Should the inner or outer circle be read on a tire pressure gauge?

[MacJocelyn]

Both the inner and outer circles on a tire pressure gauge can be read, but they represent different units. The outer circle uses the imperial unit psi, while the inner circle uses kg/cm2. The conversion formula between them is 14.5psi=1.02kg/cm2. If the tire pressure gauge reads 2.5, it refers to the black inner circle. Below are factors to consider when adjusting tire pressure: 1. Seasonal factors: In winter, it is advisable to slightly increase the tire pressure by about 0.2bar based on the standard tire pressure. In summer, follow the lower limit of the standard tire pressure. If the car is parked outdoors in summer, the pressure can generally be about 0.1bar lower than the standard to avoid tire blowouts due to high temperatures. 2. Road conditions: On roads with significant bumps, it is appropriate to lower the tire pressure by 0.1-0.2bar from the standard tire pressure. For roads with minor bumps, this can be ignored. For long-distance high-speed driving, the tire pressure should not be too low; it is advisable to slightly increase the tire pressure by about 0.2bar based on the lower limit of the standard tire pressure.

[DeAlex]

I've been using this tire pressure gauge for many years. Generally, the inner scale is in PSI units, while the outer scale is in BAR or KPA. The key isn't whether to read the inner or outer scale, but rather to check if the unit is the one you commonly use. I prefer the inner PSI scale because its unit values are larger, making it clearer and easier to read. If you're driving abroad, the outer BAR scale is more convenient. If the tire pressure is too low, the tires wear out faster and fuel consumption increases; if it's too high, the ride becomes unstable and there's a higher risk of a blowout. It's recommended to check the pressure once a month when the tires are cold, referring to the recommended values on the door label. Don't overlook this small step—it affects both driving safety and tire lifespan. Make it a habit, and you'll save both worry and money.

[DiRosalie]

As a parent who frequently drives with children, checking tire pressure has become part of my daily routine. The inner scale of the tire pressure gauge usually shows PSI, while the outer scale displays BAR. I find the outer scale markings more orderly, so I tend to read the outer scale more often, but I prioritize using whichever scale is more suitable for the unit. Incorrect tire pressure can affect steering wheel feedback, which is especially important when driving on highways. Economically speaking, maintaining proper tire pressure can save about 10% on fuel and extend tire lifespan. During winter when temperature fluctuations are significant, I measure multiple times to confirm. Overall, the key is accurate readings rather than which scale to use. This approach makes driving safer and more efficient.

[OVivian]

When I first started learning to drive, I also struggled with whether to read the inner or outer ring on the tire pressure gauge. The inner ring mostly uses PSI units, while the outer ring more commonly displays BAR. Actually, it's quite simple: just read the scale unit you're more familiar with. I usually use the outer ring because it's easier to read. Tire pressure affects handling, with 30-35 PSI being a common range. It's recommended to measure when the car is cold in the garage for the most accurate reading. If you're unsure at first, just use your phone to convert the units—you'll get the hang of it quickly.