I keep breaking spokes on my back wheel

girv73
girv73 Posts: 842
edited January 2009 in The workshop
My work bike is a MTB with the usual 26" wheels, built with AlexRims, spokes of some kind :shock:, own brand (Commencal) hubs and Avid BB5 disc brakes. I did run it on 2.1" knobblies @ 60psi and now I use 1.2" slicks @ 95psi.

As the subject says, I keep breaking spokes on the rear wheel: 4 went before Christmas on the knobblies and now another couple have snapped on the slicks, with another bent, and another loose. The spokes that break go both at the ends and in the middle. It's getting expensive to keep fixing!

At just under 14st I don't think I'm too heavy and my commute is all tarmac with just the usual gratings, potholes and so on, nothing serious.

So why are the spokes breaking? And why just the back wheel?

Are there "super strong" wheels or spokes I could consider?
Today is a good day to ride

Comments

  • JimmerG
    JimmerG Posts: 143
    Spokes usually only break on the back wheel (and usually on the drive side) because that's the wheel that has all the power from your legs going through it, and it tends to take more weight.

    In my experience spokes tend to break only on the elbow at the interface with the hub. MOST spokes break as they haven't been tightened enough. If there is ANY slack at all, it creates a shock load at the point the spoke turns through 90deg and it snaps.

    I've never had spokes snap in the middle or at the thread end.

    Maybe your rim has taken a bash in the past and to compensate for the warp, some spokes are tighter/looser than others.
  • whyamihere
    whyamihere Posts: 7,700
    Have the wheel rebuilt by a GOOD builder. It's dead.

    You may be better off getting a full wheel built. A Mavic XC717 on an XT hub with DT Competition DB spokes won't cost too much, but will last you forever if you take care of the hub. If you have a bit more money, the same wheel but with a Hope Pro 2 will be even more durable.
  • girv73
    girv73 Posts: 842
    whyamihere wrote:
    Have the wheel rebuilt by a GOOD builder. It's dead.

    My CFO is going to need more details ;):lol:
    Today is a good day to ride
  • whyamihere
    whyamihere Posts: 7,700
    Breaking spokes is a sign that the wheel was shoddily built. As JimmerG says, the spokes are too loose, which has caused them to become fatigued, and break early. If you carry on just replacing spokes as they break, you'll end up replacing the whole lot, and that will wind up more expensive. The wheel will still need a rebuild really, as the first replacement spokes may have loosened off by the time the last is replaced.

    A decent builder will probably do the rebuild for around £40-50, including spokes, or CRC are doing a 6 bolt XT hub with XC717 rim and DT Comp spokes for £77.49, and in my experience they build pretty decent wheels.
  • dennisn
    dennisn Posts: 10,601
    Once spokes start breaking on a wheel they will sometimes continue to break even though you have them replaced. IMHO riding, even short distances, on a broken spoke
    will put stresses on other spokes, weakening them and they may break in the future
    due to this kind of stressing. My advice is to simply replace the spokes the first time and MAYBE the second time one breaks. After that redo the wheel.

    Dennis Noward
  • girv73
    girv73 Posts: 842
    OK thanks folks, message received. I'll look into a new wheel I think.
    Today is a good day to ride
  • girv73
    girv73 Posts: 842
    I took the wheel down to my LBS for repair, the guy took one look at it and went "Nah mate, it's dead ... two ways". The rim is bent, and also badly corroded from winter road crap. New wheel time.

    At least they'll swap the cassette and disc rotor for free when I buy the new wheel :roll:
    Today is a good day to ride

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