Originally Posted by
Vodalus
I'm a longtime cyclist but just started commuting about 6 weeks ago. About 5 weeks ago i switched out the tubular wheelset on my bike for some 36 spoke clinchers. Last saturday I went back to have my LBS make sure the wheels are still true.
Spokes don't break in properly built wheels for the first few hundred thousand miles unless you shift the chain into them or something similar. Merely crashing and bending a rim usually doesn't hurt them.
I've put about 380 miles on the wheels since i bought them; 95 of those in the week since my LBS trued the wheels. Today on my way home i broke a spoke on the rear wheel. Thankfully i was only about a mile from home and was able to limp back.
You bought shoddy wheels.
You might have gotten lucky and broken the one spoke with a manufacturing defect, although you probably just discovered that the wheels
1) Weren't stress relieved. Expect the other drive side spokes to fail until you've replaced them all (they all have about the same residual stress from the elbow forming operation and see the same fatigue cycles at 750/mile).
2) Weren't tensioned enough. If not corrected you can expect the non-drive side spokes to fail individually as they flex back and forth like a paperclip you've decided to break.
I ride with a pannier strapped to my rear rack. it probably weighs in at 20-25 lbs most days. Could the extra weight have contributed to the spoke breaking after this little time?
It contributed. The number of fatigue cycles survived are a function of average stress and the amount of variation. Average stress issues mostly come from parts of the elbow which were never taken pat their elastic limit and therefore have parts with high residual stress from the forming operation. Variation comes from the amount of weight you + bike + luggage put on the wheel as the bottom spokes unload with each revolution.
The root cause was other construction defects.
Or, could this have been some issue with the wheels themselves or with the way the wheels were trued by the LBS? I'd just like to figure out whatever I can to make sure it doesn't happen again in the future?
Learn to build wheels and make a set around nice serviceable hubs (Shimano Ultegra would be a fine choice for road hubs since you can get loose bearings, cones, and replacement freehubs) with commonly available rims and DT Competition 2.0/1.8 spokes. When you wear out the brake surfaces on a rim or bend it in a crash de-tension the wheel, tape the replacement next to the existing rim, move spokes over one at a time, and then tension like building a wheel from scratch except you won't need to stress-relieve. The spokes should be fine for the first few hundred thousand miles unless you get something hard like a chain stuck in them.
I think one of my mistakes is not knowing how to true wheels and replace spokes on my own. tomorrow that will change.
You want to read _The Biycle Wheel_.