Low Tire Pressure - leak or extreme cold?

Good evening everyone.

For starters, it has been bone chillingly cold the past few weeks here in Michigan - we are talking several days of wind chills taking us as low as 30 below zero. I know this can take a toll on tire pressure, so I have been keeping a pretty vigilant eye on my tires each morning (I know this isn’t proper technique). For the past few weeks, my rear passenger tire has been looking a bit low when it is cold, then looking completely normal when the temps rise again. Tonight when we got home, I noticed that the tire was very visibly low. I busted out the guage for the first time and gave it a look - Ford recommends 30 psi in the back tires, my tire was at 15. Off to the gas station I went to top off. All other tires were at or close to recommended psi. Would extreme cold cause air pressure to drop so radically, or am I potentially looking at a small leak? Car is only driven about twice a week - not sure if infrequent driving could accelerate any issues.

Thanks in advance!

Yes. Cold can have an effect on tire pressure.

But this effect is subtle.

What you’re describing is only one tire is being effected and not the other three. So that indicates there’s a problem with that tire/wheel assembly.

I’d take the vehicle to a tire shop and have them check the tire/wheel for a very small leak by dunking the tire/wheel into a vat of water.


One pound for every ten degrees means that if there were no leaks, the temperature must have dropped 150 degrees. Imo, you have a leak. :wink: And, wind chill has no effect on air pressure. It’s actual temps. Tires have a way of looking low or OK depending on the angle you look at them. Only a gauge tells you for real.

Here’s what Tire Rack says about what you did:

Driving on a tire while flat or with very low inflation pressure will permanently weaken the tire’s internal structure, rendering it more susceptible to catastrophic failure.

You should consider replacing the tire. In the future, as you apparently don’t have TPMS, you should check your tire pressure more often to keep this from happening again.

Thanks for the replies. Leak appears to be very slow - tire shop is about 10 miles away. Is it safe to ride on the tire that far, or should I put the donut on?

I would borrow a pump, manual or electric, and pump it up. Someone must have one hanging around. Pump it up over 35 psi to get you there. If you decide to use the spare, check the pressure before you put it on to make sure it is in workng order.

There is an air pump at the gas station just down the street, and I have a battery powered air pump in my emergency kit, I just want to make sure it will get me there.

You have a leak.

By the way, chill factor has no effect on tire pressure. Chill factor is only a way of describing how quickly an object’s temperature dissipates down to ambient. The temperature never goes below ambient.

Allow me to post an example. If an object is 50F and ambient temperature is 20F, it might take three hours for the object to chill to 20F. However, if there’s wind, it might chill to 20F in two hours, the same amount of time it would take to chill to 20F at 0F without wind. So the ambient temperature is 20F, but the chill factor is 0F.

In short, The object itself will never get below the ambient temperature, it’ll just get there faster with wind… as if it were in a colder ambient temperature without wind.

I personally have never liked the term “chill factor”. It’s unclear. I wish the weather prognosticators would come up with a better term.

With no visible puncture, or object stuck in the tire itself, would this likely be a leak from an issue with the rim?

Wind chill factor is based on how quickly bare skin loses heat depending on the speed of the wind.


Or the valve.
Tire places have tubs to place it into to try to find it. It can also usually be found with a soapy leak-finder that all shops have in a bottle. Note that it’s far, far easier to see a nail with the car on the lift than with the car on the ground, especially if the nail head has worn off.

Regardless of chill, temps have been well below zero the past couple weeks - the wind chill has just made it seem more brutal.

Thank you, same mountainbike. IF the issue were with the rim, is this commonly an issue that would require the rim to be changed out, or is there a cheaper fix? As for the tires, the back tires have been on the car since I bought in in 2012, so they are probably due to be retired soon anyway - looks like I have a reason now. My concern at this point is whether or not I will be able to safely get to the tire center with a slow leak (driving on back roads for the most part - speeds between 45 and 50 mph).

It could be a leak at the tire stem or shrader valve (where you put air in) or the bead where the tire meets the rim, or you could have a small puncture from a nail or other road bebris.

Neither should be an expensive fix. Stop at the station down the road and refill the tire to the right pressure, then drive over to the tire shop. Most are pretty good about fixing a leak without you waiting all day.


Unless you whacked a pothole (?) and damaged the rim, the rim does not need to be changed out. Unless you bought the car used in 2012 and it’s an older car. Alloy rims some years ago had problems with porosity due to corrosion, and that is a possibility. Casting technologies and coatings used now have pretty much eliminated the problem.

The only way to know what the cause of the slow leak is will be for a shop to look at the tire and rim. Hopefully It’ll be a simple nail. However, unless the rim needs changing the fix will be affordable. My own experience has been that it’s usually a nail, easily found with the car on a lift but impossible to find with the wheels on the ground.

Just have it looked at but would be a good idea to put some air in it down the street before driving that far. You could have picked up a little nail, it could be leaking at the bead, the valve core could be leaking, or the valve stem. They’ll take it off and take a look. Don’t think you need to worry about a new tire.

Yep, the tire doesn’t care about wind chill. For some reason this year the weather folks seem to be using wind chill a lot instead of the actual temperatures. People only care about wind chill because it refers to how fast your body will feel the cold. The tires can’t get any colder than the actual temp though even is the wind chill is -30.

“For some reason this year the weather folks seem to be using wind chill a lot instead of the actual temperatures.”

They’re “personalities” now. The more they impress the viewers is the more they end up getting paid. It’s a personality contest. They also dance around with a whole lot of time-filling crap that nobody cares about, even those of us who understand it. Personally, I get my weather from the same place they do; NOAA.

“I get my weather from the same place they do; NOAA.”

Exactly. All of the talking weather manikins are just spitting-out worst-case scenario versions of the information provided (free of charge) to all of us by NOAA. If you use the NOAA website, you can get the information that you need, without the added dramatics and exaggerations.

I Listen To NOAA And Watch TV Weather. Even NOAA Has Drunk The Kool-Aid, Giving Advice On A Recent -27F (actual) Morning, To Be Sure And Wear A Hat And Gloves If Going Outdoors. Duh! My Local TV Weather says To “Bundle Up,” Every Day For Half The Year.

A decades long Famous (Detroit) Michigan Meteorologist didn’t buy into this Wind Chill, Real Feel crap and made it known until his last show. He’s no longer with us.

Experience is the best teacher. Give me the ambient temperature. I already know the winter humidity (dry), and tell me the wind speed. I’m plenty smart enough to know what it will feel like and how to dress. I have to run my snow blower, sometimes at 30+ below and windy.

Another thing… they seem to base wind chill on the highest known gust. That’s irresponsible. Also, wind chill is a measure of freezing EXPOSED FLESH. You should see how much exposed flesh I offer to the wind on those cold mornings.

DUH! The dumbing down of our society is in full force. Cut the drama. Let the dummies freeze a couple of times. They’ll figure it out.

Thanks, I feel better, now.


Wind chill temps are used a lot by the “weather folks” becasue they are as concerned with the people going out into the cold with adaquate skin coverage as they are with regular temps. It is a safety concern and weather people get that. If the wind is blowing 30 mph and the temps are 20 degrees, your car doesn’t care as much as a parent dressing a kid who has to wait at a bus stop for school.

As far as basing windchill on the highest gust, it only takes minutes in sub zero temps and a strung gust to get frosty bite.

In a solid, the surface area varies with the square of the change in the linear measure of the size of the solid. So, kids do very well in cold temps compared to adults as they radiate their body heat much more slowly. What they do not handle well, is wind chill. While small children can survive absolute cold better then adults, they cannot survive windchill much better. That is why it seems unusual for small kids to peal off their clothing, even when it’s cold, as their body heat builds up during exercise. What they don’t get, and parents need constant reminding, is that their exposed skin with a high wind chill can freeze quicker then you would think. Kids suffer from frost bite a lot when people just let them learn on their own. They still need to keep exposed skin covered even if they feel warm.