Tire pressure - do we, or don't we?

[NutmegCT]

As temps drop here in Connecticut (this morning, 8 degrees), my 2020 Altima tire pressure warning pops up.

Tires should be 33 psi; after all night in the cold, tires are 26 or 27. Pressure increases during driving, up to 30 within an hour, but never up to 33.

Am I slowly causing damage to the tires by driving four months of 30 days each (120 hours) on those low pressure tires before they warm up?

Should I add pressure to bring the tire up to 30 *after sitting all night in the cold*?

What to do, what to do ...

Thanks.
Tom M.

 

[LarryK]

Tires should be. Checked weekly, especially when up and down temps abound. Check when cold, set to 33. They will come up some, but the.factory says 33 cold. You'll add in cold and sometimes let off when warm. If you are a competition driver, we always add a couple pounds. My MINIs have a cold pressure, a load pressure and a sustained speed pressure. Sustained 100 mph speed pressure would be for the Autobahn for example. Just follow door tag and check at least monthly. I personally check my 35 tires at least every two weeks. Helps if you have compressor at home.

 

[NutmegCT]

Thanks Larry. So you're saying I should inflate tires to 33 psi when cold in the morning, even tho' driving will increase the pressure to over 33?

Just want to be sure I understand.
Tom M.

 

[LarryK]

You have a set cold and this does compensate for the rolling resistance heat build up. Only racers work with the temperatures for grip and controlled drifts. In Solo, we check for temps after each run for setup of suspensionas you try to equalize all four corners. For daily driving, just follow factory settings from cold. Now, if you are an 80 mph driver, you might raise cold temp 2 lbs. all around. This is what gets scary on I terstates with these 100mph drivers, did they check their pressures before the speeds and are their tires rated for the speed with the weight of their vehicle. Truckers have to check their tires at every stop because of weight. Also, pay attention to the dates on the tire, replace 5-7 yrs.

 

[DrEntropy]

This is what gets scary on I terstates with these 100mph drivers, did they check their pressures before the speeds and are their tires rated for the speed with the weight of their vehicle.

Gotta wonder how many of the Ford Explorer rollovers were due to inattentive owners neglecting to check their tire pressures... :eeek:

 

[Madflyer]

The Ford Explorer is a good example of tire neglecting Ford was in bed with Firestone and the tire only met the min for safety neglecting is what killed people.. Racer have tires down to a science. If your are not that person under inflated tires are where tires get the most damage. If the car maker says 33# cold is that room temp, outside temp, inflated on the car off the car. When you buy a new set of tires ( that is all four ) the installer fill them off the car. A over inflated tire has less foot print and less heat build up. A pond or more over will keep the sensors from going off when winter comes. As stated above tires are dated that 6 year old can not repaired in most states. If you are in a high temp state and or park in the sun all the time it is the sidewall not the tread depth to the DOT that what takes the life of tires. Trailers tires are the worse for neglecting. Any tire is cheep life is priceless. Madflyer

 

[Gliderman8]

Gotta wonder how many of the Ford Explorer rollovers were due to inattentive owners neglecting to check their tire pressures... :eeek:[/COLOR]

I always checked my tire pressure but I still had a blowout going 65 mph on the PA Turnpike. The back end of my Explorer was fishtailing all over the road. I had all I could do to get it stopped with wheels on the pavement.

 

[DrEntropy]

I've no doubt of the collusion between Ford and Firestone to fit the vehicles with tires of minimum cost vs. safety standards, Elliot. Just wondering about neglect exacerbating the issue.

 

[Gliderman8]

I've no doubt of the collusion between Ford and Firestone to fit the vehicles with tires of minimum cost vs. safety standards, Elliot. Just wondering about neglect exacerbating the issue.

No doubt you are right about cheap tires. When I went to get them replaced at a Firestone dealer they only wanted to give me 4 tires. I would not stand for that and in the end I got the spare replaced as well.

 

[LarryK]

I like how the dealers, car and tire, push nitrogen. I heard one guy say you never have to check tire pressures. I let him have it. Nitrogen is more expensive an doesn't expand to climate as air with moisture. So, if you don't check your tire and have a leakdown, what are you going to do? Everybody hits the now $1.00 air pump at the closest station. OK now, you don't have nitrogen but that cusstomer thinks he/she is protected. In racing, yes, the nitrogen tire is more stable. But, what is the guy behind the wall doing with the pressure gauge when the tire cools, checking pressure and getting the last lap tires ready. When I worked at a shop, a lot of the problems were the customer not even walking around their car before travelling to see if the tires are up. Then, there is the cheap guy who buys 4 c rated treadwear tires with a barely minimum weight for the vehicle who travels 100mph to work and back. Can't educate them, can't fix stupid.

 

[John Turney]

I understand that when they say "cold", that means 68F (20C). Our Subaru manual has temperature corrections for tire pressure.

 

[elrey]

Now if the surrounding atmosphere is already 78% nitrogen and 21% oxygen and the claim is that the smaller oxygen molecules leak out first, after refilling your tires a few times with atmospheric air over time shouldn’t one end up with a healthy nitrogen content?
And secondly, when they mount your tires, I do not believe they collapse them with a vacuum as to remove all the atmospheric air, so I wonder what the heck, is it worth the trouble for the avg. shmoe to bother at all?

 

[elrey]

 

[LarryK]

Cold always meant ( as stated in service manuals back to the 40s ) sitting still not moved for 4-6 hours. Typically, first thing on a Sat. morning before mowing the lawn. Typical non-automotive driver does not need nitrogen. For a while there it was another status symbol.

 

[maynard]

Most important is to replace the summer air with winter air.

 

[Basil]

You have a set cold and this does compensate for the rolling resistance heat build up. Only racers work with the temperatures for grip and controlled drifts. In Solo, we check for temps after each run for setup of suspensionas you try to equalize all four corners. For daily driving, just follow factory settings from cold. Now, if you are an 80 mph driver, you might raise cold temp 2 lbs. all around. This is what gets scary on I terstates with these 100mph drivers, did they check their pressures before the speeds and are their tires rated for the speed with the weight of their vehicle. Truckers have to check their tires at every stop because of weight. Also, pay attention to the dates on the tire, replace 5-7 yrs.

My onboard TPMS tells me the pressure. If we have a cold snap in the morning but I expect warmer temps later in day, I will sometimes top off the tires but leave them about 2lbs low on purpose, knowing the "cold" pressure will increase as temps increase. If the temps are reasonably warm outside when I top up, I'll just top up to the recommended "cold" pressure. I used to get the low pressure warning on my Santa Fe (18" tires) all the time on very cold mornings, but so far have not had that happed in the Kia (20" tires). Not sure if having the lower profile tires on the Kia has anything to do with it.

 

[pdplot]

Very pertinent. My low tire pressure icon lit up a couple of days ago on the Subaru. I checked the pressures. Between 20 and 23 lbs. Supposed to be 32 and 33. I filled the tires to 32, drove the car over 20 mph and the light went out. There's also an icon that lights up when the temperature is below freezing. It's been on for 3 days.

 

[Madflyer]

Basil You have a good point large rim size may not make for more air with low profile tires. If it were oil we could say add a Qt. in winter but compressed air what volume are we looking at. Should we also question sea level. When adding air in winter that contains moisture. Many years ago working at a Shell station in Sacramento Ca. it was not uncommon to fine water inside tires. Would that not go to steam in the Sacto summers. Maynard do you have a point. People have died because of Firestone and the Explorer, and was not the first time Remember the Firestone 500. I know cars are not airplanes and we do not preflight.

Tom has a good question so Tom I hope you find your best guess I do not know if many of these Threads helped you. Madflyer

 

[70herald]

I remember reading about Sir Stirling Moss requesting adjustments of his tire air pressure in 1/4 psi increments!

 

[vette]

As temps drop here in Connecticut (this morning, 8 degrees), my 2020 Altima tire pressure warning pops up.
Tires should be 33 psi; after all night in the cold, tires are 26 or 27. Pressure increases during driving, up to 30 within an hour, but never up to 33.Thanks. Tom M.

It's not uncommon for tires to loose air while sitting during a "cold Snap" If the air has gone out of them then the air needs to be replaced. Of course air pressure in a tire will increase as the tire is heated up during running but it will not recover lost air. Typically tires will increase from 3 to 5 lbs air pressure from a cold sitting state to a warm highway state. As stated above cold state is usually described as after the tires have sit still for 3 to five hours. So if you believe your tires have lost air then give it a rest and set the tire pressures uniformly with consideration of the pressure stated on the side of the tire. You want the pressures to be nominally what is stated on the side of the tire.
If you spend a lot of time at highway speeds then set the tire pressure when they are cold at a few pounds less than what is stated on the side of the tire. That way when you are at speed the pressures will have increased some and they will be approximately what is stated on the tire.
If you spend more time in slower, stop and go traffic then just set the pressure when cold at what is stated on the tire. Even tho you might get to highway speeds the small difference in temp for the tire will have the tire pressures within range.
Here's a short story as an example: A year ago I drove my C5 Corvette on a loop around the USA. The car was perfect with do mechanical or ergonomic problems what so ever. But I had one issue that took awhile for me to resolve. That was tire pressure. We went in late August and I considered what to set my tire pressure at before I left seeing as how we would be traveling at high speeds in some of the hottest parts of the country. Now I had spent time in Florida many times with the car, had typically set my tire pressure at 33psi and never had any problems. But during this trip across country I monitored my tire pressures regularly. I was running about 38 to 39 psi and was comfortable with that. After getting to Omaha and starting to see 80 mph speed limits, naturally I was cruising at a pretty good rate of speed. My tire pressures started to creep up. I was remembering that my tire high pressure alarm was at 40psi and decided to rely on that when I should stop to make an adjustment. Well as time went on I never got the alarm. I checked the readout and the pressures were well above 40 psi. I said to the wife, if they hit 42 I'm pulling over. Well they did and then the High Pressure alarm went off. So my memory wasn't as good as I thought. So I pulled off and took some air out. The next morning at the motel near Mount Rushmore, my tire pressures were at 27 psi. The combination of them cooling off and my taking too much out the day before had them much lower than I wanted them. So I got to a station and put some back in. They were fine for a few days till we headed to Utah. I wasn't very accurate when filling them back at Rushmore so when I got to Moab I pulled into a Chevy dealer to get an oil change and asked them to balance my tires. When I was leaving Moab the ambient air temps had reached 101 degrees. I noticed that the Chevy dealer had set my tire pressures at 35 psi. I thought well I don't think this is going to work, sure enough I wasn't on the road for an hour and my alarm went off. I pulled into a truck stop and lowered my tire pressures as carefully as I could and set them at 36 psi hot. I didn't have any trouble the rest of the trip. But the tires pressures were the only fussing I had to do with the car on the whole trip.