A difference of 1psi? Irrelevant. Look at it this way…I went and got a haircut this afternoon. Did I lose weight? Certainly. Is that amount something that will be noticeable or affect my health in any way? Nope. Neither will 1psi in a tire.
Now granted there have been posters here that insist that they can feel the difference of 1psi when they are driving. I’m not saying I don’t believe them, but they must have glass butt cheeks to feel it.
Sorry dude both will be at ambient temp, one will not be colder than the other.
I believe the “Gift” and “Snowman” has some tough competition !
It is generally accepted that for every 10 degrees of increase or decrease in temperature, your tires can be expected to increase or decrease by 1-2 pounds of pressure, respectively. This is hardy scientific since there are so many tire sizes and shapes. It is affected by the constructions techniques used on the tires. Some tires are built so sturdily that they have no “stretch”; while some are built with a lot more “flexibility” and they might have some “give ability” or can stretch a bit.
Also, contaminants in the air used to fill your tires affect the rate of pressure change. An air compressor that has not had its tank drained often accumulates water (as in condensation…) in the bottom of the tank and that water is atomized into the air in the tank. Thus, when that air is used to fill up a tire, that tire has some pretty moist air in it and that damp air is more susceptible to pressure changes with the temperature…
Who remembers the little balls of in your tires when it was time to change them? Some folk called them a “Tire’s Dingle Balls,” while others called them “Pearl Balls.” They were caused by the debris from the old tires that mixed with the condensation from the air that on got from the old time gas station air hoses. I guess draining the condensation out of the tanks was not much of a thing back then.
This is one of the selling points of using Nitrogen in your tires verses atmospheric air as the Nitrogen contains no moisture and the Nitrogen molecules are larger thereby less likely to leak out; which has very little validity in fact… Another myth is that Nitrogen is not as affected by temperature, is also a pure myth as atmospheric air is 78% Nitrogen.
This means that two vehicles parked in your driveway and each has different make and models of tires, then if the temperature drops 20-degrees with a cold front coming through during the night, one vehicle’s tires might only drop 2 PSI while the other drops 4 PSI…
So, the bottom line is changes in your tire pressure caused by temperature is more a factor of tire construction and the quality of the air you put in your tires.
Look familiar but never seen them in my tires.
During the summer months I drain the water from the compressor tank daily, however the tank is so hot during the day that the water condenses in the air plumbing inside the shop. Humidity is usually less than 10%. Each day the water accumulation builds up in the pipes, then 8 ounces of water enters my impact gun, this cause rust damage. This is the same air that is used to fill tires.
Some people on this message board despise the use of nitrogen in tires, I use the nitrogen machine when no one is looking. I inflate compact spare tires with nitrogen, those tires have thin sidewalls and generally drop from 60 psi to 20 psi after 3 years, I have no proof of the benefit of nitrogen in a compact spare tire.
Do you inspect the inside of your dismounted tires before they are scrapped?
When I referenced “old time gas stations,” I do it with great affection. In most cases, the stations offered full service, gas, windshield washed, and oil checked. They usually had a Tire Pressure Machine outside, free to use (of course the compressor from the garage provided the Air…), and those compressors probably pumped thousands of cubic feet of air through them every day providing the air for the lifts, air tools, and even those pressure operated bells that rang when you pulled up to a pump… (I’m really aging myself…). And I never knew of a single Old Time Garage that did not provide free tire repair for any child who brought in their bicycle with a flat tire…
And I want to be sure that I am clear, putting Nitrogen in your tires is a Good Thing (even Martha Stewart would agree…). It does not contain any contaminants and no moisture. But saying that Nitrogen is not affected by temperature is a myth. Atmospheric air is affected more only due to the moisture in the air. And to say Nitrogen does not leak out of tires as fast as regular air because the molecules are larger need to have their exhaust systems checked…
Regarding dingleberries: It is my understanding that water has nothing to do with it - that they are the result of debris (sand/dirt) picking up the inside tire lube (necessary to prevent the tire sticking to the curing bladder). That lube is hydrophobic, is not water soluble, and can flake off.
You might see an accumulation of such rubber debris along the sides of NASCAR race tracks.
Yep, except for the pictured tire pressure gauge, our station had a huge compressor that powered everything. Each night, at closing, we shut it down and drained the tank.
As far as the tire pressure gauge, we had the chucks with the slide out pressure reading.
I’m guessing you’re a low mileage driver.
Tires lose air faster when they’re rolling.
I’m driving ~3000 miles a year and rarely have to add air other than in the fall.
I see this effect drastically on my bicycle, which I rode to work daily up until last April.
Now retired and in winter, riding much less, my bike tires lose air roughly 3x slower.
Nitrogen makes up 78 per cent of the air we breathe. so, I do not see that there could be much more benefit in paying for 100 percent Nitrogen to put in your tires.
A 20 degree drop from zero to minus 20 results in a larger change of pressure than a 20 degree drop from 100 to 80. Minus 20 degrees F is 95.6% as hot as zero F, so you will have 95.6% of the tire’s absolute pressure, not gauge pressure. Assuming 14.7 psi barometric pressure, 32psig = 46.7psia. 95.6% of 46.7psia = 44.67, subtract 14.7 to get 29.97 psig.
80F is 96.43% as hot as 100F, this results in the pressure going from 32psig to 30.33 psig. However, on my bicycle it would take the pressure from 100psig to 95.9psig, about twice the pressure loss of a tire inflated to 32psig. So, the rule of thumb formula is only “close enough” for automotive tire pressures and normally found climate temperatures.
With all respect due, weekend, your explanation was just viewed by someone who can barely add & multiply, let alone comprehend what you postulated.
What I did glean from it, and what I know:
Air, as we know it, becomes more dense at lower temperatures. the air at 0degF is more dense than the air at 100degF.
Secondly, the common rule of thumb stated by everyone from the garage down the street, to tire websites, to Consumer Reports, is that cold tire pressure - that pressure before the car is driven - changes “approximately 1psi(6.8kPa) per 10degF(5.5C) change in ambient temperature”. It’s actually about 0.89psi per 10degF, but that’s splitting hairs.
It is ASSUMED that a ten degree F change in temperature, whether that occurs at 30F or 80F, approximates a 1psi change in cold tire pressure.
So given all of that, are you suggesting that the actual pressure loss, given the higher density of air at 0F, is greater if the temperature drops from 0F to -20 than when the temperature drops from 100F to 80F?
IE, using the age-old rule of thumb, 1psi per 10F, results in a 2psi pressure loss from 100 to 80 deg F.
So what, in simple terms for a mathematically-challenged fool like myself, would be the pressure loss, in PSI, for a temperature dip from 0F to -20?
I’ll just add when you put air in, push the valve in for a little puff of air to push out any dirt or water, especially in the winter. Yeah it was cold enough last night to burst my watering wand.
Using the numbers in the @B.L.E post, in a tire at 32psi nominal:
A change from 100F to 80F reduces pressure by 1.67psi
A change from 0F to -20F reduces pressure by 2.03psi
This difference will not be easily seen on any commonly used air gauge for tires.
Plus, the elasticity of rubber at the different temperatures surely has a greater effect.
In other words, it’s academic.
At the limit, dropping temp from -440F to -460F drops pressure 100%…
Thanks for those examples.
It may be “academic”, but I was not aware of it until I read B.L.E.s contribution.
So in the long term, it would be prudent to check cold tire pressures more frequently during the months of October to January, than one would at other times of the year.
Well I’m certainly happy we don’t live on whatever planet such temperatures occur regularly! lol
I have no thermometer that goes to -440 but I have to think checking tire pressure at that temp would not be at the top of my list. Adding more wood to the fire yeah.
I’ll go out on a limb here and suggest the the density of air is not linear with temp, so it may be less at higher temps than lower temps. I really don’t know though and don’t care to learn. I just rarely need to adjust tire pressure in the summer, but do in the winter. I’d suggest a good pair of knee pads though if ya gotta check pressure every couple of days.
Being able to breathe normally, for one, lol!
Bi-weekly tirepressure checks, at most, during the colder months. No need for more.
Back to monthly checks after February.
