Dear My Car Doc,
My tires seem to be low all of a sudden. Did my ex have anything to do with this?
—Restraining Order Next?
As the temperatures have dropped, many of you have probably noticed that the your tires seem to be a bit low lately too. Or, if you have a Tire Pressure Monitoring System (TPMS) that lights up when your tires are low, that light is probably bugging you a lot more lately, right?
So what gives?
It’s science and it’s cool. Here’s the deal: As temperature drops, the air around us condenses a little. We don’t notice it because it’s all around us. However, the air in our tires is trapped in there. (If it’s not, then you have a leaky tire and THAT’S why your tire is low lol.) So what happens when we trap that air and then drop the temperature? Well, the same thing; as it condenses, the air doesn’t fill up as much space as it used to when the temperature was warmer. This makes the pressure in the tire to go down, which makes the tire to be underinflated.
Think about it like this: blow up a balloon, then put it in the freezer. Take it out a day later and what happened to that balloon? It’s much smaller with barely any air in it now (or so it seems). So what happened to the air you put in there? It’s still there, just under a lot less pressure when it’s 20 degrees in that balloon instead of the 98 degree air you blew into it.
So what do we do? That part is pretty simple. Just monitor your tire pressure. Every ten degrees or so, you should recheck your tire pressure and add a little as necessary. This doesn’t mean every time Paul Poteet says we have a cold spell coming you should rush to add air, but take it on average. If it’s in the 40s this week and the 30s next week and the 20s the week after (ugh!), then you should check it out in a week or two to make sure you’re still safe.
And that’s all there is to it, nothing fancy, nothing expensive but something to watch to keep you safe and make sure your four wheeled friends can handle the road they way they’re meant to. This has been another Auto 101 Tip from My Car Doc.