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Spoke torsion question

Old 06-17-11, 09:22 AM
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serpico7
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Spoke torsion question

Sheldon Brown's wheel building article talks about eliminating the twist in spokes by turning the nipple a little further than you need, and then backing off by the same amount.

I'm just about done tensioning a wheel, but didn't bother with backing off each time I turned a nipple.

1. Can I just go around the wheel and tighten each nipple a 1/8 turn and then loosen 1/8 turn and solve the torsion issue that way?

2. Is that even necessary? Does squeezing pairs of spokes (e.g., 1 & 3; 2 & 4, etc.) pretty much eliminate the torsion?
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Old 06-17-11, 09:37 AM
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Different spokes twist different amounts, with 2mm plain gauge spokes twisting the least, and spokes with sections of 1.5 or 1.6 in the middle twisting the most. Thread friction which in turn is affected by lube/spoke prep and tension is also a factor.

All in all you could expect that 2mm spokes on the left rear will barely twist at all, while light spokes on the right rear will twist like candy canes.

Once there's already twisting, your method of adding and removing twist will only get back where you started. You need to maintain zero twist as you go along, or flex the wheel enough to relax tension on spokes so they straighten naturally, which is what causes the pinging you hear when stress relieving the build.

Getting rid of twist is important because otherwise the spokes will untwist on their own as you ride throwing the alignment off. This is the characteristic pinging you often hear when newly built wheels are first ridden.

Here's a trick which can help, for future reference.

Lace up the wheel and do the pre-tightening, then if the wheel is reasonably true, spin the wheel holding a dry marker to the spokes above the nipples. (If it's too far off for this, rough true it in the semi loose condition) Do both sides, leaving a black dot on the outside of each spoke. If you miss any, do those one at a time. Now you'll have a fixed reference for the untwisted position of each spoke, and can monitor and correct twist as you tighten. Note that you have to mark the spokes before any are tight enough to start twisting.
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Old 06-17-11, 09:38 AM
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I usually stress relieve the wheel by laying it on the ground, placing my hands at 3:00 & 9:00, and leaning on it a bit, rotate 1/3, repeat (twice), then flip the wheel over & repeat. You'll probably hear a few pings & pops as the spokes untwist.
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Old 06-17-11, 10:05 AM
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Originally Posted by FBinNY View Post
Here's a trick which can help, for future reference.

Lace up the wheel and do the pre-tightening, then if the wheel is reasonably true, spin the wheel holding a dry marker to the spokes above the nipples. (If it's too far off for this, rough true it in the semi loose condition) Do both sides, leaving a black dot on the outside of each spoke. If you miss any, do those one at a time. Now you'll have a fixed reference for the untwisted position of each spoke, and can monitor and correct twist as you tighten. Note that you have to mark the spokes before any are tight enough to start twisting.
Neat trick, thanks.
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Old 06-17-11, 10:06 AM
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Originally Posted by Homebrew01 View Post
I usually stress relieve the wheel by laying it on the ground, placing my hands at 3:00 & 9:00, and leaning on it a bit, rotate 1/3, tepeat (twice), then flip the wheel over & repeat. You'll probably hear a few pings & pops as the spokes untwist.
Perfect. A lot easier than trying to figure out how much twist is in each spoke and undoing it.
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Old 06-17-11, 10:35 AM
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Originally Posted by Homebrew01 View Post
I usually stress relieve the wheel by laying it on the ground, placing my hands at 3:00 & 9:00, and leaning on it a bit, rotate 1/3, repeat (twice), then flip the wheel over & repeat. You'll probably hear a few pings & pops as the spokes untwist.
Me too, but be reasonable about it. You can easily taco a wheel this way if you over-do it.
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Old 06-17-11, 10:37 AM
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Stress relieving near the end of the build is a standard and necessary practice, but does not effectively eliminate 100% of the twist, as anybody who ever built wheels using oval (aero) spokes will attest.

The other problem is that as the spokes untwist, some will take the nipples with them which is desirable, but others will untwist within the nipple, which means an extra step tuning up the alignment. Also this is less effective on right rear spokes which are usually too tight to untwist themselves by this method.

It's still good practice as a final check, and if done well will eliminate the need to tune up a wheel after riding a short while.

But best practice is not to introduce twist in the first place. The dot method works well by giving you a reference, but with some experience you can skip it, or use it only as a final check. Experienced wheel builders prevent twist by feel. As the nipple is turned, spokes will first twist then when the torsion exceeds thread friction the nipple will turn. You can feel (and hear) the point when this happens, and correct for it as you go along.
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Old 06-17-11, 10:51 AM
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By using lots of lube on the threads and on the nipple where it sits against the rim, will really help. You really cannot over lube this as once tension is up and no wind up, stress relief done, they will not unwind.
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Old 06-17-11, 02:28 PM
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My spokes don't twist because I hold each spoke with pliers. Soft jaw pliers are available if you're worried about scratching the spokes. I just use cheap plain old pliers and my spokes have no marks on them. Been doing it this way for at least 10 years.
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Old 06-17-11, 03:39 PM
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Originally Posted by serpico7 View Post
Sheldon Brown's wheel building article talks about eliminating the twist in spokes by turning the nipple a little further than you need, and then backing off by the same amount.
Pieces of tape on representative spokes (front, rear drive-side, rear non-drive side; I like the spoke(s) following the valve stem hole) will let you see what's going on in that wheel and compensate appropriately.

You can feel it (where the nipple takes the same torque to turn in both directions there's no more windup) but that's more of an acquired skill.

I'm just about done tensioning a wheel, but didn't bother with backing off each time I turned a nipple.

1. Can I just go around the wheel and tighten each nipple a 1/8 turn and then loosen 1/8 turn and solve the torsion issue that way?
No. It might be more or less than 1/8 turn.

2. Is that even necessary?
Yes. Otherwise the wheel will probably make popping noises the first time you ride it and go a little out of true.

Does squeezing pairs of spokes (e.g., 1 & 3; 2 & 4, etc.) pretty much eliminate the torsion?
No. Stress relieving increases tension.

You can set the wheel on the ground on its axle (put a block of wood under the axle to save your floors) and go around the wheel pushing on opposite sides thus reducing tension on the spokes near the ground. Flip it over and do the same for the other side.

Last edited by Drew Eckhardt; 06-17-11 at 03:42 PM.
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Old 06-17-11, 03:41 PM
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Originally Posted by deacon mark View Post
By using lots of lube on the threads and on the nipple where it sits against the rim, will really help. You really cannot over lube this as once tension is up and no wind up, stress relief done, they will not unwind.
DT 2.0/1.5 Revolutions lubricated with anti-seize wind up about 1/4 turn drive-side and 1/8 turn non-drive side as you reach 110-120 kgf drive side tension.
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