I'd have to go with Demp223. Yes debris does get in your tires, but not without you knowing it. The tires would have AT LEAST lost some air and required re-inflating. I took bran new fronts off of my 400EX, had been ridden in the GRASS only and found slivers of rubber from the unfinished inside of the tire. After time would have been balled up. It's rubber!! Marbles on the inside!!