The tire pressure value is calculated by calculating the air pressure injected into the tire space. The common unit of calculation is pounds per square foot (PSI) or BAR.
Generally speaking, the car manufacturer is responsible for calculating and giving the tire pressure that is suitable for your car, and you need to be responsible for checking and supplementing/calibrating it regularly. We recommend checking the tire pressure at least every two weeks.
In the figure above, the left side shows the contact between the tire and the ground under the correct tire pressure. The design of the tire is completely in contact with the ground. At this time, the life and performance of the tire are maximized.
In the middle case where the tire pressure is too high, only the middle part of the contact surface is in contact with the ground (dark color).
On the right is the condition where the tire pressure is too low and only two sides of the contact surface are in contact with the ground (dark color).