Cycling UK Forum

I have my Cube Stereo 160 e-bike. It’s full suspension, Bosch CX motor and 29” wheels. Lovely
1200 km of riding 9 months old. I weigh 80kg. I’m near 60 years old and don’t do jumps or huge drops.

After today’s ride I discovered another broken spoke. Actually, it’s not the spokes it’s the nipples that either pull through the rim or snap. My local shop gave me a handful of nipples and each time they break I have replaced them.
But at what point, do I ask for the wheels to be rebuilt?

I don’t want to be one of those impossible customers but if a wheel fails . . .

If you are breaking nipples its usually because the spokes are too short. There needs to be a good length of spoke inside the nipple, (ideally it should come to the bottom of the screwdriver slot in the nipple) and the strength of the spoke supports the load, not the nipple.
If the nipples are "pulling through the rim" then the rim has failed and you can't repair it simply by replacing the nipple.

In any case, multiple failures in under a year is "not of merchantable quality" and you should be offered either total replacement or a competent repair, at your option, I believe, but I'm not expert in consumer law.

Thank you for that comment. Yes, it could be that the spokes are too short. It can be v difficult to reconnect a new nipple.
I think I have to go back to the shop. My understanding of consumer law, is that they can offer a repair, I.e a rebuild (which I would accept if they have the skill).

Peel back the rim tape and have a look. You should be able to see the end of the spoke inside the nipple, or even if you can't, have a feel with a bit of thin wire, or a paperclip.

I Would say 2 broken spokes is too many. Whatever the reason a wheel that keeps breaking spokes needs to be rebuilt. New spokes at the very least.

531colin wrote: ↑4 Feb 2024, 5:29pm ...
In any case, multiple failures in under a year is "not of merchantable quality" and you should be offered either total replacement or a competent repair, at your option, I believe, but I'm not expert in consumer law.

I agree that this isn't acceptable..

Keep written dated records of all failures and all correspondence. This might become important.

Jonathan

the other thing that greatly shortens nipple life expectancy is if the nipples are not drilled concentrically. The spokes need to be too short too, but nipple wonkiness can help to hammer in the final coffin nails. If this is a factor, you will probably see it in the nipple fracture faces. Spokes being way too short is, sadly, relatively commonplace. However if you see failures when the wheel is very young, it may well be that the nipples are duff too.
btw nipples cannot normally pull through a rim without there also being some serious damage somewhere. Hopefully it is just the nipples breaking but if it isn't then the rim might be damaged, too.

Brucey wrote: ↑4 Feb 2024, 8:16pm ...
Hopefully it is just the nipples breaking but if it isn't then the rim might be damaged, too.

I wondered about that. You might need an expert opinion on this.

Jonathan

I think I have learnt something from this discussion.
The two symptoms of nipples, breaking and of nipples pulling through the rim could be for the same reason. And that reason is the spokes are too short. A short spoke doesn’t support the length of the nipple. And it also allows the nipple to contract in the rim because there’s no core in their hole.

Back to the shop I go. It’s not safe and both wheels need rebuilding or replacing.
Thank you for the comments.

I have seen very very few nipples pull through the rim, in a very long cycling lifetime.
The few I have seen have been from rim failure, not nipple failure.
Don’t suppose you could do a picture of what’s happening to yours?

Could your problem be aluminium nipples? I note from this site https://www.cube.eu/uk-en/cube-stereo-h ... bad521261d that Cube Stereo 160 use Newmen Performance 30 wheels. Investigating these wheels suggests that at least some are built using aluminium nipples https://www.bike-discount.de/en/newmen- ... ront-wheel.

I have limited experience of aluminium nipples, apart from a friend who had to have her wheels rebuilt, but they are "Not recommended for hardcore use, as aluminium nipples are not strong as regular brass".

If you lift the rim tape, you can check if the spokes are the correct length. The ends of the spokes should be level with the slot in the head of the nipple, as in the photo below. If the spokes are too short then you are more likely to have the nipples breaking because the head of the nipple is not being supported by the spoke.

Aluminium nipples are notorious for cracking off if spokes are too short. They need the spoke to reinforce them and there is a stress raiser where the diameter increases. The spoke needs to reach above this point. There's nothing wrong with them if this is done.

Redrhino wrote: ↑5 Feb 2024, 7:14am Back to the shop I go. It’s not safe and both wheels need rebuilding or replacing.
Thank you for the comments.

It's still worth doing as suggested above and checking the spoke lengths. Your right to choose how the matter is resolved only lasts for the first six months. The more informed you are when you take it in, the better.

ONE