THE CORD TYRE.

Sun (Auckland), Volume I, Issue 136, 30 August 1927, Page 7

THE CORD TYRE.

WORK OF CONSTRUCTION. INTERESTING FACTS. Originally all tyre fabric was •oven. That is, the threads of iabric running the long way of the cloth were the same size and thickness as those running cross-wise. The so-called “fabric tjrc,” the predecessor of the present tord tyres, used this construction. The weakness of the fabric tyre was that no matter how carefully rubber was impregnated into the cotton, these threads running at right angles to each other were continually chafing and sawing at each other as the tyre flexed under the pressure of uneven roads. The faster the car was driven the more pronounced was this chafing of the fabric cords. This friction generate! heat in the tyre, and heat is the enemy of both rubber and fabric, and in time burned the life and resilience tut of it and the tyre broke cfown. It was possible, of course, to build the tyre so strong and stiff that there would be practically no rubbing of cord against cord within the fabric, hut that would have meant a loss of flexibility, which is the tyre’s principal reason for existence. Other things being equal, the more flexible and resilient a tyre is the better. This was demonstrated anew when the balloon tyre came into

Goodyear engineers found the solution in a cord fabric where the cords were only a little larger than those in the old fabric and were held together by cross threads so light and fragile that theye were broken under pressure in the curing moulds so that the tyreafter vulcanising came out without any cross threads at all. The fabric ply in the finished tyre then became a row of tough cords lying parallel to each other and each insulated from its neighbour by a coating of rubber.