Spiked winter tyre which generates min. wear on road - has tread divided into outer cap with holes holding loose spikes and inner base with low hysteresis only at temp. above freezing point

摘要

Winter tyres have spikes held in radial holes in the treads. The tread in each case is divided into a lower base and an outer cap; the spikes rest loosely in holes in the cap; they are only stopped from moving radially inwards by a supporting element by the base. The base is made of a material which presents a greater resistance to penetration by the spikes at low temps. than at higher temps.; by this means and regardless of temp. the spikes are moved outwards by centrifugal force and touch the road surface when they pass through the outer surface of the tyre; if the temp. is above the limit concerned, however, they only stand out with a reduced prssure. The base part is pref. a rubber contg. styrene-butadiene. ADVANTAGE - Whilst the tyre retains the usual advatnages of spikes for winter conditions it minimises the wear on the road surfaces.