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[Closed] How strong are brass nipples?

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 Olly
Posts: 5169
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Built up some new, wider rims last weekend. All the spoke calculators gave me the same answers regarding spoke lengths, but one set has come up a bit short.
The spokes threads only just disappear into 14mm nipples, the Base of the spoke doesn't protrude past the nipple flange as with the others. (already increased these nipples to 14mm over the standard 12 to increase thread contact)
Using brass nipples, are these going to rapidly give up at the flange/stem transition, or is it only really am issue with rubbish alloy nipples?

Its a front wheel so should take less in the way of abuse,but greater torsional load under braking (203mm rotor).


 
Posted : 28/03/2017 3:34 pm
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Pretty sure you need 7 whole turns, or, the end of the spoke visible flush with the slot cut at least.

Edit- I'd rather have a rear wheel fold than a front one.


 
Posted : 28/03/2017 3:38 pm
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If you can't see the threaded part of the spoke then I'd say it's fine.


 
Posted : 28/03/2017 3:41 pm
 cp
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I've run wheels with a couple of threads on the spoke visible for years without problem.


 
Posted : 28/03/2017 3:43 pm
 Bez
Posts: 7371
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Here are the insides of 12, 14 and 16mm DT nipples. The other useful piece of information is that the spoke tension will be almost all distributed over the first (ie nearest the bottom of this image) six threads.

I suspect the upshot of this is that you've got enough thread engaged not to strip it, but you may have a bit more opportunity than normal for the nipples to fail at their flanges. Quite how likely that is or how soon it would occur under any given usage I don't know.

[img] [/img]


 
Posted : 28/03/2017 5:38 pm
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which spoke length calculators did you use?
have you checked you put the spokes in the correct side of the flange with the right number of crosses?


 
Posted : 28/03/2017 5:53 pm
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Yes, threads are designed with 'backlash' otherwise the friction would be too great to screw them on so 6 turns is plenty. Over-tensioned spokes are more likely to pull-through a rim than fail IME. Alloy nipples are far more prone to fatigue failure IME.


 
Posted : 28/03/2017 6:03 pm

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