I didn't think I would destroy a rim that fast either, but I live in an area with some pretty steep hills, there was construction on my route to and from work, so there was lots of grit and mud all over the place, and I live in the pacific north west, so it's wet all the time if it's not June, July, or August. Actually, I ride a lot of back country roads, so there is always some sort of dirt or grit from all the logging trucks. My rims, when wet, just sound dirty when I brake after riding for 15 minutes.