CARE OF TYRES.

Putaruru Press, Volume VI, Issue 230, 29 March 1928, Page 7

CARE OF TYRES.

A STITCH IN TIME. Tyres are not intended to stand up to stunt performances. The sudden braking and sudden acceleration of the vehicle is not good for the tyres. These stoppings and rapid starts do more to wear and overstrain tyres than miles upon miles of ordinary careful driving. Often tyre trouble, which may become seriously expensive, starts with the stunting, and once started, tyre trouble has a way of developing rapidly. The fabric which forms the basis of the tyre, and through which the whole of the engine power has to be transmitted in the case of the rear tyres has, as will readily be seen, an enormous strain constantly imposed upon' it. It is only because of the number of the strands of the fabric and the careful tensioning of them in manufacture, that each bears its little share of the enormous combined load which the tyre has to carry, and of the big pressures which the propulsion of the car and its load imposes upon it.

If a few of these strands become broken, it is obvious that a great strain is imposed upon the others. When a tyre is gashed—say, with a sharp flint or a pieete of glass, or any other sharp substance on the road—it bulges slightly at that point. It is prevented from bursting because the remaining strands, although sufficient to protect the inner tube, are not strong enough to prevent distortion of the cover. But these overstressed

strands are being subjected to undue strain, and a big bump or an obstruction may at any time cause them to ! give way. Even if such is, fortunately, not encountered, the gash in the outer surface and through the first, and perhaps through the second layer of fabric, will allow wet to get in, and dirt and grit to lodge in the cut. This means further very heavy strain. It may not be properly ap-

preciated that the presence of water in a gash in a tyre has a most damaging effect, not so much because of the rotting of the fabric, although this is very serious, but because of the enormous bursting pressure set up when part of the wheel rolls round between the road surface and the , wheel. Then the pressure is very great, and the water, being non-com-pressible, is forced along in the fabric with great disruptive pressure and increases the damage. It is this which makes it so necessary for any small cut or gash to be immediately attended to. Carefully going over the tyre and mending small cuts and gashes before they are subjected to pressure and dirt and water will make the effective life of the tyre enormously longer.