The old saying ?where the rubber meets the road? usually means something will reach a critical point. Naturally the expression refers to automobile tires, since those crucial pieces of rubber are the only part of your car or truck that are supposed to make constant contact with the pavement. That’s why it’s important to know and maintain the correct amount of air pressure in your vehicle’s tires.
To get the right amount, turn not to the tire itself but to your vehicle and a label often located in its doorjamb. That’s where you can find the vehicle manufacturer’s suggested inflation level for your car or truck. If it’s not there, check the owner’s manual. Recently, a reader asked why tire sidewalls often show a pressure rating, shown in maximum pounds per square inch (psi), that differs from the vehicle maker’s recommendation. This may be obvious to racing enthusiasts and mechanics, but not all motorists understand all the nuances. So we turned to some of the experts.
Tiremakers start with a set of standards, set by the Tire and Rim Association (TRA) in the United States and the European Tyre and Rim Technical Organisation (ETRTO) across the pond, and use their guidelines in developing tire sizes’ maximum psi and maximum load levels.
“There’s a load/inflation table for every size of tire in the universe,” said Bob Toth, director of industry relations at Goodyear. But cars and trucks all have varying ...