SERVICE FROM TIRES

Evening Post, Volume CXIV, Issue 92, 15 October 1932, Page 17

SERVICE FROM TIRES

SPEED THE ENEMY

HOW WEAR • INCREASES

Despite tlio fact that demands on tiros have increased enormously in recent years, their quality has outstripped these needs, and the motorist to-day gets '*six tinies as much mileage out of a tiro as he did fifteen years ago,',' according to Mr. J. F.. O'Shaughnessy, vice-president of the United States Kubber Company.. Declaring that in five years the average horsepower of twelve popular makes of cars has risen by 80 per cent.,; and the average weight 'by 25 per cent., while the size 'of wheels has decreased by 20 per cent., Mr* O'Shaughnessy says:— . .

"All these ;changes—more power, more weight, .more speed, faster, acceleration, more wheel revolutions—contribute to faster tfcad wear. Yet in this period the automobile tire not only has mot these requirements, but has been improved to the point where it is, actually 70 per cent, better than the tire, that cushioned the 1927 car." . -. :■ ■. ' ■ .

Hoads have constantly been made, better,, of course, but this very improvement has tended to increase tire wear, as it permits higii speed. And speed, according to Mr.' O'Shaughnessy, "is the worst enemy of a tire." ■ ■..; , He points, to tests made in various parts of America showing that increases in speed cause definite increase in tread wear. For instance: Assuming that a tiro gives v 100. per cent, mileage, at thirty miles an hour, an' increase to fifty m^les reduces the mileage to 75 per cpnt.; at sixty-five miles the: mileage drops to 63 per cent.,; and at seventy miles to 55 pej: eent.--rthese figures all based on a constant normal temperature i of 70 degrees.;'. , ■'■; " , .?So. it is evident that good, rqads.and their accompanying speed are iot like--1- to lengthen the life of El tire, "Mr. O'Shaughnessy asserts. "It is a inattor.:of interest to kno^? that it is .not the concrete road of to-day, but the old dirt'road (t£ yesterday that was easiest on tire treads." ; l ■He says that the industry,has utilised every aid of science, maintaining' a corps of experts constantly at work in laboratories and on the" road to mako possible ever -bettor, tires.