Originally Posted by
Doge
The rims are the biggest factor in wheel strength. See post and link above. ~400# 20 hole front - 15g center.
No, they are not for several reasons. First, the rim isn't attached to the spokes. It floats on the spokes. The rim deflects upward when loaded and decreases spoke tension as the rim slides upward on the nipple. It's not much but it happens constantly as the wheel spins. The tension on the
spokes adjust so that the overall tension on the wheel stays the same. Any flex in the system has a negative impact on the spokes...not the rim.
Second the wheel needs to be replaced when spokes start to break. Break a rim and you can easily replace the rim...if you have the same size...and the wheel is none the worse for it. Break several spokes and the wheel needs to be replaced or rebuilt.
Third, build a wheel with the strongest rim you can imagine...say a steel rim with a 1 to 2mm thickness like you find on many cheap bikes. Use weak spokes. You won't end up with a strong wheel.
Fourth, a rim on its own without any spokes can't resist much bending. Even steel rims are relatively easy to bend out of plane without a lot of force. The spokes bend the rim as needed out of plane with little effort. If they didn't, we couldn't true a wheel.
The rims purpose is to have something for the spokes to pull against and as a place to put a tire. But as a strength member, its role is very limited.
Originally Posted by
Doge
Before these carbon tubular rims I road alloy 32 (that I built), - pic here
Co-Motion Tandem re-build
I later wet to deep alloy 28.
On 36, 40 and 48 hole I broke spokes. It is very hard to get tension right on weaker rimes and large spoke count.
Deeper rims solved the "issues" .
Your comments run counter to about 100 years of knowledge. If you couldn't get tension right on higher spoke count wheels, you must have been doing something else wrong. It should be
easier to get the tension right on higher spoke count wheels because there are more spokes to carry the tension. Each spoke can have lower load and still perform the job. Functionally, most people are going to run the same tension independent of the number of spokes so the overall tension on the wheel is higher.