Today I disassembled 4 alloy wheels from a 2010 Prius I purchased from a family member. The goal of the effort was to polish and seal the valve stems holes. I've noticed that even slightly corroded valve stem holes cause slow leaks. Tire shops refuse to deal with these leaks, simply saying "You need new alloy rims that will cost more than the car is worth." Or they try to blame the rubber grommet around the valve stem, not realizing that I pre-equipped the stem with a new one. Before disposing of today's entirely worn out tires I cut them up to transport them to our city's recycling center. Two of the tires were expensive Goodyear Assurance tires with high wear ratings. The other two were cheap "lick and a promise" tires from Asia with poor tire wear ratings. I tried to fold the tread portions of the tires and tightly bind them with zip ties. The Goodyear Assurance treads were much more pliable than the Asian treads. It took almost all my strength to fold the Asian treads. The Asian tires were also about 20% heavier than the Assurances. Is there a logical connection between light and pliable tires and high wear ratings? Why would an Asian vendor selling bargain basement tires ship heavier and stiffer ones?
Probably because they are using cheaper rubber compounds and fewer performance additives. The tires need to stay flexible in order to create better grip. The grip itself is caused by the tire's ability to be squeezed into the tiny cracks in the road surface. My bet is that if you put the cheap Chinese tires on a car and put the Goodyears on another, even at the same high mileage, the Goodyears would provide much more grip on a skidpad. (Hence why I always recommend against mixing tires, because if the tires on the front are much stickier than the ones in the back, then you can possibly create an unstable oversteer condition that you probably won't know about until your first avoidance maneuver.)
