Broken spoke ...

[S.Giles]

I've been cycling for decades (on cheap bikes) and never broken a spoke!

Does the rim have eyelets by any chance? Eyelets can cause a bend in the spoke where it enters the nipple, due to the eyelet holding the nipple at the wrong angle. I've often wondered if this is the cause of some broken spokes. Reading other threads online tends to suggest it is. A large hub diameter would exacerbate this, BTW.

 

[Spoked Wheels]

It's not normal on well built wheels.

 

[ChrisV]

@S.Giles not sure about the technicalities, it's these ...

Rims: Whyte Disk Road 32mm Deep, Offset Section Rim, 32 Hole Rear and 28 Front, 3M Reflective Decals

Spokes: WTB 2.0mm, Black Sandvik Stainless with Black Brass Nipples
.

I got the bike in August. 4 broken spokes in 850 miles. Should I be having a discussion with the LBS about a replacement wheel under warranty or is this just par for the course?

 

[Tim Hall]

Another factor could be the weight of the rider. Are you a well nourished individual?

 

[ChrisV]

15 1/2 stones.

 

[S.Giles]

@S.Giles not sure about the technicalities, it's these ...
I got the bike in August. 4 broken spokes in 850 miles. Should I be having a discussion with the LBS about a replacement wheel under warranty or is this just par for the course?

Breaking spokes isn't par for the course!

Have a look at each spoke where it enters the nipple (the 'wee metal bit'). Is there (ever such) a slight angle on some (or all) of them? As if the spoke isn't making an exactly straight line with the nipple? If so, this angle could be the cause of fatigue in the spoke. Just a hypothesis, but a plausible reason why you'd be having problems.

I've just built a wheel with exactly this situation, and am nervously awaiting my first 'twang'!

 

[Tim Hall]

What's that in kilos? <fx: counts in fingers and toes> OK, 98kg. Heavier than me, but not too much I think for a 32 spoke wheel. I've got 32 spokes on my fixer and I'm 90kg at present (too many Easter Eggs). However, the rear wheel on my fixer is undished, which I understand is stronger. What say you @Spoked Wheels?

 

[Spoked Wheels]

What's that in kilos? <fx: counts in fingers and toes> OK, 98kg. Heavier than me, but not too much I think for a 32 spoke wheel. I've got 32 spokes on my fixer and I'm 90kg at present (too many Easter Eggs). However, the rear wheel on my fixer is undished, which I understand is stronger. What say you @Spoked Wheels?

Yes, you can ride a 32 spokes wheel at 98kg without problems I used to ride my 32 spokes wheel when I was 117kg and I never broke a spoke..... mind you, at that weight I was shortening the life of the wheel rapidly but I refused to build a 36 spoked wheel so I lost the weight instead. I'm in the high end of 80kg now,
Undished wheels are stronger laterally and less strong radially - overall they make stronger wheels. Same tension on both sides make a big difference.

 

[Spoked Wheels]

I've been cycling for decades (on cheap bikes) and never broken a spoke!

Does the rim have eyelets by any chance? Eyelets can cause a bend in the spoke where it enters the nipple, due to the eyelet holding the nipple at the wrong angle. I've often wondered if this is the cause of some broken spokes. Reading other threads online tends to suggest it is. A large hub diameter would exacerbate this, BTW.

Yes, it is a problem with very big hubs like the Shimano Alfine, having said that the spoke angle on those is rather extreme for a spoke maybe 83 or 84 degrees. 90* would be perfect and anything above86* is fine. I have studied the problem and lots of people suffer with broken spokes with the Shimano Alfine. I'm going to build a wheel with this hub so I have spent time reading and modelling and I think I found a way to improve things.
Rollof hubs ( not sure of spelling) recommend a particular rim to prevent spokes breaking because of the extreme spokes angle. The holes are positioned to improve the angle.

 

[S.Giles]

Yes, it is a problem with very big hubs like the Shimano Alfine, having said that the spoke angle on those is rather extreme for a spoke maybe 83 or 84 degrees. 90* would be perfect and anything above86* is fine. I have studied the problem and lots of people suffer with broken spokes with the Shimano Alfine. I'm going to build a wheel with this hub so I have spent time reading and modelling and I think I found a way to improve things.
Rollof hubs ( not sure of spelling) recommend a particular rim to prevent spokes breaking because of the extreme spokes angle. The holes are positioned to improve the angle.

Maybe a little judicious filing of the spoke-holes (or eyelets) is a good idea. A thin rat-tail file would work, although 36 spoke-holes would probably become somewhat tiresome! I have decided to give this a try if I ever get a broken spoke. I'm using a Shimano XT rear hub in a 26" rim, so the angles involved are not as extreme. The nipples are definitely not in a straight line with the spoke, though. This was particularly noticeable when tightening the nipples with the type of nipple-wrench I use, and is (just about) visible in the finished wheel.

The alternative, I suppose, would be to stress-relieve the spokes where they exit the nipple, so that they are not tending to flex back and forth on every revolution of the wheel.

 

[Spoked Wheels]

No, I wouldn't try filing the hole.

I don't understand why you would have a problem with an XT hub and a 26" rim. The flange diameter is about 60mm but the Alfine is more like 93mm so you can the spokes would be a lot shorter.

I like to bend the spoke into a better angle when I'm removing the slack. That seems to work well.

 

[S.Giles]

I don't understand why you would have a problem with an XT hub and a 26" rim. The flange diameter is about 60mm but the Alfine is more like 93mm so you can the spokes would be a lot shorter.

I'm just anticipating a potential future problem, due to the (admittedly slight) bend in the spokes at the nipple. There hasn't been a problem so far, but I've probably only ridden fifty miles or so on the wheel. I would ideally like to see everything lined-up as it is supposed to be (like it is on the front wheel, which uses a different rim sans eyelets).

Edit: The wheel is laced in a 4-cross pattern, which probably increases the spoke-to-rim angle a little.

No, I wouldn't try filing the hole.

The reason being?

 

[Spoked Wheels]

I'm just anticipating a potential future problem, due to the (admittedly slight) bend in the spokes at the nipple. There hasn't been a problem so far, but I've probably only ridden fifty miles or so on the wheel. I would ideally like to see everything lined-up as it is supposed to be (like it is on the front wheel, which uses a different rim sans eyelets).

Edit: The wheel is laced in a 4-cross pattern, which probably increases the spoke-to-rim angle a little.

The reason being?

4-cross pattern? How any spokes are you using? I've never used 4-cross pattern for 36 spokes or less but that is another issue.

The reason why I wouldn't try filing a rim hole. Well, most of the wheels I build are for other people so I would never take a risk that might put somebody in danger. It might be perfectly alright but I wouldn't do it.

If I thought the spokes on a XT /26" rim didn't look straight enough then rather than filing the spoke hole I would look at another rim or even review my building technique.

 

[raleighnut]

4-cross pattern? How any spokes are you using? I've never used 4-cross pattern for 36 spokes or less but that is another issue.

The reason why I wouldn't try filing a rim hole. Well, most of the wheels I build are for other people so I would never take a risk that might put somebody in danger. It might be perfectly alright but I wouldn't do it.

If I thought the spokes on a XT /26" rim didn't look straight enough then rather than filing the spoke hole I would look at another rim or even review my building technique.

4 of my bikes have got 36 spoke 4 cross lacing on the rear wheel and there is another 'spare' wheel the same, best pattern for strength/longevity.
Mind you the TT bike has a 24 spoke 2 cross/radial rear (Roval Classique Pave) and that seems plenty strong.
These

 

[dan_bo]

Bloody expensive way of life this if wheels just randomly give up the ghost! I wasn't off roading or anything!!

On road off road it doesn't really matter if the tension is a tad funny. Ive had (im a big lad) wheels run me around for three years and not had a peep then all of a sudden, after a retrue, ping a spoke or two cos they're not tensioned right. It happens to the best of em. Get em to chuck a new spoke in and see how it goes- if it carries on throwing spokes tell em to change it.