Is it true that driving with soft tires wastes energy and results in more pollution?
When tires are not inflated to the pounds per square inch (PSI) rating recommended by manufacturers, they are less “round” and require more energy to begin moving and to maintain speed. As such, under-inflated tires do indeed contribute to pollution and increase fuel costs.
Mechanics advise drivers to check their tire pressure monthly, if not more frequently. The correct air pressure for tires that come with new vehicles can be found either in the owner’s manual or inside the driver-side door. Beware, though, that replacement tires may carry a different PSI rating than the originals that came with the car. Most new replacement tires display their PSI rating on their sidewalls.
Also, tire pressure should be checked when tires are cold, as internal pressure increases when the car has been on the road for a while, but then drops when the tires cool back down. It is best to check tire pressure before heading out on the road to avoid inaccurate readings.