San Francisco startup PumpTire has recently created a lot of buzz with their new self-inflating bike tire design. By directly incorporating a pumping mechanism into the tire, the PumpTire may not keep you from flatting while out on a ride, but will eliminate the need to check your tire pressure before you set out, even if your bike has been sitting idle in the garage for weeks.
Each PumpTire is made up of a special outer tire, a detachable valve, and an inner tube which clips directly into the tire. A small diameter hollow tube, or lumen, runs along the circumference of the tire and draws in air from the atmosphere as you ride.
As your wheel rolls forward, the lumen collapses, pushing air along through to the valve system and into the inner tube. Once the desired tire pressure is reached, the valve shuts off the air pathway. A small air filter stops water and other particles from entering through into the tire.
As the PumpTire is not a run-flat tire, it will only save you from having to inflate your tires from disuse, not from puncture. With a special tire and inner tube setup, a bit more work may be required to replace a flat on the go. Although puncture resistant, the lumen is subject to damage that may compromise its ability to pump. The company is looking to incorporate Kevlar type material into this hollow air tube to help prevent any damage.
PumpTire self-inflating tires work on standard rims so you won't have to buy new wheels. The company is looking to produce two tires to start, one for casual cyclists (26" x 1.5") with a 65 psi maximum pressure and a higher performance tire for bike commuters (700c x 280mm) with a 100 psi maximum pressure.
PumpTire is currently running a Kickstarter campaign to raise $250,000 to fund the production of the first 5,000 self-inflating tires. For that sum, I would have loved to see the company instead turn to Angel Funding (even though that may mean giving up some equity) from someone in the business to help solidify their use case and go to market strategy.
So would you buy a new set of tires just to avoid inflating them before you head out on a ride?