Rim wear
 

Hi there,

I have a set of old "Matrix 550" mtb rims i use on my commuter/town bike. When they were new, i noticed there was a small line or ridge running almost in the middle of the braking surface round the wheel. Now 3 years and nearly 3500 miles of riding (wet + dry road use) the line is completely gone, both front and back. The rim surface is also concaved slightly where the pads hit it. I would say the wear is more apparent on the rear than the front but both show signs of age. Braking is still quite sharp and i occasionally sand down the pads, use disc brake cleaners on the rims. Bearing in mind this is used locally for just getting around town ~20miles a week and the bike is made up bits from used parts from my other bike, should i just wait until it fails/gets really bad or replace as a matter of urgency? Thanks...

If the "wear indicator lines" are gone the rims are now pretty thin and the eventual failure could be minor ( a small crack that makes braking a bit lumpy) or catastrophic (a whole section of the rim peels away leading to a sudden blow out.)

Replacement isn't urgent but should be done soon. You probably have time to find a good price on a replacement set. BTW, you must ride in some pretty harsh conditions to wear out rims in 3500 miles.

I'd say that it depends. For example, how's your dental coverage? It's just a matter of time before you blow a tire off one of those rims. Where and how fast you happen to be going when that happens is what determines whether or not continuing to ride on worn out rims was a good idea.