Originally Posted by
cyccommute
On impact the rim slides up on the spoke and the tension decreases slightly. The fact that the rim isn’t attached to the spoke is also the reason that I argue that rim strength has little to do with wheel strength. If the spoke were attached to the rim and under compression like a wagon wheel or a car wheel, the rim strength would be important. But when it is free to move, it provides very little strength. If we use stronger spokes, we can use lighter rims.
Good post. I don’t agree with this, though - rim strength is clearly very influential in the overall strength of a wheel. The existence of stiffer, more heavily built touring rims back in the day wasn’t merely an exercise in marketing. They really do help. I think this is completely consistent with your explanation of spoke fatigue, above: a stronger, stiffer rim will presumably deflect less on impact and impart less force to the spokes as a result. In the old days of course you basically had to pick: light but weak, or strong but heavy. Modern manufacturing means we can now have our cake and eat it too, at least to an extent. Of course a high spoke count with that strong rim is the best of all worlds. Still, even modern 24 and 28 hole road racing rims are amazingly strong. On sheer reliability per dollar, I’m not sure anything will ever compare to the 36 hole Rhyno Lite wheels I had on my LHT 15 years ago, but I wouldn’t hesitate now to go on the road for a week with the same wheels I ride and race road and cyclocross with.