The tyre with a replaceable tread - produced by the Pirelli company of Italy - was demonstrated at Zandvoort, Holland, October 31.
SV. Tyre casing shows ridges.
SV. Rings of tread to fit onto casing.
SV. First ring is fitted.
SV. 2nd ring is fitted.
SV. Tyre is turned over.
SCU. 3rd ring is fitted.
SCU. Tyre is inflated.
CU.PAN. From inflated tyre PAN to heavy duty tyre.
SCU.PAN.Car with new tyres fitted, moves off.
LV.PAN. Negotiates bend.
SV.PAN. Performs zig-zag.
LV.PAN. Brake power is demonstrated by comparison with another car with ordinary tyres.
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Background: The tyre with a replaceable tread - produced by the Pirelli company of Italy - was demonstrated at Zandvoort, Holland, October 31.
A number of advantages are claimed for the new tyre, known as the BS 3. Unlike conventional tyres, the BS 3 consists of a long-life casing and three separate tread bands. The casing or tread bands can be replaced separately, and relatively inexpensively, if either unit becomes worn or damaged. It is not necessary to buy a complete new tyre, as with conventional types. A car can have the treads on all 4 wheels replaced in 10 minutes, without removing the casing the wheel.
Different kinds of tread band are available, and for icy roads special tungsten-carbide studs can be fitted into the tread, giving - it is claimed - excellent road-holding qualities.
The casing is of larger diameter than the tread bands, which are fitted while the casing is deflated. When the tyre is inflated, both casing and tread bands are tightly locked together. To prevent the tight grip becoming loose through stretching, and unstretchable belt of metal wires runs through the tread bands.
Other safeguards are built in to avoid any possibility of lateral or circular slipping between tread and casing, and the BS 3's braking, cornering and road-holding are all exceptionally good, the makers claim. A special safety valve is fitted on the inner tube to reduce "blow-out" and puncture risks.