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I have a professionally-built Rohloff wheel, 32-spoke, symmetrical, laced to Velocity Dyads with Sapim Race spokes, disc brakes. It is about six years old, built in 2011; but I mostly just use it when I go touring, so only about 5,000-6,000 miles on it. Always seemed very true, never wrecked, no unusual events.

On a recent tour, a spoke broke while I was stopped, eating lunch. I replaced it and tried to match its tension to the other spokes by tone-when-plucked. Next day, another spoke broke while riding on smooth pavement. I'd only had one spare spoke, so I rode for another kilometer or so minus one spoke, but that really put the wheel out of true. I walked until I found a kindly stranger gave me another 2mm straight-gauge spoke of about the same length.

When I put that replacement in, I de-tensioned all the spokes by about half a turn (thinking "maybe these spokes are too tight"), very carefully tried to equilibrate tension on all of them by tone, and trued out the deflection caused by riding minus one spoke. I finished the tour, maybe another 550 miles, like that, no more spoke breaks.

I'm going to re-spoke the wheel -- I don't trust any of the spokes in it anymore. But I'm also trying to determine a cause here. I don't want to have this happen again. Other points:

  • Rohloff pointed out that there was a bad batch of Sapim Race spokes at one point. Sapim says that batch was not in 2011, when these wheels were built (various internet posts make it look like that was 2014).
  • Rohloff support was like "sounds like a spoke problem, can't help you." (fair enough)
  • Sapim was like "doesn't sound like a spoke problem, can't help you" (no I don't understand that logic either)
  • My wheel builder has a good reputation but for whatever reason has not been responding to calls or emails, so no information there.
  • The breaks are 6mm and 13mm from the neck bend. So around the hub flange. Pictures below; I lost one of the spoke heads.

Any ideas on cause? My initial theory was that it was built too tight, but most advice online (and Rohloff support, and Velocity support who I also emailed) says that'd be unusual. I guess I just can rebuild and hope for the best, but it would be nice to have some sense of causation so as to prevent this from happening again.

Spoke break from afar Spoke break position up close Spoke break macro

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    I've never seen a spoke break the way the top one broke before, so I'd suspect that was a bad spoke. A little harder to say about the bottom spoke. Typically the spoke breaks at the nipple or right at the head. – Daniel R Hicks Aug 29 '17 at 23:26
  • It's possible that the way the spokes were laced had two of them crossing at the point where the top one broke. In that case, flexing would have been the cause. – Daniel R Hicks Aug 30 '17 at 3:17
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    There are strange scratches near the breaking point. Those may have been a starting point for the crack. Spokes usually don't break at that point. – ojs Aug 30 '17 at 8:40
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    Looks a bit close to the elbow to be a crossing point. Are any of the other spokes scored in the same place? It's pretty easy to get scratches there if the chain drops onto a moving wheel. Oh, and that breakage pattern (part smooth+discoloured and part rough) looks like a classic fatigue failure, where a crack grows slowly until the remaining metal is weak enough to snap. – Useless Aug 30 '17 at 12:42
  • I don't see any scratches on it, in the pictures or in person; I think what you may be seeing is a reflection. It is a two-cross, so the breaks are near the first cross, but the spokes don't touch there. Other spokes look pretty shiny, no systematic scoring or damage at this point to the others. – joseph_morris Aug 30 '17 at 20:19
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I've broken a spoke on a well-built wheel simply from hitting a bump in the road a little too hard. And on a generic wheel, I've seen that when one spoke breaks, the spokes at 90° intervals from it start breaking, even after I replace the first broken spoke. My guess is that this reflects a pattern of underlying stresses. So neither of your spoke breaks surprise me that much.

Since this is a Rohloff hub, you shouldn't have super-high tension on just the drive side due to dishing, so we can rule out that frequent cause of spoke breakage.

It might be fatigue. Jobst Brandt regarded fatigue failures as a consequence of failing to stress-relieve the spokes when the wheel was built.

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Could be a lacing issue or even try a different pattern.

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    Please browse the tour to see how the site works. This answer is quite short, and while you're correct, it doesn't tell OP how lacing could be related, or what could be wrong with the current lacing pattern that would be fixed by another lacing pattern. Also, any other lacing pattern will probably require replacement spokes because of differing length, which requires rebuilding and retensioning, which is a complete rebuild. – Criggie Jun 7 '18 at 4:37

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