After riding my Gary Fisher with badly worn brakes, there is an etch on one side of each rear and front rim. The etches go all the way around the rim and are deep enough for me to kind of put my thumbnail in a bit. Is this safe or should I get new rims? If I need new rims could you recommend some good ones please. I don't need anything too fancy like double walled rims, but I don't want junk.