal. If you tried to straighten a round wheel, the metal would split a lot without a lot of energy input in the form of heating it up until it is plastic to reshape. In your case what you want to do is to take out a flat part, essentially returning the metal to round. The fact that the area flattened is the same as working the metal. The more the metal is worked without heat, the more work-hardened the metal gets. You see this in body work on an auto all the time. They can only repair a fender by beating it back into place "so much" before they either have to replace the fender (or part of a quarter panel or etc.) as the metal will not "work" - go back into shape without tearing. You should have seen what I had to do to an Internation scout years ago. The fenders were AFU, and that is all I had to work with. After a lot of pulling and many metal tears, on went the bondo. That was the only Battleshop Grey Scout in the area. But, I digress.

For the rim, putting it back into round is a matter of degrees. If there is little deformation and a fairly thick STEEL rim, the rim could be worked back into round, but it will undergo some work hardening. If it is an aluminum rim, then you have a different problem as aluminim does not work like steel. It is likely to fracture (tear) by working it back into shape, unless, again, the deformation is small. I have an aluminum road wheel some 20 years old with just such a deformation. It still is fairly round, but not totally round. Still works but I don't use the bike much anymore.

But, after the wheel is back into round be it steel or aluminum, the area that was flattened and reshaped is work hardened. It is much more brittle than the areas around it. It will fail easier than the rest of the wheel. Again, it is relative to the amount of deformation that took place.

How would you shape it? you need a form or mandrel to work it against to return it to shape. If the wheel is a urban beater that just has a small deformation, I would just true it up as best as possible and use it as is. If there is a large flat, I would toss the wheel. If the wheel is round but the flat is just on the sides that the wheel clinches to, get out the pliers and straighten it some. Too much and you can have a break from work hardening.

If the wheel is not a single-walled one, I would toss it. It is my opinion that you cannot reshape a complex cross-section wheel with any hope of it being reliable.

Of couse, I could be full of sh$t also, please consider that. Take it to a local wheel guy with some experience and get his opinion.

Hope this helps.

Rick
 

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badlander said:
I....... Take it to a local wheel guy with some experience and get his opinion.

Hope this helps.

Rick
This might be the best thing to do.

But once a rim is bent getting the wheel straight and true is the easy part, the hard part is keeping it straight and true. Truing a bent rim results in such uneven spoke tensions that the wheel will go out of round seemingly instantly and will require a lot of attention for the remainder of its life.
 

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badlander said:
I am not an expert on wheel straightening but know something about shaping metal. When the wheel was first formed it was shaped which "sets" the metal. If you tried to straighten a round wheel, the metal would split a lot without a lot of energy input in the form of heating it up until it is plastic to reshape. In your case what you want to do is to take out a flat part, essentially returning the metal to round. The fact that the area flattened is the same as working the metal. The more the metal is worked without heat, the more work-hardened the metal gets. You see this in body work on an auto all the time. They can only repair a fender by beating it back into place "so much" before they either have to replace the fender (or part of a quarter panel or etc.) as the metal will not "work" - go back into shape without tearing. You should have seen what I had to do to an Internation scout years ago. The fenders were AFU, and that is all I had to work with. After a lot of pulling and many metal tears, on went the bondo. That was the only Battleshop Grey Scout in the area. But, I digress.

For the rim, putting it back into round is a matter of degrees. If there is little deformation and a fairly thick STEEL rim, the rim could be worked back into round, but it will undergo some work hardening. If it is an aluminum rim, then you have a different problem as aluminim does not work like steel. It is likely to fracture (tear) by working it back into shape, unless, again, the deformation is small. I have an aluminum road wheel some 20 years old with just such a deformation. It still is fairly round, but not totally round. Still works but I don't use the bike much anymore.

But, after the wheel is back into round be it steel or aluminum, the area that was flattened and reshaped is work hardened. It is much more brittle than the areas around it. It will fail easier than the rest of the wheel. Again, it is relative to the amount of deformation that took place.

How would you shape it? you need a form or mandrel to work it against to return it to shape. If the wheel is a urban beater that just has a small deformation, I would just true it up as best as possible and use it as is. If there is a large flat, I would toss the wheel. If the wheel is round but the flat is just on the sides that the wheel clinches to, get out the pliers and straighten it some. Too much and you can have a break from work hardening.

If the wheel is not a single-walled one, I would toss it. It is my opinion that you cannot reshape a complex cross-section wheel with any hope of it being reliable.

Of couse, I could be full of sh$t also, please consider that. Take it to a local wheel guy with some experience and get his opinion.

Hope this helps.

Rick
If it's a steel rim throw it straight in the bin. Last time I saw a steel rim was on a £59 special down the local supermarket
 

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Discussion Starter · #11 ·
It's a Sun Rhyno Lite with an XT hub, and what looks to me like 14g spokes when compared to my 15g other wheelset. I thought Rhyno-lite rims are reasonably strong? I actually bought this wheelset on Ebay, i can't see myself flatting a rim that bad.

I guess once i get my bike built up, i'll ride it, hopefully it's not too bad, and if it is, get a new rear wheel. Thanks a lot for all the information, i really really appreciate it.
 

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BottomFeeder said:
It's a Sun Rhyno Lite with an XT hub, and what looks to me like 14g spokes when compared to my 15g other wheelset. I thought Rhyno-lite rims are reasonably strong? I actually bought this wheelset on Ebay, i can't see myself flatting a rim that bad.

I guess once i get my bike built up, i'll ride it, hopefully it's not too bad, and if it is, get a new rear wheel. Thanks a lot for all the information, i really really appreciate it.
replace the rim if you have a few spare bucks, Rhyno Lite or Singletracks don't cost a lot. If the spokes seem ok you should just be able to lace on the new rim.
 

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Ryhno Lites are OK. They are not big hit rims under some riders. Generally Sun Rims are on the soft side and tend to bend rather than crack. The RL is also notorious for being very difficult rims to mount and remove tires.
 
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