Review on High Performance 700x32-47 Continental Tour Bike Tubes - 4 Pack with 40mm Schrader Valve by Jeremy Gulledge

I used this to get rid of a problematic Presto valve system on my daughter's bike. The Presto valve always leaked very quickly and the pump problem was too difficult to solve. I took out the inner chamber, bought a 7.5mm drill bit, bored out the wheels (it took me 2-3 minutes since the wheels are aluminum) and voila - you're rid of the cartridge valve for good. For years we put up with this system and now we've had enough of it on our last trip. We can now use any pump anywhere, at a gas station, in a rental system, the car's own pumping system, etc. The ease of use of a Schrader valve compared to a Presto valve is worth the money. The only problem is that the seller wants to sell 4 pieces as a set. This is a bike rack. MOST if not all 700 wheel bikes have 2 wheels. Then it's enough for 2 bikes :-)