no the don't blow them , the go out to ride the bike the next day and the tire is flat and they say "but I didn't do anything" yeah right, probably rode through a field or something, not many sidewalks here so there are thorns, I tend to ride on the side of the rode because I don't want a flat LOL. What this city needs is some roads on the side just for bikers. to keep them safe and they can ride without getting flat tires everyday LOL