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Old 07-12-2006, 01:27 PM
gone gone is offline
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Can this rim be saved?

A few weeks back I had a blowout at about 25 mph on the rear wheel and, before I could get stopped, hit a pretty decent pothole which knocked the wheel out of round and out of true. After a fair amount of work, the rim is once again true and round but the spoke tension is still out of whack. If you look at the attached photo, you can see that all are within +-5% with the exception of 7 on the drive side. Note also that spokes 7&8 on the non-drive side are also tight though they are within 5% of the rest of the non-drive spokes. Doing the "obvious" thing, tightening drive side spoke 7 and loosening non-drive 7&8 takes the wheel out of true (pulls toward the drive side). Any suggestions on how to get the spoke tension right from you wheelbuilders out there? In case it's not obvious, this is the area of the rim where I hit the pothole, the very edge of the rim (above the braking surface) has a notch in it right above spoke 7.

Thanks for any suggestions.
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Old 07-12-2006, 01:51 PM
Jeremy Jeremy is offline
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no

Your rim cannot be saved. For a wheel to be true and have acceptable uniform tension, the rim has to be round and straight to start with. If you remove all of the spokes and place the rim on a flat surface, it would not lie flat. Get a new rim and rebuild. If it is not too old, you may be able to re-use the spokes.

Jeremy
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Last edited by Jeremy; 07-13-2006 at 09:32 AM.
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Old 07-12-2006, 02:47 PM
KevinK KevinK is offline
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Quote:
Originally Posted by Jeremy
Your rim cannot be saved. For a wheel to be true and have acceptable uniform tension, it has to be round and straight to start with. If you remove all of the spokes and place the rim on a flat surface, it would not lie flat. Get a new rim and rebuild. If it is not too old, you may be able to re-use the spokes.

Jeremy
Not necessarily. It depends on what the wheel will be used for. I don't believe the tension is so far off that catastrophic failure of the wheel is eminent. So, if the OP is using the wheel for commuting and doesn't mind having to retrue it occasionally, I say use it. On the other hand, if the OP is using it for racing or loaded touring, replacing it would be prudent.

When I used to work in a bike shop (LONG ago) we used to "straighten" these potato-chip rims by inflating the tire on the rim, detensioning the spokes in and adjecent to the damaged area, and then smacking the side of the tire in area of the bend it crisply on the concrete. We had much better luck fixing sideways bends in this manner than trying to pull rims that were bent in towards the hub.

Kevin
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Old 07-12-2006, 02:56 PM
Jeremy Jeremy is offline
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Quote:
Originally Posted by KevinK
Not necessarily. It depends on what the wheel will be used for. I don't believe the tension is so far off that catastrophic failure of the wheel is eminent. So, if the OP is using the wheel for commuting and doesn't mind having to retrue it occasionally, I say use it. On the other hand, if the OP is using it for racing or loaded touring, replacing it would be prudent.

When I used to work in a bike shop (LONG ago) we used to "straighten" these potato-chip rims by inflating the tire on the rim, detensioning the spokes in and adjecent to the damaged area, and then smacking the side of the tire in area of the bend it crisply on the concrete. We had much better luck fixing sideways bends in this manner than trying to pull rims that were bent in towards the hub.

Kevin

True enough, the wheel can still be ridden and its' intended use is important. I have made many damaged wheels rideable by bending the rim itself into a nearly straight condition and retruing. My point was that it seems that his wheel is already in a "not right, but still rideable condition". It is unlikely that the wheel could be made much better without replacing the rim.

Jeremy
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Old 07-12-2006, 05:16 PM
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Thanks Kevin and Jeremy for the replies, they pretty much confirmed what I'd already suspected but I thought what the heck, someone might know something I don't know that would make it "good as new".

The wheel is for general purpose riding, not racing or touring, and I don't mind retruing occasionally. I'll probably replace it sometime in the future but will continue to ride it for a while 'til I get around to it.
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Old 07-13-2006, 08:31 AM
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Too Tall Too Tall is offline
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What Jeremy said...it will never be right. Replace the rim.
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