When do I cut my losses on broken spokes?
June 28, 2012 9:57 AM   Subscribe

I keep breaking spokes on my rear wheel! My bike is only a few years old (more than 2, less than 5), and I've broken 3 spokes so far this season. Help!

Last summer I discovered a nice section of unpaved trail that linked two normal paved trails so I started riding it as a change of pace. However, at the end of the year my rear wheel was pretty far out of true. It's a hardtail bike, so it's not too surprising. The local wrench expressed doubt that he would be able to get it true and round, and to my surprise, he did. (mostly. Within reason, anyway. It's more true than round, but not enough to be uncomfortable.)

But this summer, I'm going through a spoke a month. They're all breaking at the head, two on the freewheel side, the latest one on the left side. I don't have a spoke tension gauge, so I can't tell if the spokes are just pulled too tight to bring the wheel in to true. They don't feel too asymmetric when I manually squeeze the spokes to let them reseat (ping! ping! plink!) after getting the wheel back from the shop, though. The two on the drivetrain side broke under torque, but this most recent one just went ping as I crossed the road.

When do I cut my losses and just buy a new rim and have it built up? Or is the rim probably alright (assuming they're checking the spoke tension, I'll ask) since it can be pulled into true, and I'm just experimentally discovering the wear life of my spokes? Having the rim rebuilt with all new spokes instead of onesy-twosy spoke replacement at ~$18/pop seems like it would be cheaper, but it might be a case of diminishing returns.

The bike is a relatively cheap clunker of a Trek hybrid, so the wheels aren't particularly exotic. Anything but! But since the bike is cheap, I hesitate to spend a couple hundred on a new wheel (labor and local price, estimating) when I could buy a new shiny for a few hundred more.

I checked Sheldon Brown, and I couldn't find any guidance there. Do I just keep replacing spokes as they break, replace all the spokes (keeping my hub and rim), buy a new rim, or buy a new wheel? I think I'm already behind the curve for buying a truing stand and a box of spokes, but I never was all that good at truing wheels myself, which is why I let someone more experienced than myself handle it.
posted by Kyol to Health & Fitness (18 answers total) 1 user marked this as a favorite
It's time for a new wheel.
Your rim *might* be okay, but you certainly need it all re-built. When you break one spoke, the others take up the tension and the ideal, even distribution of tension gets wonky... when you keep breaking spokes it's a sign that the whole system is out of wack.

Best bet is to have your local bike shop sell you a basic rear wheel. It'll probably be cheaper than buying new spokes (a buck a pop), and a wheelbuild (usually 35-50 bucks).
posted by entropone at 10:05 AM on June 28, 2012

Just buy a new rear wheel, you can get a fairly reasonable one for $100 or so. There is no point in a rebuild if the hub is cheap anyways, and you don't want to reuse the rim.
posted by ssg at 10:09 AM on June 28, 2012

What others said, also: If the problem is spoke tension, then, based on all the discussions I've had about bike wheels (and with the caveat that I let other people do my wheel building), it's likely that your issue is that they're too loose, not too tight. Loose lets them flex and that eventually weakens them. If you actually get into tension measurement and measuring your spoke tension, it's likely that you'll find that your spokes all need to be tightened way up.
posted by straw at 10:13 AM on June 28, 2012

They don't feel too asymmetric when I manually squeeze the spokes to let them reseat (ping! ping! plink!) after getting the wheel back from the shop, though.

Your lbs isn't finishing the job if the wheel is plinking after you get it back. They aren't properly stress-relieving. Those noises are the spokes reseating and perhaps even detorcing following tensioning. In the best case, a mechanic should continue to tension and true the wheel, followed by stress-relief until the plinking sound stop. At that point, the wheel is strong and true.

You can finish the job yourself with only a spoke-wrench and your front fork as a truing stand. Follow Brown's procedure, working around the wheel pulling on the spokes in groups of four, then retruing. A simply way to assess true is taping a sharpie forks (I used to use the brake pads) and then rotating the wheel. Black lines where the tip of the sharpie contacts the rim indicate a wow in the rim and thus the place where the spokes need more tension. Do no more than a quarter turn a time, an eighth (or less) as you get toward the end of the process.
posted by bonehead at 10:31 AM on June 28, 2012

I had a similar problem last year-- a new wheels not only solved it, but my ride is 50% better to boot. One wheel was about the same price as getting 4 spokes replaced intermittently and a hell of a lot more convenient.
posted by activitystory at 10:32 AM on June 28, 2012

A new wheel is cheaper than a coccyx x-ray. Get a new one (wheel, that is). Replacing a wheel is an easy operation; substantially easier than building a wheel. It's only slightly more involved than fixing a flat tire.
posted by chairface at 10:34 AM on June 28, 2012

Loose lets them flex and that eventually weakens them. If you actually get into tension measurement and measuring your spoke tension, it's likely that you'll find that your spokes all need to be tightened way up.

This is quite inaccurate. Spoke flex is what gives wheels their strength. Things that don't flex break.

How much tension is based on the type of rider, the intended use of wheel, the gauge of the spokes, the pattern of the lacing, and other variables. Sometimes, too little tension is a problem. Sometimes, too much tension is a problem. I don't think there's enough information to recommend that the OP tighten their spokes way up.
posted by entropone at 10:40 AM on June 28, 2012

Best answer: I don't know if this is at all relevant, but I had a similar problem with spokes breaking recently. Talking to a couple bike mechanics, we came to the conclusion that the fact that I'm a fairly big guy, plus that I often carry stuff in paniers, plus that the bike wasn't terribly expensive to begin with meant that the rear wheel my bike shipped with just wasn't up to the strain I was putting on it. A new wheel (~$130) has fixed the problem so far.
posted by no regrets, coyote at 10:42 AM on June 28, 2012

Asymmetric tensioning does cause differential loading on the spokes and thus failure. "Plinking" and the failures all happening at the spoke head are symptomatic of this.
posted by bonehead at 10:48 AM on June 28, 2012

You may have a wheel built with cheap chrome- or zinc-plated weak steel spokes. Quality spokes are made from stainless steel and often have a mark stamped on the head, with DT Swiss being the most common. Have the wheel rebuilt with new spokes, or get a new one. Your front wheel goes through less stress, so it should hold up for a while.

Things that don't flex break.

Steel has a fatigue limit. Low stress, such as the spoke's normal flexing under load, doesn't do damage, but the high stresses experienced by too-loose spokes at the elbow (where it turns at the flange) can cause fatigue and then failure.
posted by hydrophonic at 10:53 AM on June 28, 2012

Best answer: Last time I spoke to a bike mechanic about this, I was told three spokes was the maximum they'd replace before insisting on a new wheel. Looks like you're about there!
posted by backseatpilot at 11:57 AM on June 28, 2012

A new wheel may be the cheapest and easiest way to fix in the long run. I'm guessing your old spokes are fatigued and old enough that they're simply reached the end of the line. The hub flanges may also be too thin for the spoke bend, and spoke washers might have been called for. But it's not really worth a rebuild unless you have an emotional bond to the hub/rim.

Just get a new wheel.
posted by 2N2222 at 12:11 PM on June 28, 2012

Response by poster: Yeah, no emotional attachment, just cheapness. One broken spoke is annoying, two I figured maybe the trailing/leading spoke twin to the one that just broke had similar loading problems, but after the third one breaks? It's time to reach out to the hive mind.

And I'm glad to hear they're cheaper than I expected - in my 30 years as a biker, I've broken and replaced most everything else on my bikes (hubs, even), but I've never had to replace a wheel. Usually I get a feel for replacement parts through Nashbar, but they seem to only sell way overspecced wheelsets, so I'm working blind on the cost estimation front.
posted by Kyol at 12:33 PM on June 28, 2012

Have you considered building your own wheel?

Some years ago I got Jobst Brandt's book "The Bicycle Wheel", a new rim and a bunch of spokes. I followed the instructions in the book, taking my time. In the end I had a wheel that stayed true through all my single-track adventures -- I still ride on it. It's the back wheel, so I also had dishing to deal with. It's really not that hard, if you take your time.

I too have no shocks on the bike, and I have no fancy wheel stand or dishing tool -- I built it on the bike.
posted by phliar at 1:15 PM on June 28, 2012

Are you sure it's the spokes breaking and not the spoke nipples? I thought I had breaking spokes but it turned out to be a spoke nipple problem. Spoke nipples (the bits on the end of the spoke) are usually made of aluminium and can get brittle after a while. At first, I had the broken ones changed but then others broke and I decided to change the lot - spoke nipples are cheap as chips and I've had no problems for a year. It worked out way cheaper for the bike shop to replace the spoke nipples than to buy a new wheel, but get a quote for both first.
posted by guy72277 at 1:31 AM on June 29, 2012

Response by poster: Yeah, I've considered building a replacement wheel, but that's more of an off-season activity for me, given my schedule. I never have built one, though - and I've done most other bike maintenance at one point or another, but making a wheel has always eluded me.

And yeah, it's the heads thankfully. Since they're still mostly laced, they don't turn into little wire whips.

Anyway, I'll head to a couple of bike shops tomorrow and see what they've got.
posted by Kyol at 10:19 PM on July 1, 2012

If you do decide to build your own wheels--- something I think every shade-tree bike mechanic should give it a go at least once---do look at getting the Brandt book. He goes into detail about this problem and how to build to avoid it.
posted by bonehead at 9:41 AM on July 4, 2012

Response by poster: $68 later and I have effectively a new wheel. My tube, tire and cassette were pulled from my old one and everything's shiny again. I should have just jumped straight to that point after the second spoke broke, but you live and learn - I figured it would be closer to double what I paid.

($50 for the wheel, $10 for the labor, $4 for a new rim strip since mine had failed, then there's tax.)
posted by Kyol at 12:19 PM on July 6, 2012

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