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Question about wheel repair(4 posts)

Question about wheel repairKurt H
Jun 6, 2002 5:50 AM
Hey folks,
Need a little advice from the more knowing group.
I just broke a spoke on the rear wheel of my commuter yesterday. These wheels have MAYBE 1500 miles on them. I bought them slightly used on another bike. The previous owner had three spokes break on him on one trip (the only trip he took on the bike, I might add) on the same wheel. The wheel is a 36 hole Cannondale Expert hub laced to a Mavic T519 rim taken off of a Cannondale. I'm going to guess this is a machine built wheel, which I've read numerous suggestions on the board about commonly needing to be properly tensioned by a human hand. I'm looking at two options for the repair:
1) Replace the spoke, have the wheel re-tensioned completely (this part I'm going to do either way), and keep going.
2) My current inclination - Have the wheel completely rebuilt by my LBS using all new spokes.
I guess my question for you is whether option #2 is overkill. I wonder if the remaining spokes on the wheel may have been damaged from poor tensioning in the past and being ridden in that state? If that is a reasonable possibility, the spokes are out of here.
Keep in mind that I commute through some...ummmmm...less attractive areas on the way to work, commonly with a laptop on my back. I was glad to be almost home when the spoke broke yesterday. If it would have broken in some of the other areas I would have been seriously concerned.
Any advice would be appreciated.
Kurt
re: Question about wheel repairbob_vanderhaus
Jun 6, 2002 6:01 AM
If you have the time and money, why not rebuild them. If dude before you broke 3 spokes, this is a good sign that they were not built properly to begin with. You can never be sure it is a bad build though. I had a set of wheels where I broke 2 spokes in 500 miles, and then have never had another problem and that was over 10,000 miles ago!
I'd recommend the complete rebuild.Spoke Wrench
Jun 6, 2002 6:33 AM
You've already had 4 of 32 spokes break. That's 12%. My top priority in a commuter bike is reliability and right now I don't think you have that.

You know this wheel has already been retrued at least once and at the very least needs a major going over again. It's actually not that much more work to cut off all of the old spokes and start over from scratch. The advantage is the wheelbuilder can gradually and evenly build tension back into the wheel resulting in a much more reliable structure.

If I did the work, it would cost you from $45.00 to $65.00 depending on which spokes you specified.
low tension = rapid spoke fatigueoff roadie
Jun 6, 2002 9:25 AM
Like you said, its probably machine built. 36 spokes can only be tightened so much on a road rim anyhow, and if they are 14g staight spokes, there may be no way the rim can support the tension needed to keep them tight.

I'd bet the breaking spokes are on the left side, where the tension on rear wheels is always low, by design. This can result in spokes breaking duie to fatigue, since they go slack faily easily and then tneh flex as tension returns. Replacing the broken spoke and properly tensiong the wheel would help a lot- even if some spokes are already partly fatigued, propper tension will extend thier life greatly. Replacing all the spokes on just that side should solve the problem completely- the current left spokes are all gonna be somewhat fatigued, but the other side should be OK.

If you replace the left spokes with butted spokes that have a thinner center section than on the right side it may help longevity a great deal over simply duplicating the exiosting setup with new spokes. Thinner spokes will stay taught even with the reduced tension. I'd consider a center 2 gauge sizes lower than is on the right- if you have straight 14 on the drive side, use 14/16's or 15/16. If you have 14/15, use DT revolutions (14/17) or 15/17 (Ritchey makes em, I think) spokes.