Pirelli's tyre for 'safe blow-outs'
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• A new tubeless tyre being developed by Pirelli offers considerable safety advantages because of its anti blow-out and run-flat features. The tread pattern will be safer, claims Pirelli, because it will stretch the full width of the tyre and tyre grooves can be wider, so giving better water ejection characteristics.
The shape and thickness of the side walls offer protection from accidental damage especially that caused by severe kerbing and a deflated tyre will be able to run at speed without damage. Further, being a low profile tyre of about 50 per cent aspect ratio it allows more space for brakes, suspension and steering gear.
Initially, the tyres being developed will fit cars and their van derivatives, but the company expects to extend the new design principle to all types of tyre including those for goods vehicles.
The tyre consists of three parts; tread, belt and all-rubber side walls. It is immediately recognized by its almost triangular sections, the apex of the triangle being the narrow tyre rim and bead area. Unlike present radial and cross-ply designs the side walls of the yet unnamed tyre do not work under tension. Instead, the wall is under compression — bowing inward to the section centre line (see diagram).
The load on the tyre is divided equally between side wall and air, and because the air plays a less important role than in present-day tyres variations in tyre pressure are less critical.
Experience with prototype car tyres has shown that the stability and safety of the new tyre is superior to those of existing designs.