Riding-comfort is defined as the transportation of an automobile passenger in so easy a manner that the trip will be a pleasure and not a hardship. Since spring-suspension constitutes the basis of riding comfort in passenger-cars, the paper deals with some of the important factors that determine correct chassis spring-suspension. An analysis made by the National Automobile Chamber of Commerce of replies received to a questionnaire it circulated among 20,000 car-owners is presented in proof of the genuine interest the motoring public has in the riding-quality of a car and the variable factors that have an influence on spring-suspension are stated to be the type of spring used, its physical dimensions, the amounts of sprung and unsprung weight, frame construction, wheelbase dimension and the kind of material used.
Horizontal, vertical and sidewise motions of a car are analyzed, and a periodicity chart is shown for passenger cars of from 112 to 116-in. wheelbase. Since periodicity is a function of deflection, the derivation of the number of vibrations per minute is explained and the reduction of vertical motion is discussed.
A periodicity machine designed to determine the value of interleaf friction as a damping medium is illustrated and described, and the results obtained from tests are stated. Sidewise motion and the effects of balloon tires and four-wheel brakes on riding-quality are treated briefly.