Cross-ply tyre
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A new Dunlop cross-ply tyre made in sizes suitable for cars and vans has a flat tread claimed to give 10 per cent more mileage. To achieve the extra mileage, Dunlop have designed the 075 as the new tyre is known, with a concave moulded tread. This gives the tyre a flat tread with more even contact pressure when the tyre is inflated and under load. Added to this, the 075 tread is up to 7 per cent wider, and it is these two features which contribute to the tyre's increased mileage performance.
The new tyre embodies two improved features in the tread deep wide drainage grooves and rib grooves with a bulbous base. Both these features are claimed to give 20 per cent better peak braking performance on wet roads.
One reason for the falling-off in wet efficiency of tyres when part worn is that the grooves in the tread pattern naturally lose capacity as they wear down and cannot clear the same volume of water as a new tyre. To counteract this, the intermediate grooves in the D75 pattern are moulded in such a way that they are wider at the base than they are at the tread surface. Therefore as the tyre wears, the mouth of the groove grows wider and the tyre retains its capability to deal with large amounts of surface water. This "bulbous base" tread groove and the wide central channels are both design features which are exclusive to Dunlop and are the subject of patent applications.
The D75 employs a stressfree casing of high-strength rayon and also has wear indicator bars which become visible when the tread wears down to near legal limits.
Made by: Dunlop Co. Ltd., (Tyre Division), Fort Dunlop, Erdington, Birmingham, 24.
Price examples: 5.20S 10 tubeless £5 16s; 5.20-13 tubeless £6 8s 7d.