Airless or hot air?

The last airless-tyre story to appear in motoring.com.au was in March 2013, as a small All-Terrain (ATV) manufacturer announced details of a workable design dubbed Polaris NPT (for non-pneumatic tyre). The system had performed convincingly in extensive testing regimes that included 8000km of driving after being shot by a 50-calibre bullet, covering 1600km of that with an imbedded railroad spike.

That was then. Today, the Polaris NPT seems to have gone silent, despite hopes that it would be on the market by 2014.

Now, Korean manufacturer Hankook is out with the news that it has completed high-speed testing of its airless tyre equivalent, the iFlex. It is, as Hankook unabashedly admits, its fifth attempt at mastering the concept.

The non-pneumatic iFlex tyre employs a similar system to other airless designs, with a compressible matrix of a special material that emulates the action of a conventional tyre.

The secret is in the material used. Hankook gives nothing away except to say it is energy-efficient to manufacture, easy to recycle and halves the number of steps required for manufacture. It also enables multiple colour choices, including vibrant green and orange examples.

In testing, the Hankook iFlex tyre addressed five vital criteria: durability, hardness, stability, slalom and speed.

Fitted to an electric vehicle, the iFlex successfully managed a top speed of 130km/h without damage, while matching a conventional tyre in all other respects.

Despite these promising results, Hankook at this stage is not saying anything more about the testing, or when the iFlex might reach the point of manufacture. It does point out that numerous tyre-makers including Michelin and Bridgestone are also working on the Holy Grail of tyre design.

Really, as far as the practical, functional airless tyre is concerned, it only seems like a matter of time before somebody (excuse the pun) nails it.