KEYS, W., "SPRING DESIGN FOR EASY RIDING," SAE Technical Paper 170052, 1917, doi:10.4271/170052.
After pointing out the existing dearth of easily workable data and formulas covering automobile suspensions, the author mentions the elements that contribute to riding comfort. He then outlines what he considers a good suspension, tabulating the spring dimensions of five hypothetical cars, typical of those on the American market. Curves of spring deflection are included in the paper. Functions of rear springs, the damping effect essential in good suspensions, “thin leaf” springs and spring lubrication are next discussed. In conclusion the author covers means of improving a car's riding qualities and cites a very interesting test for determining spring performance by means of the impressions made on a photographic plate by light from electric lamps mounted on wheels and fenders of an automobile and on the passengers.