Want better handling? Longer tire life? Maximum grip in a panic stop? It all starts with the right air pressure in your tires. That’s usually measured in pounds per square inch (PSI). But tire PSI is more than just numbers on your doorsill sticker. Your ideal tire pressure depends on road conditions, temperature, and even driving style. Here’s everything you need to know to dial it in like a pro.

What happens if tire pressure is too high?

Overinflated tires wear out fast—first at the center of the tread, then everywhere else. But that’s the least of your worries. With less rubber touching the road, traction suffers. Braking takes longer, acceleration is weaker, and cornering gets sketchy. Discount Tire warns, “Overinflation causes a harsh ride, poor handling, and irregular wear.”

Why does this happen? Picture a basketball. Pumped up hard, it bounces easily. Let a little air out, and it absorbs impacts better. Tires work the same way. Too much pressure and they become stiff, reducing grip when you need it most.

Some drivers overinflate their tire PSI, hoping to boost fuel economy. MythBusters found this doesn’t even work. And the trade-off in safety and longevity isn’t worth it. Stick to the manufacturer’s recommendation for even wear and maximum traction.

What tire PSI is too low to drive on?

How low is too low? A general rule: anything under 20 PSI is dangerous, and below 15 PSI, you’re rolling the dice. But the risk depends on the vehicle, tire type, and speed. Heavier cars and softer sidewalls make things worse.

Too little air? Big problems. Underinflated tires wear unevenly, overheating and stressing the sidewalls. Discount Tire explains, “Routine stresses, environmental factors, and impacts from driving conditions can reduce tire air pressure.” If you drive long enough on low tire PSI, you could have a blowout.

The bottom line? If your tires look low, they probably are. Check them regularly—especially in cold weather. Tire pressure drops by 1 PSI for every 10-degree temperature drop, so don’t assume yesterday’s reading is good today.

What is the best tire pressure?

Short answer? Check the sticker inside your driver’s door. It lists the PSI your tires should be at when cold. Most passenger cars sit between 30-35 PSI, but SUVs, trucks, and performance cars vary. Unless you’re running drastically different tires than stock—like mud-terrain or ultra-low-profile performance tires—stick to what’s recommended.

For more precision, consider the temperature factor. As Firestone explains, air pressure rises about 1 PSI for every 10-degree increase in temperature. That’s why your tires read higher in the afternoon than in the morning. Always check PSI before driving for the most accurate reading.

Want to fine-tune PSI for driving style? Performance enthusiasts sometimes adjust tire pressure for better grip. The 10/20 method—used by motorcyclists—suggests a warm tire should gain 10% PSI in the front and 20% PSI in the rear after the average drive. This ensures optimal flex and traction.

The takeaway? Keep an eye on PSI, check it monthly, and adjust for extreme conditions. Your tires, performance, and wallet, will thank you.