Michelin's On A Roll...

Research engineer Bart Thompson said: "It's the idea of keeping you going after a puncture. The logical answer is to work towards something that operates without air. This is the holy grail for Michelin." The Tweel's rubber is fixed to the hub and takes the strain through strips that radiate outwards. A similar concept, the Airless Tyre, also debuted, using external bands - green in our picture - to spread the load. Thompson added: "We'll test them on low-weight, low-speed applications like wheelchairs, then think about cars."

The third prototype was the Active Wheel, which shows how a car's suspension parts can be fitted inside a wheel to boost passenger space. All three technologies are likely to appear over the next five to 15 years.