Bike Hugger 

I’ve never really known how to tell if it was time to replace a wheel due to wear on the rim… is there a quick answer or should I get lost and find out on a bike repair style site?

Most rims will actually have a distinctly concave feel to them when you’ve worn through. Some commuter/touring rims actually have built in wear indicator lines. However as part of the disc brake fanboy club I’m obligated to point out… When the weather turns nasty I don’t trust my life to rubber blocks and dirty hoops. It just *seems* like a bad idea, you know?

Hey, thanks man. I like discs too, but I like building up older bicycles more.

@Ben is right—you can tell with your finger that the rim has grooves in it and a concave shape. A good precaution is to check your pads periodically and remove the aluminum shards from it. Some brake pads pick up the shards more than others. I destroyed a rim in one ride once when a tiny pebble got stuck in the pad and scored the rim like a glass cutter.

Regarding discs and riding, the problem is when those go, you’ve got no braking at all, where you can at least grind to a stop with nubs of pads and even adjust it on-the-fly if necessary. In my recent [Cross race report](http://bikehugger.com/2010/09/bustle-in-your-hedgerow-1.html), I talked about reaching back and adjusting the brake mid-race. Not going to happen with discs. I’m not anti-disc, just don’t see the value over calipers or cantilevers. The [TRP Euro X](http://www.trpbrakes.com/) on our new Cross bikes have remarkable stopping power. I will say I despise V brakes.

high performance/racing rims usually don’t have the wear indicators. i suspect that the CPSC has a hand in it, but i couldn’t be bothered to research it

a worn rim will actually get wider as you inflate a tire, and it’s this deflection which is really fatiguing the metal. if you have good measuring calipers, you can actually measure the how much a worn rim splays out when you inflate a tire to pressure.  anything more than .7mm should make you nervous.  more than 1.3mm should put the fear of god into you.  you can’t predict exactly when a rim will blow, but there is always plenty of warning.

It bears pointing out that the kind of road debris that trashed Byron’s rim likely wouldn’t have had little chance to foul a rotor, and the damage would be substantially easier to repair.

Personally, I’m upgrading my Cross-Check commuter to a disc fork and wheel. After that I’ll finish the the Litespeed Blue Ridge three-season project they were meant for. In the meantime, I’ll have brakes that aren’t limited by my ears’ ability to stand the wake-the-dead howl that can’t be adjusted out of my cantis and the wear on the front wheel’s rim.

Correct. I’ve got Discs, Avid Juicys on the Bettie.