Originally Posted by
OldBike876
Here's the question: why only rear spokes? I've never busted a front spoke, only a rear. I'm a big, fat guy, which probably explains the snapping spokes, but I would have expected fronts to break as often as rears.
Any thoughts?
Spokes fail due to fatigue, with the number of cycles survived a function of average stress and magnitude of variation.
You have about 750 stress cycles per mile from spokes losing tension passing the bottom of the wheel as the rim deflects and unloads them.
Heavier riders increase the magnitude of the cycle by bending the rim farther.
With more weight on the rear wheel it has higher magnitude cycles.
The drive side has higher tension than the non-drive side and therefore average stress making failures there most common.
Regardless, if you're breaking spokes your wheels are not well-built.
As manufactured, spoke elbows have high stress because the entire elbow isn't taken past its elastic limit. If you don't stress relieve them they'll fail. If you do they can last over 300,000 miles provided you don't get anything caught in them or nick them overshifting your chain past the large cog.
You can also have problems at the nipples when they can't pivot enough to point at the hub spoke holes and don't bend the spokes to compensate.
These things usually aren't addressed in machine built wheels, although you can buy a Holland Mechanics machine which stress relieves.
They may or may not be addressed by individual mechanics, You need to build your own wheels or delegate to a one person wheel building operation where the hands that earned its reputation build your wheels; e.g. Peter White.
Few mechanics could build good wheels fast enough to be profitable before the rise of factory wheel sets. Most compromised building bad wheels profitably. This has gotten worse.