Serial Broken Spokes

[Steve O]

@vern 87324 wrote:

I know spokes break on occasion. But because I’ve broken two on the same side of the same wheel so close in time, I’m wondering if there are things I should be looking at/for in terms of prevention. All of my riding is on paved trail and roads. TIA.

My experience has been that once this starts happening you just have to replace the wheel. Either that or relace it entirely. You may want to carry a spare spoke with you in the meantime and hope it’s on the good side.

[Mikey]

I think Steve O is mostly correct. When the spoke breaks, the spokes on the other side get looser, and the adjacent spokes get tighter. When replacing the spoke and retruing the wheel, most of the spokes tend to get tightened again, sometimes overtightened. One thing you could do to lengthen the life of the wheel is to loosen every spoke after replacing the new one, then re-true. If the spokes seem too loose, then tighten each a quarter turn and true them again. If the spokes are too tight they will all start to go. If they are too loose, a couple will rub and break. Cary a couple to be safe just in case.

For me it’s always the cassette side.

[Harry Meatmotor]

It’s been my experience that, generally, multiple broken spokes are a sign that the wheel is under tensioned. Were the spokes breaking at the head or at the nipple?

When a loaded wheel rotates, each spoke is stretched and compressed, alternatively, as they pass from the bottom of the wheel to the top of the wheel. When there’s too little tension on the spokes, the spokes under compression will begin to fatigue, usually at the spoke head/j-bend.

From a materials perspective, what’s happening during most spoke failures at the head, is that the j-bend is elastically deforming every time the wheel makes a revolution. it’s not hard to imagine millions of cycles fatiguing all the spokes in a low-tension wheel, at about the same rate. therefore, when you see one or two spokes fail due to low tension, it’s really only a matter of time before you’re better off re-lacing the wheel.

also, depending on how long the wheel has been under tensioned, just adding more tension could fix the problem. However, if the spokes are breaking regularly and the wheel has more than a couple thousand miles on it, adding tension may cause the spokes to fail sooner.

Otherwise, I’ve definitely seen multiple spoke failures if the rear derailleur has either been rubbing the spokes, or allowed the chain to over shift in the largest cog, damaging the spokes.

[vern]

@Harry Meatmotor 87352 wrote:

It’s been my experience that, generally, multiple broken spokes are a sign that the wheel is under tensioned. Were the spokes breaking at the head or at the nipple?

When a loaded wheel rotates, each spoke is stretched and compressed, alternatively, as they pass from the bottom of the wheel to the top of the wheel. When there’s too little tension on the spokes, the spokes under compression will begin to fatigue, usually at the spoke head/j-bend.

From a materials perspective, what’s happening during most spoke failures at the head, is that the j-bend is elastically deforming every time the wheel makes a revolution. it’s not hard to imagine millions of cycles fatiguing all the spokes in a low-tension wheel, at about the same rate. therefore, when you see one or two spokes fail due to low tension, it’s really only a matter of time before you’re better off re-lacing the wheel.

also, depending on how long the wheel has been under tensioned, just adding more tension could fix the problem. However, if the spokes are breaking regularly and the wheel has more than a couple thousand miles on it, adding tension may cause the spokes to fail sooner.

Otherwise, I’ve definitely seen multiple spoke failures if the rear derailleur has either been rubbing the spokes, or allowed the chain to over shift in the largest cog, damaging the spokes.

Both broke at the head. Your comment and others all suggest it’s time to start over rather than the quick fix (replace spoke), which isn’t what I wanted to hear, but I reckon what I needed to hear.

As it regards the the wheel being under tensioned, I suppose then that the wheel could still be true even if under tensioned and therefore, my observation that the wheel was essentially true wasn’t enough, but that I also needed to test the tension of the spokes.

[Steve O]

I’ve never bought one of these, but I’ve always thought it would be handy to have–particularly with a cassette-side spoke break.

http://www.peterwhitecycles.com/fiberfix.asp

Any experience with these, anyone?

[Harry Meatmotor]

@vern 87375 wrote:

Both broke at the head… my observation that the wheel was essentially true wasn’t enough, but that I also needed to test the tension of the spokes.

Correct – the upside is that if the rim hub are still in good shape, it’s really not a hugely expensive proposition and many, many more miles could be had with your wheels. Or, this could be an opportunity to take a wheel building class.

Checking spoke tension is a little difficult without the proper measuring device (called a tensiometer). There are also differences in lacing pattern, spoke size and shape (i.e. bladed vs. butted vs. straight gauge), and rim and hub combinations that affect what an adequate tension for any given wheel should be.

[Harry Meatmotor]

@Steve O 87380 wrote:

I’ve never bought one of these, but I’ve always thought it would be handy to have–particularly with a casette-side spoke break.

http://www.peterwhitecycles.com/fiberfix.asp

Any experience with these, anyone?

They make sense if you’re going to riding a long way from home, or any other means of support, but in that case, I’d just tape 4 or 5 replacement spokes for both F & R wheels to your chainstay.

[cyclingfool]

@Steve O 87380 wrote:

I’ve never bought one of these, but I’ve always thought it would be handy to have–particularly with a cassette-side spoke break.

http://www.peterwhitecycles.com/fiberfix.asp

Any experience with these, anyone?

I had one for a while. I think it got nicked when my Surly was stolen (it was probably in the under-saddle tool bag). I tried using it once or twice, but I could never get adequate tension on it. I read and reread the instructions, though I have little doubt it was operator error.

The wheels I built for myself about a year ago have held up better than anything I ever bought pre-made (stock wheels, used wheels from Phoenix, and even new stuff from Handspun), so knock on wood, I won’t have any issues any time soon. That said, if I do go farther afield (e.g., an overnight on the C&O which is in the works or even more distant touring [sadly not in the works]), I’ll probably just do like Harry M. suggests and take a few extra actual spokes with me. I even have a mini cassette tool about the size of a half dollar to remove the cassette if necessary.

IOW, it’s a novel idea, and if used properly probably can help you out in a pinch. I’ve seen people speak glowingly of them online. Personally, though I wasn’t much impressed…

[jnva]

Just build a wheel like this and it’ll never break
http://youtu.be/sZ7dtrRrSTg

[hozn]

Yeah, agree with what others have said. Your wheel is likely under tensioned and tensions are uneven, so spokes will keep breaking. If you have an iphone you can try the spoke tension app. It apparently works quite well; you just have to measure carefully.

To ensure that the tensions are even you can just use tones too (but it helps to have a reference point). You probably want 120kgf on your rear drive side; I usually do around 110kgf on the front. Depends on the rims, but most support that. As you surmised the wheel being laterally true has rather little bearing on the quality of the build/wheel.

[Mikey]

I have much to learn, but need to build my own wheels. Okay, there goes the rest of my non-existent free time.

[Dirt]

Lots of good information here. Bicycle wheels are pretty amazing things. Well built ones are fantastically strong and remarkably light weight.

I’ve generally found that making sure that the wheel matches the rider helps a lot in the longevity of a wheel. The trend in wheels for the last decade or so is to have fewer spokes and a deep-dish rim. Wheels on less expensive bikes were made to look like the ones on high end bikes, but they may not function like their more expensive brethren. These wheels aren’t bad, but they don’t match all riders.

I’m a pretty big guy (6’4″, 200lbs) and I used to be quite a bit bigger (wider). I found that old-school wheels (32 or 36 spokes in a 3-cross lacing pattern (each spoke crosses 3 other spokes between the hub and the rim)) provided me the best ride and most durability in most conditions.

This might not be a bad discussion for a coffee club or happy hour. It is often easier to discuss these things with visuals and wheels you can touch and play with.

[mstone]

36 spokes 3x +1

I’m not a cute little person, I don’t need a cute little wheel.

[Harry Meatmotor]

to kind of tack-on to dirt’s comments: similarly to the old work triangle adage “Fast, Cheap, Good; Pick two,” for bike wheels it’s typically, “Light, Cheap, Strong; Pick two.”

[Dirt]

@Harry Meatmotor 87462 wrote:

to kind of tack-on to dirt’s comments: similarly to the old work triangle adage “Fast, Cheap, Good; Pick two,” for bike wheels it’s typically, “Light, Cheap, Strong; Pick two.”

Quite true. My inexpensive and strong wheels are definitely not light. You can mix those adjectives around in any combination and the statement tends to hold true.

[Author]

Posts