lizem100, it's next to impossible to 'eyeball'' tires ans determine that the inflation pressure is the same in each. Sure you can notice if one is 10psi lower than the others, but a few psi is not readily apparent. MB and tire manufacturers recommend checking tire pressure with a quality pressure guage at least once per month when the tires are cold, and especially when there's a dramatic temperature change. Every ten degrees difference in ambient temperature can change the tire pressure 1 to 2psi, depending on the volume of air in a given tire.

__________________
Fred Hoelzle