Originally Posted by
FBinNY
I left 0.1% for non-structural failure, so you might be in that band. Or it's possible that you're replacing rims prematurely, but that doesn't change the fact that the vast bulk of rim failures are for reasons other than brake track wear.
Typical rims are designed to allow track wear of about 1mm. I ride tubular rims with total wall thickness of 0.7mm and typically get over 20,000 miles out of rims before some mishap kills them off (never had a front rim failure of any kind).
Anecdotal evidence aside, I stand by my statement that very few road rims last long enough for brake track wear to be a factor.
Tubbies are completely different. What happens on a clincher is that tire pressure forces the hook at the edge of the track out. The first thing you notice is that thump, thump, which is a bulge in the track from tire pressure. I don't discard them until they thump. However you are right that few cyclists ride in the wet grit like we do here. Lots of people seem not to ride in the rain at all. But among those who do ride in the rain, track failure is by far the #1 cause of rim replacement. In 15 years of large group rides, I remember one person who missed his bunny hop (too slow) on a 4" pavement edge and dented his rear rim. Another rim got a screw all the way through it. Another rim corroded away on the inside. Bet you don't see that much! But all the rest that I know of failed from track wear.
I guess we are pretty edgy out here, but .1%? That's a real honor. I gotta say, I do ride with a bunch of crazy, hard riding characters. We belong to the largest bike club in the country, but sometimes when we go out, we don't see a single other cyclist.