jimmuller 

Two broken-spoke events. Well, three actually.

About 2/3rds of my commute home one afternoon starting up a moderate hill on the Masi I heard a pop, a rear wheel drive-side trailing spoke. But it wasn't the spoke, it was the nipple. First guess would be a spoke too short, but a second glance showed the spoke protruding 2mm out of the nipple's shaft still on the spoke, the head apparently having stripped its threads. I'd built that wheel but in fact the spokes, sized for me by the same experienced LBS guy who'd was also selling me the rims, had seemed short at the time. I took on faith that the LBS guy got them right, should have been more skeptical. I restrung the entire wheel with new spokes.

Had a drive-side spoke pop on the tandem when we hit a bump on an uphill. I believe I think I remember that it was a leading spoke. Of course it was head-out so restringing it was a pain. Some months later another one popped and that's when I noticed the crack in the rim. Decommissioned that rim, built that hub into a new rim with new spokes. It had not been strung "correctly" anyway.

FBinNY 

Feel free to test, but it's been done often enough. In fact the OP has just tested and reported on it, though that wasn't his intent. It's not only a question of a static test, but fatigue cycles. If you look at the photo on the left, you'll see that the thinnest section lines up with the rim. That means that you have a stress riser at the fulcrum, which is never a good thing.

And, yes there is the danger of over running the top of the nipple. On single wall rims, it means having to grind the spokes. This was very common practice BITD, and a number of tools were made for that job. Then someone got the bright idea that erring low (in some cases very low) would save money, and good practice gave way to convenient practice.

The other issue with erring long is hat you out of thread. This is the important issue for those of building with double wall rims. So, don't aim for the top of the nipple, aim for the slot. That gives you a margin of error of about 1mm in either direction. Or if building double wall rims, shop for spokes and nipple combinations that allow overrun of 2-3mm. Then you can aim high and still have margin for error.

jimmuller 

But don't put blind faith in the database of dimensions. (I've seen errors.) Measure the rim's ERD on a bunch of different diameters. There are several ways to measure it, so try as many ways as you can think of. And don't forget that the real ERD for the spoke length has to include 2mm extra radius for the nipple. Which is to say it shouldn't be called ERD, it should be Effective Spoke Head Diameter.

FBinNY 

Just to set the record straight, I'm one of the least fastidious people about wheels or anything bike related. I consider bikes to be a means, not an end, and my bikes see rough service and very little attention. Months can go by without me touching them, and save for some basic attention when I set them up, I expect parts to last until they break or wear out eventually.

I've ridden through all kinds of weather, through floods, off the ends of piers into lakes, ride a light road bike off road, and just about every "sin" folks describe here on BF.

But I've been around a long time, and remember when bikes were built properly by people who didn't believe in doing it twice.

When it comes to wheels, it's very easy to build a wheel, that will not break a spoke EVER, and will last until crashed or the rim wears out. This is proven time and again here on BF, and if the thread asked about how far people have ridden without a spoke failure, we'd get dozens of posts with figures upward of 25,000 miles or so.

55murray

I broke a spoke on my coaster brake cruiser this past fall, like the OP I noticed a faint ticking once per rotation and after a couple days discovered the problem and noticed the slight wobble as well. Rear wheel, old fashioned bolted down set-up: Once I get my old coaster brake bikes set (aligned, bearing pressure and chain tension perfect) I hate to ruin it all with a removal but oh well, gotta get to that spoke...

Due for new tires so I'll do that while it is off, front as well. Have to remove the cog to thread the new spoke, might as well overhaul and repack the hub if I'm going that far. Cog showed bent teeth, order a new cog and install that too. At least the chain was still good.

By some miracle I also remembered to replace the one spoke.

dufeau

I was riding home from (?the pub) somewhere, and I noticed that my rear wheel was rubbing the chainstay. I thought maybe I hadn't tightened the QR, and it wiggled loose, or maybe the wheel was a bit out of true. Stopped to inspect and saw this on my campy nuovo record hub: the spoke hadn't failed, the hub had

I bought new hubs but still haven't laced them (wheel building is scary)

Instead I bought a wheelset--my first tubulars!

Why is posting images here so difficult?
https://goo.gl/photos/jw1oM4myDzth4wWw5
https://goo.gl/photos/HQFSD1DRwU3h62B6A

obrentharris 

My most memorable broken spoke incident was on a mountain bike in 1984. I had never before ridden a mountain bike, so when a friend came over with his bike and a Ritchey that he had borrowed from a friend for me to try I was eager to sample this new way of bicycling.

We climbed the fire road to the top of the forested ridge near my home and rode a fine 10 miles or so along the ridge. I was having a blast! When we decided we should find a route to drop back into the valley neither of us knew the area well, but we found another fire road that descended steeply in about the correct direction.

The steep fire road turned into an even steeper single-track trail. The single track trail disappeared into an even steeper grassy slope. We could see another fire road at the bottom of the 1/4-mile-long slope so we decided to go for it. It really seemed to me at this point that you could go anywhere on a mountain bike. Part way down the slope my front wheel dropped into a hole hidden in the tall grass and all forward momentum stopped... well, all forward momentum stopped except me catapulting over the handlebars and landing foot first into the front wheel breaking a spoke! I've been hooked on mountain biking ever since.
Brent

jimmuller 

He! Not half as scary as having a hub break.

(Actually, it's easy.)

okane

Riding the local rail trail during hunting season and heard a sharp "zing" sound that sounded just like a bullet passing close by (ricochet off the frame?). I had heard a similar sound when in the pits marking targets during shooting matches.

First instinct was to hit the dirt, so i laid the bike over and kissed the ground not knowing if more bullets were coming.

Laid low for a couple of minutes before getting up and examined my bike to see if it had suffered any damage,

The laugh was on me because I saw a broken spoke that obviously caused the "zing". Fortunately no one was around to question my sanity, but it did sound like a bullet, honest!

SJX426 

Yup. If this spoke was near the same tension of the others measured, it was about 17 clicks on the Park tension meter. According to the chart, 70 kgf for a 1.8 steel spoke.

[IMG]Failed Nipple, on Flickr[/IMG]

USAZorro

Many years ago, the rear wheel of my second wheel build had been riding nicely for a month or so when a NDS spoke broke. I replaced it. The next ride, two more NDS spokes broke. hmmm... bad batch of spokes? Nope. Novice wheel-builder error. Had routed spokes to holes on the opposite side of the rim (which had offset spoke hole drilling).

The wheel was fine after I rebuilt it.

Salamandrine 

I have not broken a spoke in years. BITD when I was riding 15k a year, I broke them fairly often, typically as a rim was reaching the end of its service life, but sometimes randomly. To me this seems like a silly question, like how many flat tires have you had?

I suspect DT has improved their metallurgy in the last 35 years.

The idea that a properly built wheel will not break spokes is ridiculous. In fact the entire ego driven 'properly' built wheel concept is ridiculous -- but that's a different subject. Given all that, I find that spending a bit more for double butted spokes pays off, as they are very much less likely to break.

Repack Rider

The carbon fiber bike came with 28 blade spokes on the rear wheel. I broke them way too often. Went to Steve Gravenites, probably the only wheel builder with name recognition ("Gravy Wheels") and told him I wanted a 36 spoke, 14-gauge rear wheel. Found an old Campy hub for him to build it on, and he used a tandem rim.

Problem solved.

Robofunc

I was about 15 miles from home on the local rail trail when I heard a startlingly loud ping. The rear wheel felt instantly wobbly and started hitting the brake. It was still rubbing badly even after opening all the way. Had to call for a ride.

Turned out it was a rear drive-side spoke that had snapped near the middle. The wheels were built around 1989/90 using stainless spokes. Apparently there was a rash of bad stainless spokes at that time that are prone to some kind of carbon embrittlement that manifests as black spots on the spokes. Those spots actually eat into the metal and weaken the spoke—a serious bummer as these wheels have lasted a long time. They've been hanging up ever since just because I don't really trust them.



The whole experience wouldn't have been so bad if weren't for the owner of a local shop about a mile away. I clomped there in my cleats only to have him grouchily tell me he was too busy to help me (while chatting casually with a friend, not working on anything and no customer bikes anywhere to be seen) and refuse to let me borrow a spoke wrench, even after I offered to pay him for his "troubles." To this day I tell people to steer clear of that place.

jack002

I had a huffy banana seat bike, I carried a lock for it, just a cheap master lock, I hung it on the right seat stay by the hub (bad). I lost the key to it and it was stuck there. When I'd hit a bump up it'd come and knock out a spoke. I tried to tape the lock down and suffered many broken spokes to it. Got someone to cut it off with a bolt cutter a few years later. Bought and replaced many spokes on that wheel.

JReade

I had a nice wheelset that I got with a bike, I liked riding it. I'm not a small man - 6 foot 5, 210 pounds, but I try to ride really light on the bike. I had a spoke break on the rear. The same way yours did. Off to the co-op and replace the spoke and true the wheel. Great. Two weeks later, same thing. This time, I'm talking to one of the guys in the shop as I'm doing it, and he relays me the same story. "Two spokes broke in the MIDDLE? They are all trash. You're gonna keep breaking spokes now, and eventually you'll have a freshly re built wheel, but 1 spoke every two weeks. " Stripped them down and sold the hubs.

Robofunc

Yeah, those spokes are all suspect now. I really like the wheels, though (105 hubs, Ambrosio rims), so I'll probably end up re-building them eventually.