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.