JOE WALTER'Modern tires act less like shock absorbers and more like shock transmitters when impacting roadway potholes or speed bumps'

摘要

Since the development of the pneumatic tire,road hazard impacts have caused blow-outs or,if inflation pressure is retained,unseen damage to a tire's internal components.The concealed damage often leads to a flat tire during ensuing motoring.Interestingly,as the overall durability of tires and wheels has improved,some long-term trends have led to adverse outcomes regarding tire and wheel structural integrity.For example,when man first walked on the moon,bias tires and stamped steel wheels were still the norm for North American motorists.Flat tires were more common than damaged wheels.Bent or cracked rims could occur,but were not prevalent.Passenger car tires featured aspect ratios of 78-85% and had rim diameters of 14in or 15in- and operated at a recommended pressure of 24psi.Most wheels were formed of two-piece,pressed steel(the rim and the disc),usually welded together.