Clydesdales/Athenas (200+ lb / 91+ kg) - Possible reason for my broken spokes

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Huzzah
07-29-08, 12:51 PM
About a month ago I was riding along and heard a lout pop so I stopped to check the bike out and noticed that I had broken a spoke on my rear wheel. I took it to my LBS and they fixed it in about 15 minutes (only $12:thumb:). I speak to mechanic about whether I am too much weight for the low spoke count (245lbs, 24 spoke rims) and he says maybe but let's give it some more time and see if more spokes break.

Flash forward to last Sunday, I'm riding an organized ride (Richfields Sweet Corn Challenge) and hear another spoke break, luckily only about 1 mile from the finish.

I went and picked the rim up yesterday and get to talking with the mechanic (a different one) and said the reason my spokes broke was that he could see my chain had popped off the large sprocket, hit the chain, and damaged some spokes. He went ahead and replaced all the spokes on the drivetrain side just to be safe. They only charged me for the spokes (~$6) and says that he would recommend that I go to a 32 or 36 spoke rim. I told him I'll wait and see if I pop any more spokes.

I remember vividly when my chain went beyond the large spoke and into the spokes - the bike came stock with no dork disk. I never thought to inspect my spokes, lesson learned.

I also can't say enough about the LBS - Century Cycles - as they have always been nice, honest, and friendly with me. Both times I took my wheel to get the spoke fixed they did it right then and there, and they charged me 1/3 what the rest of the local LBS's wanted to fix the spoke and true the rim.

Sorry for the long ramble, my main reason for posting was just to let people know that they should inspect their spokes for damage if the chain gets sucked into their spokes :lol:


Wil Davis
07-29-08, 02:26 PM
I would guess that there was insufficient tension in the spokes when the wheel was built; any machine-built wheel really has to be "hand-finished", and any good bike shop will do it as part of assembling the bike.

I build all my own wheels, but every single wheel I've ever bought pre-assembled, has had woefully insufficient tension in the spokes.

FWIW -

- Wil

TurboTurtle
07-29-08, 03:02 PM
Where did the spokes break? At the damaged spots or at the elbow? - TF


andymac
07-29-08, 03:04 PM
Wil Davis - A properly tensioned spoke is equally as likely to break as an under-tensioned spoke if you drop your chain off the inner cog. The spokes get a little nick in them that creates a weak point that is pretty much certain to break in the future.

Huzzah - You should make sure that the limit screw on your derailleur is adjusted so that you can not overshift, if you pull the cable by hand you should not be able to get the derailleur to move the chain off the largest cog. This will not prevent it entirely, the right combination of shifting, bumpy roads, too many chips the night before and forgetting to take the garbage out seems to be able to defy physics and wedge your chain between the cassette and spokes no matter how you adjust it.

Mr. Beanz
07-29-08, 07:19 PM
How in the workld did your chain go into the spokes with the dork disc on? Now that it's off, I can understand, but while it was on?

24 spoke whells only last so long for a big rider. I squeezed about 4k out of mine to get my money worth. I had a new wheel built way before it gave way.:thumb:

Huzzah
07-29-08, 10:12 PM
Wil David - While it's quite possible, I don't know this is necessarily the cause. Both spokes that broke were on the drivetrain side and the chain did get sucked into the spokes and the mechanic did find another spoke or two that showed damage from it.

TurboTurtle - Both of the spokes broke close to the hub, at the damaged spots on the spoke.

andymac - The limiter screw has been adjusted since that incident and has not happened again.

Mr. Beanz - I didn't take the dork disc off, it came stock without it. I'd be happy if I got 4k out of mine, I'm at about 900 miles now so it would give me some time!

Thanks for all the input guys!!