Just a look won't do it. One of these tires is actually ten pounds under inflated. Your eyes can deceive you, so rely on a good tire gauge for an accurate reading. Look for the manufacturer's recommended air pressure listed on the sticker of you vehicles door jamb or owner's manual. Always check your air pressure to make sure it's up to standards, especially if you're carrying extra weight.
Lower pressure increases heat.
Infrared photography of tires tested at high speed. Damaging heat increases as inflation pressure drops. For maximum mileage, rotate your tires every 5,000 miles. Follow the correct rotation patterns. Tire Wear - Visual Check Check for obvious signs of wear.