Substitutes for the conventional type of differential are considered under four classifications; namely, the free-wheel type, the crank and eccentric types, the spiral gear type, and the solid axle. Examples of each of these classifications are described and the advantages and disadvantages of some of the more practical ones discussed.
Considerable space is devoted to a discussion of the elimination of any form of differential whatever. Although such construction has advantages of eliminating the spinning of the wheels and assuring positive travel under all conditions, the author believes the disadvantages too great to be overcome.
The paper mentions some interesting experiments conducted by street railway engineers in connection with using differentials for street cars, to eliminate the corrugation of rails and wheels, as well as to economize in power consumption. It was indicated that with a street car equipped with a differentiating mechanism about one-half the power consumed by a car equipped with solid axles would be saved.
The author believes that the ultimate differential will be one that compensates freely for the difference in speeds of the rear wheels when the car diverges from a straight course, and is so constructed that it will be impossible for either wheel to spin when the other has lost traction.