Too many broken spokes on handbuilt wheel

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hoogerbooger
Posts: 185
Joined: 14 Jun 2009, 11:27am

Re: Too many broken spokes on handbuilt wheel

Postby hoogerbooger » 16 Sep 2020, 11:39pm

I've had a similar issue before and am wondering if I suffered from a bad Sapim batch.

The only time I've had a front spoke break was a Sapim on a pretty new pair built by Spa. The pair had only done about 1500 miles and 3 spokes went on the back and one on the front.

(When the front spoke went I decided to get the LBS to rebuilt them, but they wouldn't because they just didn't like the Sputnik rims ( !!) so as I had a cycle tour imminent, I bought new spokes from the LBS and made my first set of wheels ( no truing stand then, just in the frame) ! Most of my wheels survive ok ( but I have had to rebuild a couple)

So I shall stop presuming it was a Friday afternoon trainee set that Spa sent me, and just be thankful I now how to rebuild wheels on tour/as needed.

mig
Posts: 2257
Joined: 19 Oct 2011, 9:39pm

Re: Too many broken spokes on handbuilt wheel

Postby mig » 16 Sep 2020, 11:43pm

i take it that the series of replacement spokes didn't break down the line? just the originals?

spokes like that must be substantially weaker than normal to break in the middle. i wonder if stress relieving them initially actually aids the process of them breaking?

Brucey
Posts: 40534
Joined: 4 Jan 2012, 6:25pm

Re: Too many broken spokes on handbuilt wheel

Postby Brucey » 17 Sep 2020, 7:36am

mig wrote:... i wonder if stress relieving them initially actually aids the process of them breaking?


no, absolutely not.

In the few cases of 'bad Sapim spokes' I have encountered in the flesh, the spokes are typically so badly embrittled that they will snap like a carrot when you take a loose spoke and try and bend it. By contrast good spokes are normally so ductile that you could reasonably expect to be able to tie a knot in one without it breaking; not so an embrittled spoke, you would have no chance.

Perhaps the OP can try a few bends in any (pieces of) old spokes that are available?

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

mig
Posts: 2257
Joined: 19 Oct 2011, 9:39pm

Re: Too many broken spokes on handbuilt wheel

Postby mig » 17 Sep 2020, 3:14pm

Brucey wrote:
mig wrote:... i wonder if stress relieving them initially actually aids the process of them breaking?


no, absolutely not.

In the few cases of 'bad Sapim spokes' I have encountered in the flesh, the spokes are typically so badly embrittled that they will snap like a carrot when you take a loose spoke and try and bend it. By contrast good spokes are normally so ductile that you could reasonably expect to be able to tie a knot in one without it breaking; not so an embrittled spoke, you would have no chance.

Perhaps the OP can try a few bends in any (pieces of) old spokes that are available?

cheers


methinks that i worded that badly.

i wonder if stress relieving the dodgy sapim spokes actually aids in the process of them breaking?

Brucey
Posts: 40534
Joined: 4 Jan 2012, 6:25pm

Re: Too many broken spokes on handbuilt wheel

Postby Brucey » 17 Sep 2020, 6:58pm

Ah, I see what you mean. I would say that if the spokes are bad (embrittled) they are too weak to use, too weak to stress-relieve, too weak for anything much at all, really.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~