PumpTube keeps itself inflated with wheel rotation

For some riders, slow, persistent leaks can be annoying, especially when they flat you out halfway to work or school and you don’t have tools. If a particular inventor’s newest gadget works out, though, that might be less of an issue in the future.

That gadget, as recently announced, is called PumpTube.

Developed by inventor Benjamin Krempel, it’s part of a family of products called PumpTire: bike tires that keep themselves inflated with the aid of the wheel’s motion. It’s a solid idea, of course, but certain drawbacks presented themselves for some cyclists. For one, those riders would be restricted to the PumpTire itself as their only tread choice; for another, once that tread wore away, the tire’s pumping mechanism would be affected, making it less useful.

Recognizing those issues, Krempel developed an alternative, using the most intuitive solution that availed itself—employing the same self-pumping idea, but putting the mechanism inside the tire.

Hence, PumpTube.

Its function is made possible through the use of a one-way valve, attached to the valve stem that draws in air from the surrounding environment as the bike speeds along. Instead of sucking that air directly into the tube, however, it’s drawn into the far end of another, smaller built-in tube, which is then pumped into the tire’s tubing as the tire’s movement compresses the mechanism. A vacuum created by the pumping itself then draws in more air, continuing the process until the tube is fully pressurized.

For riders who like to keep lower air pressure in their tires over the winter, it may present other drawbacks for that reason, of course. For those annoyed by repeated pinhole leaks, though, it’s designed to be a solution, compensating for the pressure lost by slowly seeping air.

According to plans, the PumpTubes will be combatible with 700c tires, will retail between US$30 and $55, and will be launched via a Kickstarter campaign in the new year.