i used filler shit last season when I couldn't afford to replace my rear. I think I hit like glass or something because there was a tiny tear in the rear. The stuff was actually made for bicycles and was recommended to me by tomcat (chris). It honestly worked well for the rest of last season even though I checked the tire pressure daily since I was nervous. it's honestly something that no one wants to do (plug tire) but if you really can't afford $ for new rear, might make for a temp fix until you can afford new rubber