Should You Underinflate Your Tires in Winter?

By: Jamie Page Deaton  | 
tire in snow
Underinflating your car's tires can give you more traction on snowy roads; but is this a solid strategy, or a tip you can skip? Massimo Calmonte/Getty Images

Snow tires, all-wheel drive, four-wheel drive, bags of kitty litter in the trunk — people will do just about anything to gain an edge when driving in snowy, icy winter weather. For the most part, these strategies are good ideas. After all, winter-slick roads raise the risk of having an accident, and the best way to survive a car accident is to prevent one from happening in the first place. One winter driving trick that some people swear by is underinflating their tires.

To understand why some people think underinflating tires in winter is a good idea, you need to know what's happening when your car goes into a skid (besides everyone in the car freaking out). No matter what the time of year, your car needs traction to stay on the road. Traction is the friction between two surfaces — in the case of a car, it's the friction between the car's tires and the road. That friction allows the tires to grip the road surface and not slide all over the place. The more traction you have, the better control you have. One of the key factors in traction is the tire's contact patch, or the amount of tire that's physically touching the road. The bigger the contact patch, the more traction.


That's what underinflation aficionados are thinking about when they let some of the air out of their tires in winter. When you underinflate a tire, it droops, letting more of the tire touch the road. In certain cases — like driving in some snowy conditions and on sand — underinflating your tires is a great tactic.

There is, however, a rub when it comes to underinflating winter tires, and it goes back to that enlarged contact patch. Extra traction is a good thing when you're driving in the snow, but it becomes a not-so-good thing once the roads are plowed. Underinflated tires will give you (believe-it-or-not) too much traction, which will lead to difficult steering — and a car you can't steer well, obviously, isn't all that safe. Also, depending on the depth of the snow you're driving in, properly inflated tires can sometimes more easily dig through the snow to the pavement below, whereas the wider underinflated tires will ride only on the surface of the snow. Finally, underinflation damages your tires and wheels.

So, underinflating your tires is one winter driving tip that you can definitely skip. Now, keeping a few dozen pounds of kitty litter in your trunk is another story. Not only is it handy when your car gets stuck in the snow, but you'll also have a ready-made litter box for all the neighborhood felines when spring finally arrives.


Winter Tire Pressure FAQ

What should my tire pressure be in the winter?
The tire pressure of a car should be between 30 and 35 PSI. Anything less will impact the fuel economy of the vehicle and will make it more difficult to drive.
Should I inflate my tires in cold weather?
Yes, it is recommended to check and inflate tires more frequently during cold weather. Low tire pressure can make it more difficult to drive, which is more dangerous when there is snow or ice on the roads. The ideal pressure of the tires during winter should be indicated by the manufacturer.
At what temperature should I check my tire pressure?
Tire manufacturers recommend that you check the pressure of your tires if the daytime temperature is around 70 degrees Fahrenheit and nighttime temperature is around 20 degrees.
How do you adjust tire pressure in the winter?
Find the recommended tire PSI in the owner's manual of your vehicle. It will also be indicated in the sticker in the car door jamb. Check the pressure using a pressure gauge by unscrewing the valve stem cap of the tire and attaching the tire pressure gauge. Replace the valve stem cap or inflate the tires immediately, if required.
What PSI is best for tires?
PSI stands for pounds per square inch and is used to measure the air pressure in a tire. It is normally recommended to keep the pressure around 30 to 35 PSI, but this may vary depending on the temperature outside and the particular tire.

Lots More Information

Related Articles

  • Connecticut Department of Transportation. "How to Deal with Ice and Snow!" State of Connecticut. (April 24, 2015)
  • Magliozzi, Tom and Ray. "Car Talk: What's the proper tire pressure on snow, ice? Loser cooks." Seattle Post-Intelligencer. May 4, 2006. (April 24, 2015)
  • Rubber Manufacturers Association. "Winter Driving Tips." (April 24, 2015)