Mikes01pet

This is driving me crazy every tire has a different reading I know the front and the back can be different but every single Tire everyday has a different reading even if I go to the garage and have them put the pressure in 2 hours later or the next day every tire is different is this normal please help thanks

Lexuss07

You are supposed to check the tires for air pressure, cold, and first thing in the morning. That is what I do. I take a digital gauge ( and compare it with tire pressure readings in the car, and they are consistent with one another) use their air tower, if needed. It is normal for the tire pressures to fluctuate after you have been driving.

Poppa

Yes, as Lexuss07 said, check your air pressure when your tires are cold.. and as you're driving and your tires heat begin to heat up, the air pressure in the tires will increase a little also.

ESully

Tire pressure can be a bit of an art to get right. The sticker shows recommended cold pressure, so adding a few pounds more if the car has been driven a bit when you stop to add air is a good idea, it will drop when the car sits and tires cool.
My tires will go up from cold in the morning about 4 or so pounds after a bit of driving. It will even go up a bit depending on whether the sun is shining on a tire more than others.
I spend quite a bit of time at my friends shop. He always expects a lot of visits for TPMS lights when the seasons change. When he does oil changes, he tops up all fluids and sets tire pressures. If one or more tires is quite a bit off from the others, a quick check is done for nails.
Some customers complain that a certain tire seems to lose air slowly. I've spent a bit of time at the water tub after removing a tire to find slow leaks. Sometimes it can take awhile to find that occasional bubble. Often slow leaks are due to a tire valve leaking, or on older cars the rim leaks from oxidation on older cast rims. I've had 2 tires on my '05 Corolla go flat from the rubber valve stems cracking from age and leaking. I put all new valve stems in the car, which was cheap since they did not have TPMS. There are repair kits with new seals for the TPMS valves also.

Poppa

One thing that I've found to keep the tire pressure from fluctuating so much in extreme temperature changes is to use nitrogen to fill the tires. My last two sets of tires were filled with nitrogen and I don't think I've seen more than 1 lb of fluctuation in the air pressure since. I've seen this posted before, and debated before. I know nothing about the chemical properties of nitrogen. But I know for a fact that when my tires were filled with nitrogen the air pressure stayed constant ( within a lb ) whereas before, if the temperature dropped 30 degree's over night, the air pressure in my tires did as well.

Roland

Freds430

This does not address the fluctuation but you in CT the weather is cold. For every ten degrees colder one loses one pound of pressure. If in September it was 80 degrees and now 40 you have lost 4 pounds.

Tootsall

The thing to remember is if you set tire pressures at 33 psi and, say, 50 deg temp, then park your car outside when the temperature drops to 10 (or even lower...-20 and-30 are experienced occaisionally here), you are going to lose ~4 psi and that could be enough to trip your low pressure alarm. I usually reset my tpms with the pressures at around 30 psi, then bring pressures back up to 33-34 just to avoid that nuisance alarm.

Poppa, atmospheric air is 78% nitrogen.

jamestpc

are you storing a summer set of rims/tires/TPMS sensors in the garage too? Those could play havoc with your readings until you've driven away, hence the varying pressures.

Just a thought.

Tootsall

I do store the second set in the garage within about 6’ of the car. I find that the oem sensors on the car are not affected at all by the stored Autel after-market set but when the wheels with the Autels are mounted they wait until I’ve driven out of the garage to display a reading. Even then the readings are consistent when they come up. As pointed out, there will always be variations of a pound or two and the best policy is to switch the multi-function to display to anything other than tire pressure. Pressures are going to vary so no point in obsessing over it.

Mikes01pet

tire pressure, i appreciate all the responses and understand the facts ,but still , the question ,each tire has a different reading, i had big tire place tell me u had a slow leak in valve, so they replaced it, it still leaks if that was the real problem ( ?). Di i need to change the tpms, been told you can't change just one, and told yiu can change just one.so???, changing 4 is over $400.00 - $500.00.

Tootsall

Even the pressures up and watch them for a few days. Unlikely that a sensor is off...if the battery is fading that one will just stop transmitting and you’ll get a system alert. Confirm pressures with a manual guage. Then get them all changed when you switch tires. Otherwise if one keeps dropping more than others start looking for a leaker. See ESully’s response above.

Mikes01pet

This all started after i got new tires in feb 2020, i have had the garage set the pressure multiple times, as i keep going back to them ,and i do watch and in 2 hrs or a couple of days they all start changing again, thats why it drives me crazy. I always get an alert on the tire with the lowest pressure , generally thats at 29, sometimes at 30.

Mikes01pet

tire pressure .... no havent bought winter tires yet, not alot of snow last year, i think your right in turning that display off, thank you

ESully

I really doubt it is the sensors in the tires. I have never seen that as an issue in my friends service station. I would believe it is a slow leak. As i mentioned in my previous post, finding slow leaks can be a very tedious process, and most will not want to spend the time it takes to track it down. A very slow leak will not be found unless the tire is submerged in a water tank with a lot of patience tracking down that small occasional air bubble .
Only turn on your tire pressure display first thing in the morning. The only accurate check of tire pressure is when they are cold in the morning without the sun shining on them. Once you are on the road, tires will have slightly different temperatures, whether from heat from rolling, cornering where more load is put on one side, stress from acceleration and braking, sun warming one side more than others, etc.

st1800

“The only accurate check of tire pressure is when they are cold in the morning without the sun shining on them”

Driving around getting the pressures checked by someone else, won’t get you anything accurate.

first thing in the morning, no sun on the tires, check the pressure. And adjust them. Otherwise it “ will drive you crazy”.