Bike FAIL

girv73

I've snapped three spokes on my back wheel somehow :shock: ! What made it even more fun was that the shape changing back wheel caused the chain to leap off the cassette and get stuck, while navigating a major roundabout (Carlisle Circus, Belfast) in rush hour, leaving me to do roadside repairs and limp on home. What fun!

I've never snapped a spoke before in all my years of rigid framed mountain biking, so why would this happen to the commuter bike which has barely seen a kerb never mind a mountain trail? Cheap wheels? My enormous mass? Does this just happen?

-liam-

Spokes have come loose ? Do you check them for tension at all ?

girv73

Nah they've actually snapped in two. It's in the LBS for repair, I'll see what they say about the rest of the wheel.

drewp2008

d0nt think the br0ken wheel caused the chain t0 jump 0ff the cassette. m0re like the 0ther way ar0und.

girv73

The chain went outwards towards the mech, not into the spokes. There was a bang first, then the chain went.

msw

When you say "snapped in two", do you mean in the middle of the spoke? 'Cos that's *really* weird, you'd expect them to break at the rim or the hub end. I've had a few go in the back wheel under heavy braking or acceleration and concluded that it was a combination of 1) lots of weight in the panniers and 2) the cheap wheels that came as standard on the bike. Bought a set of Mavic Open Pros with more spokes and it hasn't happened since.

girv73

Yep, three of them, snapped in the middle not right down at the hub or rim end. Cheap wheels I guess.

System_1

Sounds to me like you've picked something up in your rear mech which has whipped up, cut the spokes and unshipped the chain. Spokes nearly always break through fatigue either at the rim or hub like msw says, and its very unlikely to break 3 at the same time without some kind of impact to the spokes themselves. Also broken spokes won't unship a chain. Doesn't matter how out of true a wheel goes the hub will always stay in the same position within the dropouts so the chain would have no reason to unship. You could cut every spoke in your rear wheel the hub isn't going to move.

gtvlusso

I have broken spokes before, but never 3 of them at once - mostly due to wear and tear/rust....Takes a minute to replace them though.

chuckcork

System wrote:

Sounds to me like you've picked something up in your rear mech which has whipped up, cut the spokes and unshipped the chain. Spokes nearly always break through fatigue either at the rim or hub like msw says, and its very unlikely to break 3 at the same time without some kind of impact to the spokes themselves. Also broken spokes won't unship a chain. Doesn't matter how out of true a wheel goes the hub will always stay in the same position within the dropouts so the chain would have no reason to unship. You could cut every spoke in your rear wheel the hub isn't going to move.

If you cut every spoke in your wheel you'll be left with a rim and a hub, it wouldn't be a wheel anymore.

girv73

Maybe I did pick up something in the mech then, though there was nothing obvious on the bike or on the ground (I checked the road for any bits having fallen off!)

Could I have broken a spoke earlier on (days, weeks ago?) and this put more strain on the remaining spokes which eventually failed?

Is it easy enough to replace a couple of spokes and re-true the wheel by yourself? I've not much experience with wheel problems, so I've left the wheel in for repair this time. But I'm handy enough with the rest of the bike maintenance.

ansbaradigeidfran

chuckcork wrote:

If you cut every spoke in your wheel you'll be left with a rim and a hub, it wouldn't be a wheel anymore.

And you could use the half-spoked rim as a 'crown of thorns' in your school's Easter Day production, too.