Metropolitan-New England Sections Paper - The loss of power due to the friction of the various parts of the chassis has been carefully and elaborately investigated by a dynamometer, the dual purpose being the determination of the amount of internal frictional resistance of the front or rear wheels and the measurement of the power that can be delivered at the rear wheels with the concomitant rate of fuel consumption.
The rolling-friction due to the resistance of the wheels as a whole is taken up first and afterward the separate resistances of the tires, bearings and transmission are studied under varying conditions of inflation-pressure and load. The five frictional resistances that were chosen as giving the most useful information are those of the front tires, the rear tires, the front bearings, the rear bearings and the engine.
Among other topics considered are the ratio of the total friction loss to the weight of the vehicle; a comparison of the resistance of passenger cars and trucks, of solid tires with pneumatic and of fabric tires with cord; the ratio of tire-friction to bearing friction; the rules for determining the total friction of the chassis; the effect of variations in the load and the inflation-pressure on the rolling resistance of pneumatic tires; the development of resistance formulas for fabric and cord tires; a comparison of the wear of pneumatic tires with that of solid tires under the same load; the effects due to variations of the speed and to heavy-wall tubes, roughness of the tread, non-skid surfaces, large and small sizes, age and duration of wear; the development of heat in the tires; and the influence on friction of the rise of temperature of the gearbox lubricant.
The apparent decrease of friction during the last few years and the uniformity of the products of certain manufacturers are noted. The results of the tests are shown in detail by numerous charts and tables.