Broken spokes

[pliptrot]

I've broken spokes before (light weight rims like Open Pros), and it was always a mess as the rim went straight out of true. I have a Nihola cargo bike, which has 2 20" wheels up front and a 26" wheel behind. (36 spokes). Last week I found a broken spoke on the rear wheel. At the nipple. It stayed true. Expediency being what it is I used the bike for a few more days to take my daughter to school. Now I've got another broken spoke 180' from the first. Nipple end again. Stayed true again. So the question is, when I take the wheel to the LBS (I can't imagine being able to buy 2 spokes and 2 nipples myself) should I ask them to replace the 2 spokes or to rebuild the wheel? I'm in Germany so asking for an opinion will likely draw blank faces. The decision will be what I tell them after I have asked you lot for an opinion.

[MartinC]

I'm sure Roseversand will sell you spokes and nipples in small quantities. They certainly did in the good old days when we could easily buy goods from Europe from behind the sanctity of the UK borders.

[alexnharvey]

You should aim to determine the cause of the failures. For example, if the spokes are slightly short the nipple can fail by cracking off the head. If so then you are likely to need to replace all spokes with longer ones. Or, if it's a problem with the stress relief and/or spoke path not being set correctly, the spoke will fail through fatigue.

My experience is that once two go, you have a pattern that is likely to continue. It depends on your patience whenever you are willing to continue to replace those that crack as they go, and the consequences of further failures, which may not be too drastic if the wheel continues to remains true enough to ride. If you are paying someone to do it is very likely to be less costly to have them all done at once. If the wheel remains true then it's quite possible to take yourself.

You should certainly aim to correct the spoke path and stress relieve the wheel, or be sure that the lbs know to do this.

[sukuinage]

I'm sure Roseversand will sell you spokes and nipples in small quantities. They certainly did in the good old days when we could easily buy goods from Europe from behind the sanctity of the UK borders.

Yes, Rosebikes.de as it is now will sell you individual spokes. You'll need to know the length; there are calculators online if you know the hub and rim

[Jupestar]

I'd just chuck the wheel at them and ask them to sort it.
Make sure they priced in a service / tensioning / retrue after the spoke replacement.

My LBS has a really good wheel builder who knows his stuff. I've no doubt he would re tension the wheel anyway, after adding the spokes, but I'd ask him to do it and accept paying a bit extra for it. My view is always get these things done ASAP before the problems grow.

I surprised you think they will want a fuller description for repair. When I was in Italy I had a lightweight wheel go in the same way, popped in large but independent shop to see if they could help. I went into the workshop and it was full of E-bikes, with the E-bikes plugged into what i assume was diagnostic testing machine for each brand. The mechanic saw my wheel and noticeably perked up. spoke to me in German (northern Italy) I did not understand, but no matter as he already had it in the wheel stand, 10mins later it has a new spoke, re tensioned and trued. And he charged be about €10. Then he went back to his backlog of E-bikes..

[mig]

I'd just chuck the wheel at them and ask them to sort it.
Make sure they priced in a service / tensioning / retrue after the spoke replacement.

My LBS has a really good wheel builder who knows his stuff. I've no doubt he would re tension the wheel anyway, after adding the spokes, but I'd ask him to do it and accept paying a bit extra for it. My view is always get these things done ASAP before the problems grow.

I surprised you think they will want a fuller description for repair. When I was in Italy I had a lightweight wheel go in the same way, popped in large but independent shop to see if they could help. I went into the workshop and it was full of E-bikes, with the E-bikes plugged into what i assume was diagnostic testing machine for each brand. The mechanic saw my wheel and noticeably perked up. spoke to me in German (northern Italy) I did not understand, but no matter as he already had it in the wheel stand, 10mins later it has a new spoke, re tensioned and trued. And he charged be about €10. Then he went back to his backlog of E-bikes..

had a similar story from two friends who went 'touring' near Barcelona on very old bikes. one broke a rear wheel DS spoke fairly quickly then tried/failed to fix it himself. they found what was described as a "bike shop like a posh car showroom," entering with faces and hands covered in grime expecting to be ushered out. instead they fixed it for a reasonable sum and on they went

[Vorpal]

I would take it to the LBS & ask them to replace the broken ones & check the wheel over.

Chances are the second one broke because of the first, but it's possible that there is a problem with spokes or wheel.

If the bike is relatively new, it could be that a machine built wheel hasn't been properly stress relieved. Your LBS or a wheel builder can do this for you.

Here are a couple of previous threads. The second includes an explanation of stress relief.

viewtopic.php?t=145491

viewtopic.php?f=5&t=110419

[531colin]

Have the nipples broken or the spokes?
If the spokes are breaking where they emerge from the nipples then the wheel hasn’t been effectively stress relieved or the spoke line corrected. …unless the thread emerges from the nipples, which means spokes are too short.
A good thread linked above re. Stress relief

[Stradageek]

In my experience, machine built wheels are often nice and true but rarely exhibit even spoke tension. A wheel with an adjacent pair of spokes that are respectively too tight and too loose will run is just as true as one with adjacent spokes evenly and correctly tensioned but will be much more prone to breakage. I have always re-tensioned any wheel I've obtained to make sure this error is fixed and have never had a broken spoke since.

Though it is possible that the other faults listed above may be the the cause, my first suggestion would be to replace the broken spokes then get the wheel 'evenly' tensioned.

As a final suggestion, do try and get the wheel sorted ASAP. If the wheel goes out of true it will likely 'bend' the rim requiring uneven spoke tension to pull the wheel back into true and resulting in a propensity for the high tension spoke(s) to break again.

Hope this helps

[531colin]

Spokes fail through fatigue.
Fatigue happens where the spoke flexes; if the wheelbuilder sets the spoke to the correct angle and stress relieves, the fatigue life of the spoke is long enough that spoke failure isn’t something you need to be concerned about.
I think somebody already said, even if some spokes are already (fatigue) cracked, you can still set the bends properly, stress relieve the wheel, and expect only a few more spoke failures.
A shop is unlikely to do this, because I never wanted my reputation as a wheelbuilder to be based on the mistakes the previous builder made.

[Valbrona]

Only rebuild the wheel if the existing spokes, or some of them if there are different sized spokes in the wheel, are the wrong length.

Inspect to see just how much spoke is poking through the end of the nipples. Too much and the spokes could be too long, so that the nipples are bottoming out on the spoke threads.

Threads will be visible on some spokes if they are too short - not enough threads are engaging into the nipples.