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-   -   3 broken spokes in 8 days (http://www.bikeforums.net/bicycle-mechanics/930579-3-broken-spokes-8-days.html)

Buzzatronic 01-19-14 11:55 PM

3 broken spokes in 8 days
 
I have a over 5,500 miles on my current bike since Feb '13 and in the last 8 days I've popped 3 rear spokes on my commutes and group rides. Before this I've broken only 1 other rear spoke (back in August I think) and that was when I hit a big bump with a very heavy load in my panniers and I heard it pop.

I've had them all replaced by the LBS and on the most recent trip the guy mentioned that it looks like my rim took a big hit at some point and has a slight divot in it (making it not perfectly round) and that overall, my spokes seemed to be low tensioned. I had him replace the spoke, true the wheel and re-tension all the spokes (and true it again). Today after my group ride, I check my bike and sure enough, another spoke is broken. :(

Is it time to cut bait with this rim and rebuild the wheel or replace the whole thing?

TallRider 01-20-14 12:02 AM

It is probably time to cut bait with this rim and either replace the wheel, or rebuild with new spokes and probably new rim (assuming the flat spot is bad enough).

Over time, spokes can fatigue at the elbows (where they enter the hub). This happens if spoke tension is too low, and so tends to happen mainly on the non-drive-side of the rear wheel. Tension in a given spoke will change somewhat as the wheel rolls around, and if spokes are low-tension enough (combined with loads), spokes can go slack and then re-tension each time the wheel rolls around. This leads to repeated flexing of the spoke at the elbow, and eventually it snaps.

Once you have multiple spokes breaking in succession, it means that most of the other spokes are fatigued and at risk of breaking also. Again, I'm mainly talking about non-drive-side spokes breaking at the elbow.

Buzzatronic 01-20-14 12:34 AM

Quote:

Originally Posted by TallRider (Post 16425087)
Again, I'm mainly talking about non-drive-side spokes breaking at the elbow.

Yes this seems to be where they are breaking. :(

So it sounds like my options are
1) Keep the rear hub and replace the rim and all the spokes or
2) Buy a brand new rear disc wheel

Either way I'm probably gonna have to drop $100-200 on this yes?

TallRider 01-20-14 01:13 AM

with option (1) you could probably get away with keeping the drive-side spokes (since they are higher-tension, they rarely start breaking at the elbow because of fatigue)
with (2) why are you talking about a disc wheel? Is there a reason you'd prefer that over a regular spoked wheel? disc wheels are usually only for rear wheels on time trial bikes, and they don't handle well in wind.

$100-200 sounds about right for a new wheel. And new rim+spokes+wheelbuild will probably run you in the same range.

rpenmanparker 01-20-14 05:37 AM

Quote:

Originally Posted by TallRider (Post 16425164)
with option (1) you could probably get away with keeping the drive-side spokes (since they are higher-tension, they rarely start breaking at the elbow because of fatigue)
with (2) why are you talking about a disc wheel? Is there a reason you'd prefer that over a regular spoked wheel? disc wheels are usually only for rear wheels on time trial bikes, and they don't handle well in wind.

$100-200 sounds about right for a new wheel. And new rim+spokes+wheelbuild will probably run you in the same range.

Perhaps OP means disk BRAKE wheel.

loimpact 01-20-14 08:01 AM

I'm just curious on which bike of yours is this??

And are you committed to the exact same wheel you already have??

I often see wheels on CL and what not for pretty cheap. Unless you're married to a matching wheel or upper brand, I'd certainly think you could manage under $100, no??

cycle_maven 01-20-14 09:58 AM

Yep, the low tension from the first wheelbuild was the culprit. All the current spokes are now weak, and will pop like popcorn in very short order. Time for a new wheel, or at least a new spokes properly tensioned and stress-relieved. If the rim is whack, then a new wheel unless you really love your hub for some reason.

digibud 01-20-14 11:34 AM

I would detension all the spokes completely. If the wheel was still nice and true I would find a different wheel builder and the wheel rebuilt. It wouldn't surprise me to find the wheel was not true when untensioned then I'd do the water test. What's the water test, you ask? It's where you toss it in a bathtub and see if it floats. Doesn't float? Throw it away. I weighed 250lb when I got my current set of wheels that are 20/24 and although I've lost some weight since, I've about 10,000mi on them with only a very minor truing once or twice. If I even broke one spoke I'd do the above procedure. Breaking as many spokes as you have would leave me leery of my wheel entirely collapsing on me on an unseen downhill pothole.

Buzzatronic 01-20-14 12:05 PM

Quote:

Originally Posted by rpenmanparker (Post 16425280)
Perhaps OP means disk BRAKE wheel.

Yes sorry, I meant disc brakes. :)

Buzzatronic 01-20-14 12:06 PM

Quote:

Originally Posted by loimpact (Post 16425453)
I'm just curious on which bike of yours is this??

The 2012 Jamis Bosanova.

Quote:

And are you committed to the exact same wheel you already have??
Nope, just something that'll support my current disc brake system, 10 speed Tiagra cassette and the load of a rear rack, trunk bag and panniers.

Buzzatronic 01-20-14 12:07 PM

Quote:

Originally Posted by digibud (Post 16425981)
If I even broke one spoke I'd do the above procedure. Breaking as many spokes as you have would leave me leery of my wheel entirely collapsing on me on an unseen downhill pothole.

Yes that's what I'm worried about for sure. Rode the backup bike to work today because of it. :(

Bill Kapaun 01-20-14 12:08 PM

How big is your "divot"?
Often, a rim will have a slight flat spot at the joint, opposite of the valve.
What brand rim/wheel/hub? How many spokes?

digibud 01-20-14 12:18 PM

Quote:

Originally Posted by Bill Kapaun (Post 16426089)
Often, a rim will have a slight flat spot at the joint, opposite of the valve.

Really? I'd accept about 1mm of off-true. Beyond that I'd look for a better wheel.

Buzzatronic 01-20-14 12:40 PM

Quote:

Originally Posted by Bill Kapaun (Post 16426089)
How big is your "divot"?

It's pretty small, hard to see unless you're looking for it and nothing I can feel while riding (until a spoke lets go, then I get the wobble)

Quote:

What brand rim/wheel/hub? How many spokes?
It's the stock wheel that came on the Jamis. Formula disc hub, 14g steel spokes, Alex DC25 32H rim.

Jeff Wills 01-20-14 06:53 PM

Quote:

Originally Posted by cycle_maven (Post 16425724)
Yep, the low tension from the first wheelbuild was the culprit. All the current spokes are now weak, and will pop like popcorn in very short order. Time for a new wheel, or at least a new spokes properly tensioned and stress-relieved. If the rim is whack, then a new wheel unless you really love your hub for some reason.

Ditto here. My rule of thumb is: one broken spoke could be a fluke, two broken spokes is a trend, three broken spokes makes it certain. By now, all of the spokes are fatigued. Even if you were to have it professionally trued and tensioned, you'll continue to break spokes.

FWIW: Universal Cycles has a couple wheelsets on special right now. If the dealer doesn't cover them under warranty, you might consider them: http://www.universalcycles.com/shopp...s.php?id=65581

Buzzatronic 01-22-14 03:47 PM

Quick update on this: Looks like Jamis is going to replace the wheel under warranty.

Thanks for all the replies and advice. Hopefully this wheel holds up a bit better. :)

TallRider 01-22-14 04:04 PM

nice that you're able to get the wheel replaced under warranty.
I would recommend that you get the replacement wheel trued/tensioned by someone who is good at these things (likely working at a shop). That will make it more likely that you get long useful service out of it, without more broken spokes.

I overhauled my Dad's bike while visiting my parents over Christmas, and was proud that both of his wheels are within 0.5mm of perfectly true, after I trued/tensioned the OEM wheels 7 years ago. My dad weighs 200 lb.

Buzzatronic 02-26-14 01:59 PM

Closing the loop on this. I finally got my bike back after a month. The replacement wheel from Jamis finally made its way to the LBS and they installed it yesterday. Added bonus was Jamis sent a full wheel set replacement so the LBS replaced my front wheel too. Mechanic at LBS confirmed all the spoke tensions on the new wheels as well so I should be good to go. Gonna ride it on Friday to test everything out.

nymtber 02-26-14 03:21 PM

Awesome to see Jamis warranty the wheels!

Now, if the LBS had checked tension before selling it, this problem may have never come up...

Hope you can now rack up some trouble-free miles!


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