Long time lurker, first time poster.
Something I have been wondering lately: Are there any reliable signs predicting that a rim is about to fail? What is the normal life span of an aluminum rim, anyway?
Reason for the question is, I have Mavic CXP14 rims on my triathlon rig, and I use them both for training and racing. They have in the order of 10.000 km on them, and though there aren’t any visible signs of unusual wear, I’d hate for them to give up on me during a 70 kph descent or something…
An alu rim will not suddenly fall apart. The brake surface will gradually be thinner, until it’s completely worn out. For a tubular rim, it will only be weaker. If the brake surface is completely worn out on a clincher, the tyre might loosen or the tube might explode. If the braking surface is OK - no problem.
Aluminum rims will suddenly fail in two ways. One is that the brake track wears through and two is that a spoke pulls through. I’ve seen both. Typically you will see small cracks near the spoke before failure. With the braketrack wearing out this usually only occurs with clinchers and only with lots of riding in the rain or with brake pads meant for ceramic coated rims being used on aluminum rims.
I have a Mavic GP-4 tubular rim, which is 20 years old, with close to 40K miles on. I was actually looking at it this weekend and I’m thinking it should probably be retired as the braking surface seems to be very worn.
Aluminum rims will suddenly fail in two ways. One is that the brake track wears through and two is that a spoke pulls through. I’ve seen both. Typically you will see small cracks near the spoke before failure. With the braketrack wearing out this usually only occurs with clinchers and only with lots of riding in the rain or with brake pads meant for ceramic coated rims being used on aluminum rims.
Thanks for your replies, everyone. Sounds like my trusted CXP14’s should still have some lifetime left, since the breaking surfaces don’t look excessively worn.
Maybe it’s time to start another 5 sec poll: Who’s had rims fail on them, what material, and after how many miles?