What is car tire pressure, and what is the right pressure?

What is tire pressure?

Tire pressure, in short, refers to the pressure of compressed air inside a tire. This pressure greatly affects the performance characteristics of the tire. More specifically, inflating tires to the correct pressure allows the vehicle to roll on the road with the entire tire surface in contact. This ensures even contact, resulting in even tire wear. Furthermore, properly inflated tires offer direct benefits to the user, such as optimal ride comfort, stable cornering, shorter braking distances, and fuel efficiency.

What is the correct tire pressure?

Regularly checking tire pressure is one of the simplest yet most important things to do. Technical experts recommend that vehicle owners perform these checks at least once a month and before long journeys. Incorrect tire pressure can cause many problems; up to 90% of tire failures stem from improper tire pressure.

1. Tire pressure as recommended by the manufacturer.

Typically, information about the recommended tire pressure (as advised by the manufacturer) can be found in the vehicle's owner's manual or on a sticker on the car door. This number is usually expressed in PSI, KPa, or Bar and is often the maximum pressure. These are common units of tire pressure measurement found in owner's manuals or on pressure gauges.

1 Kg/cm2 = 14.2 PSI (Pound per square inch)

1 PSI = 6.895 KPa

1 kPa = 0.01 bar

Each vehicle has a different recommended tire pressure; simply follow those guidelines to adjust your tire pressure for accuracy, safety, and efficiency.

2. The pressure is indicated on the tire sidewall.

As you can see from the image above, the pressure indicated on the tire sidewall is the maximum pressure your tire can withstand. Please note that this is not the optimal pressure for operation.

3. Ideal pressure

The pressure indicated on the car door sill is the manufacturer's recommended pressure. Therefore, the actual tire pressure needs to be adjusted to compensate for the pressure caused by the weight of the cargo/passengers in the vehicle. Generally, reducing the recommended pressure by 10-15% is the optimal level.

It's also important to note that the recommended tire pressure is the pressure when the tires are cold – after the vehicle has been stopped for a long time and the tire surface is not hot.