Bicycle Mechanics - Problem with spokes on a Mavic wheel

So this past february I got a new 26 inch wheel for my commuter. I figured I'd get something that can stand up to what I dish out to it and be reasonably priced. So I picked up a mavic at my LBS.

Since then I've put MAYBE 300 miles on that wheel and I've broken 5 spokes, replaced 4 of em (this last one I've not done anything yet since it happened yesterday) and had the wheel professionally re-tensioned and trued.

And still I've broken spokes.

After consulting my mechanic and Lenard Zinn's section in his road bike book on wheel building I've come up with 3 explainations as to why this may be.

1) Bad spokes

2) Machine built wheel not standing up to wear and tear

3) I'm doing too much to the wheel as it is. This theory doesn't bear out because I do just about the same amount of stress to the wheels on my roadie and they hold up.

here's the important info

Most of the spokes have broken on the non-drive side of the rear wheel. And all but one of the spokes that broke where tension (not static) spokes.

If anyone has suggestions of resources where I could learn about WHY this is happening and how to fix the problem. I'd appreciate it.

I figure I either have to replace the wheel or replace all the spokes. I'd prefer option 2 because then I can learn how to build a wheel (something I want to do anyway) and have an excuse to get a dishing tool.


Cheers,

Sev

I'm not an expert (proven by the fact that I posted a spoke question myself just this morning...), but I suspect the problem is simply in spoke tension: your spokes are either too tight or too loose. I'd bet too loose.

You could buy a spoke tensionometer from Park (~$50) or simply look at a similar wheel that is properly built and check the tune and feel (by deflection with your fingers) to see if your spokes are similarly tight.

When I built up my CX bike I bought mail order Ultegra hubs and Open Pro rims, but unfortunately I only shopped with the name of the parts in mind-- the wheels were machine built and turned out to be problematic. My rear wheel went through quite a few spokes until I read The Bicycle Wheel and tightened them all up quite a bit. That was over three years ago and I haven't broken a spoke since. I did eventually buy the Park tensionometer-- although not required, I do like having an easily quantifiable measurement.

Good luck!

-D

Two likely explanations:

1. A batch of defective spokes (but how did they all wind up on the non-drive side?)

2. Way too low tension. If the tension were too high, the rim would have buckled and/or all the broken spokes would be on the drive side which is under far more tension.

My money is on #2. Who built the wheel?

Sorry, double post. Forum problems as usual.

I bought a new set of wheels from eBay for my MTB. These were described as "hand-built" and never used. The tension on the spokes felt loose when I squeezed them, and when I measured with a tensionometer, it was about half of what I would have expected, so I re-tensioned and stress-relieved the wheels, and they seem to be OK so far (about 200 miles). Low tension is a recipe for spoke breakage. I would have a word with your LBS - ask them exactly what tension they would expect in the spokes.

- Wil

Sounds like a badly built wheel. If you break one spoke under normal conditions you should consider a complete retension of the wheel. If you break two spokes under normal conditions then you should definitely retension the wheel.

If this was a hand built wheel then take it back to the guy that built it, get your money back and find someone who can actually build wheels to build you another one. If it was machine built then consider yourself unlucky to get a badly built wheel and just get a competent wheelbuilder to retension it. Alternatively, buy yourself a wheel jig and learn to do it yourself, then if you break spokes in the future you can only blame yourself!

As to the low spoke tension. the last spoke to break broke just 15 miles after having the wheel professionally re-tensioned, dished and trued


UPDATE: talked to the LBS, they're going to RMA it and see what happens. Cheers all, thanks

As to the low spoke tension. the last spoke to break broke just 15 miles after having the wheel professionally re-tensioned, dished and trued


UPDATE: talked to the LBS, they're going to RMA it and see what happens. Cheers all, thanks

Sounds like the damage had already been done, and that last 15 miles was the last straw. If the bike had been ridden any distance with a "soft" wheel, I would be tempted to replace all the spokes as the damage doesn't occur instantaneously (the failure does, but the spokes flop around and get set up to break). It will be interesting to see how many of the original spokes break in the next several hundred miles.

Good that the LBS came through - but I would make sure the new wheel isn't another "softie". BTW (if it's not a personal question) how heavy are you, and what was the design of the wheel?

- Wil

This happened to a friend of mine. Broke 3 spokes within less than 500 miles on a brand new wheel. I talked him into letting me rebuild his wheel with new spokes and nipples. I ran into him on the bike trail yesterday. Wheel is still perfect. Hasn't even needed any touching up. The guy weighs about 250 lbs.

Machine built wheels can be problematic.

Bob

I weigh 170 lbs or so... on a standard double-cross spoked wheel... so *shrugs*

it was a Mavic mountainbike wheel I have a Specialized city tire on it... if that matters.