The One Thing Everyone Gets Wrong on Their Car

There's one part of car maintenance that almost no one does correctly, and it's vitally important. Get it wrong, and you'll have an uncomfortable ride that handles poorly and is potentially dangerous -- especially in the rain. Get it right, and you'll have a smooth-sailing dream machine.

I'm talking about tire pressure -- more specifically, how to set it correctly, because chances are you're not doing it right.

You have to measure PSI; never estimate
Aaron Miller/Thrillist

Never just eyeball it

Hey, we've all done it at some point in our lives, but quickly glancing at a tire tells you pretty much nothing about how inflated it is. In the old days it would cue you in you if something was really amiss by the sadly sagging sidewall, but today's modern cars either have very little sidewall (which doesn't deform nearly as much) or they have run-flat tires, which by design have super-strong sidewalls and thus appear normal -- even if they have 0 psi.

Take this tire for example. It's inflated to a woefully low 20 psi, and even upon close inspection by an untrained eye, it looks inflated. Always use a gauge -- a decent one will run you less than $20. Get a good one if you don't already own one.

An under-inflated tire is dangerous in the rain

When a tire is under-inflated, there's not enough air pressure to push the tread out fully against the weight of the car, and it tends to curve inwards. That means you have less tread hitting the ground, which -- among other things -- is outright dangerous if you hit anything larger than a small puddle. The Tire Rack has a great illustration of what I'm talking about.

Your butt will thank you

Your tires are a crucial component of your car for many reasons, but their role of comfort is often overlooked. An under-inflated tire has much less of a spring-like effect -- think of it like dribbling an under-inflated basketball -- so when you drive over a bump, your car has that much less ability to absorb bumps. Once you get the pressure right, your butt will thank you as much as your car.

Setting the right tire pressure is important
Aaron Miller/Thrillist

Use the placard on your car door as a starting point

A lot of people consider the tire pressure numbers on their car door to be gospel. Others don't even even realize there is a placard on the door. Really, those numbers tell you the absolute minimum pressure required, based on a combination of how much weight they'll have to carry (more weight requires more pressure), and how much pressure is needed to ensure all of the tread hits the ground.

Add more air than the recommended minimum

Measure your tires before you drive, when the tires are at their coldest and thus the pressure is at the lowest. Ideally, you should exceed the recommended minimum by several PSI, then drive the car, paying attention to how it feels. Reduce the pressure ever so slightly, and drive it again, repeating until you find your car's sweet spot. Your car will feel more comfortable -- it will better absorb bumps without harshness, and won’t feel overly stiff, either. Even two to three PSI can make a huge difference in both ride comfort and handling, so if you don't believe me, I urge you to try it.

Bonus: use different pressures for front and rear to change your car's handling

If you're on the enthusiast side of things, and you don't already adjust your front and rear tires to different settings, you're missing out. By increasing or decreasing front pressures, you will greatly reduce understeer or oversteer respectively, and the inverse is true for the rear tires. If you don't know what any of that means, stick with what's the most comfortable and enjoy.

Want more of the world's best Cars content delivered straight to your inbox? Click here to sign up for our daily email.

Aaron Miller is the Cars editor for Thrillist, and can be found on Twitter and Facebook. He's considering raising his cold pressure to 40 psi front. Possibly.