The Slime Smart tube is functioning, I only wish I'd bought inner tubes that came with Strader valves instead of the Presta valves. The one inner tube will hold air enough to engage the Presta valve and the other inner tube well, it lets air out of the tube as fast as I pump air into it! I do not suggest filling with air( the tire and tube could explode causing injury) pump. So here's what I did I put the Smart Slime inner tube on the rear and just kept the old tube with the strader vale on the front. I won't be returning the tube though because when I inflate the other tube with enough air I think it'll function too.