eduskator

I was climbing a steep hill (good amount of stress on the drive-train) when I heard a loud noise in the rear. I initially thought my chain had skipped a gear on the cassette, but I didn't feel anything so I knew it was something else. After a few more kms, I looked at my rear wheel and saw it was misaligned so I stopped and saw that a spoke was missing on the non-drive side. I turned around & went looking, but didn't find it. I guess it flew away when it snapped. A part of the spoke went inside the rim though and is stuck in there. The good news is that it didn't get stuck in the drive-train and didn't mess my derailleur.

I know this stuff happens, but I really thought these wheels were bulletproof (Giant SLR1, 32mm). I mean, it's not like I stepped in a pothole or anything so the spoke must have been either previously weakened due to a hit or at a different tension (looser?) than the rest. My bike is 1 year old and has roughly 5000kms on it. I ride in areas where pavement is in good condition and it's not used to commute at all. I am a little disappointed by the fact that a spoke snapped after such usage, but I am not sure if I should be or not.

Are there wheel gurus out here that could help me understanding what happened? I would be interesting into getting a few opinions since I don't know much about wheels.

jnesss

bring it back to giant. my gravel bike's hub starting making a ticking noise. the tech at giant said it was fine. I wouldn't take no for an answer, left with a replaced rim / hub.

upthywazzoo 

Spokes break, that could happen on any wheel due to fatigue. A well-built wheel distributes fatigue evenly and has a better lifespan than a poorly built one. Do you have a pic of the remaining spoke?

eduskator

That's what I thought, at least until yesterday! Giant's DBL technology is supposed to improve the wheel & spoke strength & durability.

For the broken spoke, unfortunately no! It flew off when it snapped, but I'll have a better idea on where it snapped when I'll remove the remaining part that's stuck between the rim & tape. I have a feeling it broke where it tightens inside the rim.

WhyFi

It happens. Also, aren't you a bigger guy, at least in compared to wispy roadies? Stuff gets stressed.

Take the wheel to the shop, have them look at it. I would assume that it's got at least a two year warranty, if not lifetime. Just an FYI, though, when I popped a spoke on my Reynold's last year, for it to be covered under warranty, they wanted to rebuild it, not just replace the spoke and double-check tension. IOW, I had to be without it for about a week (two way shipping plus time in the shop).

Koyote

If the bike is under a year old, it should be under warranty. If not, it's still not very expensive to have a spoke replaced...But then be sure to have ALL of the spokes checked for proper tension.

Something similar happened to me once on an almost-new bike. (it had about 2000 miles). Manufacturer replaced the spoke and checked everything else out, and it's been fine for another 20,000 miles or so.

eduskator

Thanks for the tip. I'm heading there shortly. It would make sense to having to rebuild it completely. Will talk with the manager to see what can be done. I am close to 185 lbs right now. A little heavier than the average joe, but at this time of year, I lost most of the accumulated holiday season belly fat though

WhyFi

Yeah, I'm about the same size. Stuff gets torqued. If they just replace the spoke, I wouldn't be too concerned about it if they re-check the tension all of the others, but a rebuild would be more desirable.

eduskator

Super. I'll go with the least expensive option as long as it's reliable. Anyhow, the Pro 0 2021 is already on my mind and my 30th birthday is coming soon

Drew Eckhardt 

Metals fail due to fatigue, with the cycles survived a function of average stress and variation.

In machine built wheels, parts of the elbows have high average stress because they were never taken past their elastic limit.

Spokes unload passing the bottom of the wheel about 750 times a mile, with stress cycle magnitude dependent on rider weight. Rear spokes also see tension variation twice per crank rotation from sinusoidal variation in pedaling force normal to the crank arms.

With each spoke slightly different the failures are spread out in time like popcorn kernels opening - one, a few, most of them, a few, and any remaining stragglers.

With heavy riders this can start in a few thousand miles.

Conversely, when you take the time to properly correct spoke lines and stress relieve wheels the spokes can last 300,000 miles or more.

If you're lucky you had one defective spoke. Otherwise you've used up most of their fatigue life, and will have problems until the spokes are replaced in the failing half of the wheel (drive side or non drive side).

eduskator

Good explanation, makes sense. I hope it was only a defect. Covered not under warranty, I will be a happy camper if the fix solves the problem permanently.

popeye

If another spoke breaks it's time for rebuild/replace. This is not uncommon for machine built house brands one year old.

eduskator

Yep, I'll cross my fingers. I just don't like losing my bike for a week or so, especially not at this time of year. It normally takes no longer than a day to repair a spoke, but all shops around my place are busy as hell due to the current situation.

Makes me regret not having bought a commuter/gravel bike last winter when I had the chance to. 2 bikes is better than 1, that's for sure!

popeye

If you can get them to sell you a spoke you can do this. Replacing just one spoke is not a big deal and you and have it tuned later if necessary.

eduskator

I know, pretty easy to tight it to the proper specs by just making sure the rim gets straight again, but since I needed to go to the LBS to get a spoke, I left it there & asked to check all of them while they're there. It'll save me the hassle of having to sit the TL tire again on this non cooperative rim. This combination of TL tire & rim is not user friendly at all.

Aladin

Always this parrot internet route.. comic. Sometimes.. yes. But more often than not the 1st replacement was done haphazardly.. still need to get said wheel ROUND again w balanced tension. Shops want the 20-25 bucks for 15 minutes and the buck spoke.. that route means more breakage.

OP did not state what rear lacing was... Giant is like all other them.. more on promises than results.

And.. new computer built wheels are hard to beat when examined closely. Yet the machine produces the tolerances programed... at times lacking the original goals.

popeye

I can't say I agree with anything you have posted. The most important step in building a strong wheel is detensioning which happens with almost all hand built wheels but never with machine. Nice snarc tho. If you have a wheel that breaks 2 or more spokes it is junk, fact not opinion.

Dan333SP

A far cheaper way to not be without your bike while getting the wheel fixed is to just have a cheap pair of backup wheels. Hell, the shop may even have a wheel they can loan you while they repair the broken one.

Fox Farm

Spokes will break, regardless. My carbon wheels have the standard J hook spokes. A year ago, on the two year old wheels I had a rear spoke break while I was out of the saddle climbing. It was a very inexpensive repair. I am surprised that you actually lost the entire spoke! There should have been part of it at the threaded nipple. It likely broke at the J bend.

eduskator

Even better, I am buying a second bike. It was already planned to get a commuter bike. It's hard to find parts or bikes right now though with the current COVID context. LBS are out of everything.

There is a part left inside which might be reusable. Still waiting for the LBS to call me back to see what had to be changed. I kept on riding when it happened because I didn't see anything or heard anything rattling after hearing the snapping sound. Perhaps the spoke was hanging loose & flew away after a few hundred meters. I'll never know.

Aladin

Sound plan.. least ways a back up rear.

J bend breakage.. usually the inbound spoke.. elbows have zero flange support. Using butted spokes w washers to tighten that gap significant improvement in durability.

But yes.. spokes do break. Thing is.. get the replacement done by someone who knows the game.

This one I'll toss out... the keyboard queens will spend the afternoon on it. All RADIAL spokes rear.. laced outbound. Flange contact/support. The booook reading queens will whine NO torque..

WhyFi

Wait - you're recommending that he lace the rear radially?

Aladin

12-8.. all rad-I-AL. Stiff.... all the spokes SHARE the same load as same time. Otta give the keyboard queens something to do.

WhyFi

A radially laced, disc brake, rear wheel. Sure - what could possibly go wrong?

upthywazzoo 

Theorycrafted for a bit.

A) The forces on the rim during braking would be the same, regardless of lacing pattern (I think)
B) As the wheel continues rotating forward (resisting the deceleration at the disc rotor) a J-bend spoke would rotate slightly in the hub flange, causing more serious wear on the flange holes.
C) B) works in reverse, as well. During accelerations, the hub will spin up before the rim and there will be some rotation at the J-bend. Maybe a huge spoke tension could fix this though.
D) If the hub flange were beefy enough, radial disc could be doable? Could someone invent a radial straight pull hub that would be able to handle this better?