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Old 07-31-11, 05:44 PM   #1
Plimogz
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Any point in trying to adjust spokes on opposite side of the wheel?

Hey. I've wondered for a while now if there's any method to trying to adjust the tension of spokes which are far away from whatever it is that I'm trying to correct?

Like, if there's a hop in the wheel, with the rim going in towards the hub, but the tension in the spokes all around the hop is already lower than anywhere else on the wheel, could I add (very little) tension in many other spokes in some kind of pattern to pull in the rim elsewhere, and thus push it out at the inward hop? Or maybe pulling the rim to left on one side of the wheel to get some pull to the right on the opposite side?

It seems like there should be cases where this is desirable given a rim which isn't quite perfectly centred and aligned on the hub. (which is the point of the exercise, I guess)

Edit: this is assuming a best case scenario with a nice round, flat rim.

Last edited by Plimogz; 07-31-11 at 06:01 PM. Reason: perfect rim
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Old 07-31-11, 06:23 PM   #2
SBinNYC
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if there's a hop in the wheel, with the rim going in towards the hub, but the tension in the spokes all around the hop is already lower than anywhere else on the wheel,
That's usually indicative that the flat spot is cause by a bent rim and not due to spoke tension.

There are some tools that remove the low spot by bending the rim. Here are two:

http://www.biketoolsetc.com/index.cg...item_id=CU-014

and

http://www.biketoolsetc.com/index.cg...item_id=CU-030

These shop tools cost more than replacing the rim and do not give as good a result. The field repair used to be to take a belt, wrap it through the wheel at the low spot (closest to the hub) and wrap it around something substantial like a tree or utility pole. Then pull the dent out by gripping the hub and pulling the wheel. The leg muscles, not the back muscles, were used. This usually meant lying on ones back pushing with one's feet.
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Old 07-31-11, 06:25 PM   #3
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Originally Posted by Plimogz View Post
Like, if there's a hop in the wheel, with the rim going in towards the hub, but the tension in the spokes all around the hop is already lower than anywhere else on the wheel, could I add (very little) tension in many other spokes in some kind of pattern to pull in the rim elsewhere, and thus push it out at the inward hop? Or maybe pulling the rim to left on one side of the wheel to get some pull to the right on the opposite side?

It seems like there should be cases where this is desirable given a rim which isn't quite perfectly centred and aligned on the hub. (which is the point of the exercise, I guess)

Edit: this is assuming a best case scenario with a nice round, flat rim.
If you have a "nice round, flat rim" you should be able to have a nice round true wheel. It is important to work on radial true while bringing up the spoke tension evenly all around the wheel. It is possible to have even tension with a perfectly round rim and still have an out-of-round wheel. This is why it is important to concentrate on radial true early in a wheel build.
If you plan on doing much wheel work you need a truing stand and a tension gauge.
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Old 07-31-11, 06:30 PM   #4
Plimogz
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Yeah, I have the tools. Buying them cost a bit, but took practically no time. Getting good results with them however, is turning out to be very much the opposite: Cheap, but wonderfully time-consuming.
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Old 07-31-11, 06:38 PM   #5
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Originally Posted by Al1943 View Post
If you have a "nice round, flat rim" you should be able to have a nice round true wheel. It is important to work on radial true while bringing up the spoke tension evenly all around the wheel. It is possible to have even tension with a perfectly round rim and still have an out-of-round wheel. This is why it is important to concentrate on radial true early in a wheel build.
If you plan on doing much wheel work you need a truing stand and a tension gauge.
taking hops out of tensioned wheels is such a pain in the ass. new bikes with 3-5mm hop in the wheels. ridiculous
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Old 07-31-11, 06:42 PM   #6
Plimogz
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new bikes with 3-5mm hop in the wheels. ridiculous
ouch. for real? that's awful.

Really, I'm not trying to correct big things here. Just trying to improve my skill by perhaps combining truing and tensioning by working with other spokes than those localised at whatever imperfection it is that I'm focused on. I have a far fetched plan of building up a good a wheel as I can and then systematically unscrewing some spokes to check what the effect on tension on the opposite spokes would be.

I'd have to be in a really, really enthusiastic mood to purposefully screw up a good wheel though. So as usual the easiest way is to query the vast combined knowledge of the forum.

Last edited by Plimogz; 07-31-11 at 06:50 PM.
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Old 07-31-11, 07:01 PM   #7
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yea trek is suspect number 1. their nebula branded wheels were terrible. im talking 3-5mm total deviation(high to low, so ~2mm+-). it looks terrible in the stand. felt wheels suck too on their cafe bikes. specialized is pretty good for the most part but sometimes a bad one slips through.
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