Arizona republican., 1919-09-14
UNIVERSITY TESTS
 TIRE RESISTANCE
 FUR MANUF FACTURER
Automobile Company Car ries Question of Rolling Resistance into Labora- tories of Eastern School

into the laboratories of an eastern university prominent automobile company has taken the mooted ques- ton of rolling resistance of tires and emerged with an answer that will be or inc greatest interest to hundreds Of thousands of automobile owners every where.
 One of the chief problems which con- tinually confronts automobile manufac- turers is the reduction of the rolling re- sistance of their cars and the resultant case of riding and economy of maln- tenance- Tire equipment is the import ant factor in this consideration.
 Rolling friction is the resistance to motion which a body offers when roll ing on a surface. This friction is meas 11red in terms of force expressed in pounds. Low rolling resistance, it is pointed out, means minimum pull up- On the engine and comparative reduc- tion in the gasoline consumption. Roll ing resistance is regarded as the su- preme quality test of automobile tires.
 Accordingly the prominent automo- bile manufacturer in question requested the technical engineers in the research division of the university to conduct a scientific experiment to determine the comparative rolling resistance as or fered by different makes of tires.
 Two leading makes of tires were chosen by a process of elimination for the final test The usual apparatus consisting of a rolling drum which fur nished the surface of contract for the tires, and a dynamometer, was used The dynarnometer measures the resist ance to motion in terms of pounds.
 A set each of Firestone non-skid and Firestone triple tread cord tires, with similar sets of tires made by another prominent tire company were attached to the rear wheels of a touring car in separate tests. The tires were sub jected to loads of 5S5.935, and 1,2Ss pounds each, and to pressures of 30, 45 65, and 90 pounds, and run at speed of 5 20. 3O and 40 miles per hour.
 Tn terms of percentage, according tc the results afforded by this experiment the cord tires of the competitor offered a rolling resistance which was sixteer per cent greater than that offered by the Firestone non-skids, and twenty five per cent higher than the Firestont triple tread cords.
 "Of course it is highly gratifying tt me to learn that Firestone tires made the best showing in this test" said J Webb Smith of the Firestone Tire ani Rubber company branch yesterday But it only confirms my personal ex, perience of many years. have ofteI remarked upon the easy riding qualitie. of Firestone tires, and always contend cd I could ride farther on them on les' gasoline than on any other tire. I an pleased, however, to know my persona observation has been verified by exac scientific experiment.
 "A surprisingly large percentage O owners never give the question of roll ling resistance a moments thought, bu one does not need to be widely verset in science to know that the higher thu rolling resistance the stronger the pull upon the engine, that the stronger thu pull upon the engine the more gasolin is consumed. and the greater the gaso line consumption--but why continue