The bicycle tyre that is self-inflating

A new design of self-inflating bicycle tyre promises to do away with the need to ever carry a pump.

The PumpTire design draws air through a valve into a thin tube, called a lumen, which runs around outside of the tyre.

As the wheels turns, the air inside the lumen is forced into the tyre and inner tube.

The rider can even alter the tyre pressure with a simple adjustment to a dial on the handlebars.

Why do I need self-inflating tyres?

The PumpTire is not a run flat design and cannot guard against punctures, but bicycle tyres need topping up because they lose pressure due to air molecules escaping through the rubber sidewalls.

PumpTire promises fewer pinch flats, an end to pumping, less time getting ready and more time in the saddle.

The valve assembly works by screwing it into the valve stem on the inner tube. Although the valve stem looks similar to standard Presta/Schrader stems, it is a custom design that allows air to enter the tyre before being pushed into the tube. The valve is either a fixed pressure valve that shuts off once the desired pressure is reached or an adjustable valve as shown in this illustration above. Turning the valve, adjusts the pressure higher or lower to reach the desired setting. The top of the valve is compatible with a traditional pump.

Calling all dragons…

Kickstarter is an online Dragons’ Den that allows people to pledge modest amounts of money to help entrepreneurs get their designs into production. In the case of the PumpTire, an investment of $45 (around £30) will buy one set when the tyre goes into production. The recommended retail price is expected to be around $65.

A spokesperson for the Environmental Transport Association (ETA) said: “This is an interesting idea, but it remains to be seen whether the benefits of the PumpTire outweigh the complexity it adds to the bicycle.”

Cycle insurance

Cycle insurance from the ETA includes, amongst other things, new-for-old, third party insurance (in the case of an accident you may need to seek compensation or even deal with a claim by someone else), personal accident cover, race event cover and if you suffer a mechanical breakdown, they will come out and recover you and your bike. Get an instant, no obligation quote below.