Michelin is developing a new tyre-and-wheel combination that can't blow out or go flat because it doesn't contain air.

Called a Tweel, it has fewer components than a pneumatic tyre, is immune to nails or a knife, and the tread lasts two to three times longer, Michelin says.

The Tweel would also eliminate the need for air pressure monitors, which will be required on all new cars and spare tires, adding weight.

Flexible polyurethane spokes and a layer of rubber that wraps around the spokes replace the air that normally cushions riders.

But it could be 10 to 15 years before cars on Tweels could be sold.

"It's not something that's going to change wheel transportation overnight," says Michelin engineer Bart Thompson.

"Still, that's no reason not to get excited about this technology."