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Old 07-10-12, 04:07 AM   #1
dabac
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High spoke tensions - when do I start running the risk of stripping nipples?

Hi guys,

I'm having my first real experience with low spoke count wheels, a Mavic Ksyrium Elite, a 20-spoke rear.

I'm finishing up a rim swap and I'm a bit concerned about the final tensioning. According to the spec, I should shoot for 140-160 kg of tension. Which although being some ways off still, is beginning to make the nipples kinda stiff to turn.

I've seen people pushing the rim sideways to unload the spokes before turning the nipples on low-count wheels, but my regular trueing stand is way too flimsy for that.
So:
- do I need to bungle up a more rigid trueing stand for the final stages of tensioning?
- should I just go ahead, in the traditional manner?
- should I (the horror!) try to track down a bike shop / mechanic that'd actually have a chance of doing it properly?

Cheers,
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Old 07-10-12, 04:52 AM   #2
reptilezs
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i usually do new spokes on ksyrium rim swaps. the nipple are seized half the time
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Old 07-10-12, 08:47 AM   #3
dabac
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Originally Posted by reptilezs View Post
i usually do new spokes on ksyrium rim swaps. the nipple are seized half the time
Had two seized nipples, that's sorted now.

What about tensioning? Do you just keep turning the nipples or do you push the rim sideways to relieve tension while turning the nipples?
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Old 07-10-12, 09:12 AM   #4
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Greasing the nipple where it contacts the rim will help, if you didn't do that already.
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Old 07-10-12, 10:00 AM   #5
dabac
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Originally Posted by mechBgon View Post
Greasing the nipple where it contacts the rim will help,
Done that, still unnervingly stiff. Can't/don't like to lube the threads, as the nipples have nylock inserts.
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Old 07-10-12, 12:29 PM   #6
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Done that, still unnervingly stiff. Can't/don't like to lube the threads, as the nipples have nylock inserts.
You _really_ should. 130kgf isn't a problem that way with 2.0/1.5 spokes and alloy nipples and there's room to go higher (I haven't needed to).

With enough tension properly lubricated spoke threads/nipple sockets (I'm partial to anti-seize applied with an acid brush that's had half its bristles cut off) have plenty of friction to prevent rotation.

"Enough" is the uniform 45-50kgf you have in the non-drive side when you lace a Campagnolo hub to a shallow box section rim at 110kgf drive side.

The nylock inserts are only useful for companies that'd like to sell nipples for more than $0.13 each, as some sort of other marketing exercise (Our wheels use patented Ultra-Mega-Nipples), with fast machine truing that won't get sufficiently uniform and high non-drive side tension to keep the loosest spokes from getting looser, perhaps in machine built wheels which haven't had the windup taken out (I don't know if the insert is tenacious enough for that), or where you're doing something you shouldn't (certain very light tubeless rims have a low tension rating and loose about half their tension when a tubeless tire is installed).

Otherwise they're working against you with the added friction increasing windup and you'd be better off if your grease dissolves them (not going to happen) or otherwise renders them less effective.

Last edited by Drew Eckhardt; 07-10-12 at 01:49 PM.
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