We like ideas that use clever ingenuity to accomplish something that hasn’t been done before. At least, we think something like the PumpTube hasn’t hit the market, but we could be wrong. It’s a system that uses a special valve and an inner tube to inflate your tire at the exact pressure just by using the rolling motion of your wheel.
Air is drawn in from the atmosphere through a one-way valve, which sits in the valve stem. Instead of going directly into the inner tube, however, the air goes into one end of the tube-like pumping mechanism, which runs along the outside perimeter of the main inner tube. As the tire rolls against the ground, the pumping mechanism is compressed, forcing air into the inner tube. The resulting absence of air in the pumping mechanism creates a vacuum effect, drawing more air in through the valve.
That said, if the inner tube is already at its desired pressure (which can be set on a dial on the valve stem), no additional air is pulled in.
It’s a smart idea, and the better feature is that it can be used with your current tires. It is compatible with third-party 700c and 26-inch tires, and plans are for it to retail for US$30 to $55 per unit. You’ll have to wait for their Kickstarter to launch next year though, once they’ve perfected the design.