Catastrophic spoke failure. While stored..

[Trikeyohreilly]

Hi. I had a dynamo hub wheel custom made for me last year. It did about 300 miles without any complaints before going into storage for the winter. Went to move it today and half the spokes on the disc side of the wheel have snapped. All the broken spokes are not only on the same side of the wheel but next to each other for half of it.

Is that sufficient information (without photos yet) to have a guess as to the cause? I've never seen anything like it.

Thanks.

[alexnharvey]

Where did they break? Ie at what point along the spoke, elbow, nipple, mid-section?

Have both sides of a pair of crossing spokes broken, or is it only spokes go the same direction from the hub to the rim either leading or trailing (that is, the spoke end goes forward from the hub to the rim or the end goes backwards from the hub to the rim.)

[nigelnightmare]

^^^ Wot E said.^^^
It sounds like it was over tensioned when built.

[Brucey]

what kind of spokes were they?

FWIW if there was road salt on the spokes, they may have suffered SCC (Stress Corrosion Cracking) whilst in storage.

cheers

[Trikeyohreilly]

Non at the elbow or nipple. They vary between an inch from the hub to three inches from the rim. But mostly near the middle of the spoke. Sorry, I should have added that originally.

[Trikeyohreilly]

I probably should know what type of spokes but have always left that to the wheel builders as I wouldn't know what to specify. They went into storage towards the end of September so no salt on the roads here then. At least they were not out salting.

[531colin]

Well, that's truly odd!
Sapim spokes have "SAPIM" stamped into them at the elbow end.
ACI spokes have a "V" on the spoke head, DT have "DT" on the spoke head, although it at first looks like a Chinese character.
For comparison, this is a ductile failure in a spoke..https://www.flickr.com/photos/52358536@N06/9633771211/in/album-72157624571269648/. A fatigue crack will give a failure surface like you get if you bend a carrot until it snaps, ie. angular.

[Brucey]

there will be a mark at or near the head of the spokes indicating their origin. Are they butted spokes?

What is the storage space like?

cheers

[Trikeyohreilly]

The spokes have an A on the heads. The storage space is spare room (unheated but never below say 10 degrees C). I have noticed that all the breaks are diagonal rather than perpendicular to the spoke.

[Trikeyohreilly]

OOOO/ /OOOO if that make any sense.

[alexnharvey]

Probably alpina spokes? http://www.mrrabbit.net/docs/spokeheads/main.html

[Trikeyohreilly]

The A on mine are raised like that but seem to fill the head of the spoke more completely being further to the edge of the head. I guess all the money went into the Alfine dynamo hub.

[NUKe]

Are you sure someone hasn’t cut the spokes bored teenagers/prankster friend ? or perhaps run over the wheel, parked against it. Would have thought over tensioned spokes would cause a couple of spokes maybe but once 1 or 2 break the wheel would loose tension so the rest wouldn’t break at this point.

[531colin]

So much for my memory/eyesight!
Yes it is an "A" on ACI spokes....although my excuse is that the cross line is rather high up! The spoke head is noticeably flat, other spokes tend to have a domed head.
Is "Alpina" just a bit of branding, ACI the manufacturer? I had forgotten ACI used to have an "S" on the head!

[Jamesh]

Spooky!!! sorry!!!