Vodalus

I'm a longtime cyclist but just started commuting about 6 weeks ago. About 5 weeks ago i switched out the tubular wheelset on my bike for some 36 spoke clinchers. Last saturday I went back to have my LBS make sure the wheels are still true.

I've put about 380 miles on the wheels since i bought them; 95 of those in the week since my LBS trued the wheels. Today on my way home i broke a spoke on the rear wheel. Thankfully i was only about a mile from home and was able to limp back.

I ride with a pannier strapped to my rear rack. it probably weighs in at 20-25 lbs most days. Could the extra weight have contributed to the spoke breaking after this little time? Or, could this have been some issue with the wheels themselves or with the way the wheels were trued by the LBS? I'd just like to figure out whatever I can to make sure it doesn't happen again in the future?

I think one of my mistakes is not knowing how to true wheels and replace spokes on my own. tomorrow that will change.

woodway

Where did the spoke break? Near the nipple or hub or in the middle?

No way your rack/pannier are causing a broken spoke on their own. I'd say the wheels already had a spoke issue or that the bike shop improperly trued the wheel. Ask around for a different shop that does a lot of wheel work and take it there and see if you get a better result.

FWIW, I weigh 185 lbs and commute with a rack/loaded pannier that probably adds another 15-20 lbs. to the total weight. I commute on 24 spoke wheels and have not broken a spoke in 17,000+ miles of commuting over the last three years. I am not particlarly gentle with the wheels either. I don't abuse them, but have no problem popping up or down a curb and ride over some crappy roads.

Vodalus

oops... forgot possibly the most important part. the spoke broke on the hub, the side opposite of the cassette.

Jonic

About a month ago, I noticed small cracks in my rear wheel where the spokes attach, about 10 total of varying severity. Figured I was headed toward a new wheel in the near future. About a week ago I broke two spokes (at the hub) on the ride home. The broken ones were on either side of the spoke with the worst cracks and that one was nearly pulled through the wheel. I knew the time had come for a new wheel. Put the new one one two days ago and noticed the spokes were no where near as taut as my old ones.

So now I'm thinking that my feeble attempt to true my wheels was probably behind the trouble but oddly every crack was on the cassette side of the hub. I did replace a broken spoke last year, also from the cassette side.

I'd be very interested in any thoughts/opinions that the collective knowledge base here can offer.

Other facts that may be pertinent, its a 10 year old Trek 7200 that sat largely idle for half that time. Only 4000 miles on the wheel with more than 25% of those this season and 3/4 of them from commuting the last 3 years. I tip the scales at 230 and the luggage adds another 10-20 pounds.

Cyclomania

Make sure when you replace the spoke that you cinch that puppy down;be sure you hear a high "ting" when plucking! A loose spoke is commonly the reason for spokes braking. Make sure that all of your spokes have that high "ting" noise! Rid your wheel of any buzzards. Or another way to find out the tension of the spokes is to take two spokes at a time and grasp them with index and thumb and press inward. If you come across a spoke that gives more than the others, tighten it! Spokes loosen over time and require tightening every now and then.

While truing spokes I'll commonly tighten the side that needs to be pulled one way or the other without loosening any spokes. Not usually a method recommended in bike books. My bad!

Mr. Spokesworth quote: "The high "ting" is the better ting to do!"

Jonic

I routinely was like a harpist, plucking away listening for perfect pitch from all the spokes. Its just that using that thumb/forefinger pinch technique on the new "factory-true" wheel, the tension is significantly less than that which I've been subjecting to my old spokes.

So is the theory of spokedom, tight and rigid or snug and flexible?

Cyclomania

Ahh Grasshopper, the theory is in the balance of the cyclist on the road to nirvana!

Sixty Fiver

Spokes require that they be tensioned within an acceptable range and most important is that the tension of each spoke is equal relative to the spokes on the same side of the wheel... cassette wheels are dished so the non drive spokes run at a slightly lower tension than the drive side spokes and a common mistake is for people to tighten these thinking they need to be as tight as the drive side spokes.

Non dished wheels like front wheels and rear wheels with internal gear hubs and single drives usually have no offset and the spoke tension on each side should be the same.

Even when those spokes are tight and rigid they are not static and need to withstand many thousands of stress cycles, a loose spoke will fatigue under repeated stress cycles and this can happen rather quickly.

A well made wheel will require very little attention, if any, over it's working life and if one is using rim brakes the rim should need to be replaced before the spokes need anything.

I build my commuting wheels like I do touring wheels as they have to withstand a lot of abuse and when you are depending on your bike to get you to and from work you want to know the wheels under you can take anything you throw at them.

If a rim develops cracks it needs to be replaced immediately as this is a sign of extreme failure that may be unrelated to the spokes and the build although in some case over tensioned spokes can pull a nipple through the rim.

DX-MAN

1. You do more miles than before, spokes MAY break sooner; they surely WON'T, though, if you're not riding.

2. It's a random thing; there's no way to really CSI this issue.

I'm tough on bikes and parts; big guy, pedal hard, like to bunnyhop rough stuff while I'm out, that sort of thing. I RARELY get more than 2-3 years out of a wheelset, no matter who made it. Also, I've had cheaper wheelsets give up spokes more quickly (but when I replace them, they NEVER break again, always a different one), as well as the issue of splitting rims. THAT doesn't seem to be a function of what I spent on the wheels, though......

Never expect things to just keep going; it's a bike, not an Energizer Bunny. Modern bikes are built with more inherent fragility, as they are made lighter for performance. Metal fatigues under stress, and less metal fatigues more quickly.

Cyclist01012

10 year old 7200. were the wheels by chance Bontrager Selects?

Sixty Fiver

I build wheels for big guys who carry big loads over long distances... 3 years tells me nothing of mileage and conditions and if you are running stock wheels the failure rate tends to be much higher than with hand built or better quality wheels.

I have wheels out there that have seen in excess of 10,000 km and have never needed a touch with a spoke wrench and my own wheels generally see a spoke wrench when it is time to replace a rim which is usually at 20,000 plus km.

My wife rides every day and is hard on wheels as she does not ride light and often tows a trailer... with weather factored in she has been getting 16,000 km out of her wheels that see a great deal of wet riding.

Sixty Fiver

Good point... some of these Bontrager wheels are dogs and if this is the case you may be able to get them warrantied.

Jonic

WOW Sixty Fiver! Reading your response and it all made sense. I am certain I over tightened all the spokes evenly, And thereby really overtightened the drive side. With the heft pounding relentlessly, no wonder the spokes were trying to pull through the rim. I guess I'll either learn the proper tensioning or leave it to the truing professionals.

DX-MAN I totally get that nothing lasts forever, add in my lack of basic maintenance to this bike and its a wonder I went as long as I did without serious failures.

Milice I just looked at the old wheel and the only label is on the shimano hub. I think Trek hadn't started the conversion to Bontrager when I bought the bike as the rack and trunk I bought then have the Trek labels. But it wasn't long until everything went Bontrager.

Thanks to all for the tips and insights.

rumrunn6

spokes break. but you might have a different shop do your spokes. watching a pro do it is a wonderful thing

Drew Eckhardt 

Spokes don't break in properly built wheels for the first few hundred thousand miles unless you shift the chain into them or something similar. Merely crashing and bending a rim usually doesn't hurt them.

You bought shoddy wheels.

You might have gotten lucky and broken the one spoke with a manufacturing defect, although you probably just discovered that the wheels

1) Weren't stress relieved. Expect the other drive side spokes to fail until you've replaced them all (they all have about the same residual stress from the elbow forming operation and see the same fatigue cycles at 750/mile).

2) Weren't tensioned enough. If not corrected you can expect the non-drive side spokes to fail individually as they flex back and forth like a paperclip you've decided to break.


It contributed. The number of fatigue cycles survived are a function of average stress and the amount of variation. Average stress issues mostly come from parts of the elbow which were never taken pat their elastic limit and therefore have parts with high residual stress from the forming operation. Variation comes from the amount of weight you + bike + luggage put on the wheel as the bottom spokes unload with each revolution.

The root cause was other construction defects.

Learn to build wheels and make a set around nice serviceable hubs (Shimano Ultegra would be a fine choice for road hubs since you can get loose bearings, cones, and replacement freehubs) with commonly available rims and DT Competition 2.0/1.8 spokes. When you wear out the brake surfaces on a rim or bend it in a crash de-tension the wheel, tape the replacement next to the existing rim, move spokes over one at a time, and then tension like building a wheel from scratch except you won't need to stress-relieve. The spokes should be fine for the first few hundred thousand miles unless you get something hard like a chain stuck in them.

You want to read _The Biycle Wheel_.

fietsbob

Budget wheels may be built with spokes made of wire with some impurities,
several spokes have been known to break due to flaws in the metal, used.

Superior : hand built wheels, using top quality spokes .

rhm

+1 to what he said.

If your spokes are breaking, it's because they weren't tensioned right. 350 miles is enough to fatigue poorly tensioned spokes (I know this from personal experience) and now they are all destined to brea (and I know this from personal experience, too). Have them all replaced, have them tensioned right, and they will hold up just fine.

Doohickie

This is it. I think the design weight for a lot of wheels is about 200 lb. A little over that and you're okay for a while but it will catch up to you.

Just get a new wheel and be done with it. I bought a new, modestly priced (< $120 for both wheels), wheel set for my commuter after I started popping spokes on the original wheel. Solid as a rock. My sense is that unless you get a high-end bike with handbuilt wheels, factory wheels will work good for a 200+ lb. rider for a time, then the spokes start to break. When you break the first one, it over stresses those around it, contributing to the next break in a kind of domino effect. You can either replace all the spokes or get a whole new wheel.

I took care of the commuter hybrid a while ago. Recently spokes started breaking on my single speed and I will soon be building a new wheel for that.

As for the contribution of commuting? The weight you carry might be a small factor, but I think the bigger factor is that if you commute the same route repeatedly, you probably know where the hills are and after a while you attack them more systematically. Whenever I've popped spokes it's been during a climb. Also, hammering away when the light turns green to position yourself in traffic can put a fair amount of stress on the spokes. It's not really that you weigh 230 that's the problem, it's that a 230 lb. rider will put more power through the drivetrain than a 150 lb. rider for the same acceleration.

Drew Eckhardt 

Either you haven't ridden much or you got lucky.

The stress hardly changes. The spokes fail about the same time because its dependent on fatigue cycles and they've all seen the same number (at 750 a mile as they rotate past the bottom of the wheel and unload), magnitude of the variation, and about the same average stress (with residuals from the elbow forming operation being the big problem).

If you get your cheap factory wheels to high uniform tension and stress relieve them before putting any miles on them you'll probably be fine.

dynodonn 

I've had good luck with my current set of wheel which have better quality spokes than the factory versions, also going to a lower pressure tire also may have helped as well. I've carried some heavy cargo loads since the addition of the new wheel set, and no spoke breakage has occurred so far.

John_1961

I have the same problem seems I brake a spoke at least once every year OY Not fun during a commute

Praxis

Obviously just my experience, but the only time I've ever broken a spoke it was from my wife accidentally knocking over the bike in a wheelbender rack in the garage. I'm 170 lbs, 36 spoke wheels, rough roads/riding.