Subject: RE: Broken Bike Spoke A bicycle wheel is really an extreme mechanical device in terms of strength to weight ratio. The spoke are tensioned above the yield limit and go thousand of tensioning-detensioning cycles per mile This fatigues the spoke material causing it to become brittle and ultimately break. Bicycle wheels are truly an engineering marvel. But they are right at the limit of breaking all the time. I would guess that this is a rear wheel and has 24 or fewer spokes. You probably ride these wheels all the time. And you weigh more than 175 lbs. And you have owned the wheels 2 or more years. Congratulations, you just wore out a spoke. It happens.. One thing you can do to improve the life of the spokes is to be sure that the spokes are equally tensioned to the correct tension specification. You can get an iPhone app for $5 that is very accurate. When you true the wheel, you should be able to achieve >0.02mm variation radially and laterally and tensions all within 6% of specification if the rim itself is true. Spokes experience greater fatigue if they are too loose or too tight. You want them all bearing equal load. You want them not to ever go completely slack under load either. The spoke at the bottom should remain in tension under the normal vertical load of the rider. If you want to never break another spoke, get a set of 36 spoke 3 cross wheels with 2-1.8-2 mm double butted spokes. These are not particularly aero and not light but they will be more durable than a 24 spoke racing wheel. There is just more load margin in each spoke than in a 24 spoke racing wheel. TW |