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Low Tire Pressures #4540348
10/11/17 02:23 PM
10/11/17 02:23 PM
Joined: Jan 2008
Posts: 10,955
OH
SatinSilver Offline OP
SatinSilver  Offline OP
Joined: Jan 2008
Posts: 10,955
OH
Filled up some newer Nokians to 34 psi a few weeks ago. Someone commented one of the front tires looked low. Checked the tire pressure and it read 28.5 psi. Checked all tires and they all read 28.5 on the digital tire pressure gage. When I filled them to 34 it was after some hwy miles on a hot day. The tires have an "A" temperature rating. Hoping I don't have leaks around the rim. Had them installed at QuickLane who took his time and one of the best according to the advisor.

Re: Low Tire Pressures [Re: SatinSilver] #4540363
10/11/17 02:34 PM
10/11/17 02:34 PM
Joined: Jun 2016
Posts: 3,566
MN
oil_film_movies Offline
oil_film_movies  Offline
Joined: Jun 2016
Posts: 3,566
MN
You lose 1 psi per 10 degrees F due to physics of gases (air). Also, driving around generates heat and pressure too. You put in 34 psi on a hot day after some driving. So attribute about 2 psi to driving around heat generated, and 4 psi due to 40 degrees hotter that hot day, and you just demonstrated physics. Deflategate all over again here.... no scandal.
Knowing that, one can adjust their thinking about tracking pressure.
Also, sometimes its the Schrader valves, not the tires.

Last edited by oil_film_movies; 10/11/17 02:36 PM.
Re: Low Tire Pressures [Re: SatinSilver] #4540366
10/11/17 02:37 PM
10/11/17 02:37 PM
Joined: Jun 2002
Posts: 12,639
The Motor City
Kestas Offline
Kestas  Offline
Joined: Jun 2002
Posts: 12,639
The Motor City
If faulty and leaky, I doubt all four tires would lose air at the same rate.
We've recently had temperature swings going from 80s to 60s.
Also, you mentioned filling them to 34 after hwy driving on a hot day. That'll go down to a lower number in cooler weather.

It's best to check tire pressures in the morning before driving and before the sun warms them.

Re: Low Tire Pressures [Re: oil_film_movies] #4540371
10/11/17 02:41 PM
10/11/17 02:41 PM
Joined: Jan 2008
Posts: 10,955
OH
SatinSilver Offline OP
SatinSilver  Offline OP
Joined: Jan 2008
Posts: 10,955
OH
Thanks, they put in new valve stems when tires were installed. Since all tire pressures were the same I thought that was a good sign. Car is outside all the time and has had a fair amount of hwy miles put on it recently.


Re: Low Tire Pressures [Re: SatinSilver] #4540392
10/11/17 03:02 PM
10/11/17 03:02 PM
Joined: Dec 2003
Posts: 9,918
Florida, Cape Coral
Eddie Offline
Eddie  Offline
Joined: Dec 2003
Posts: 9,918
Florida, Cape Coral
I set my tire pressure before driving in the morning. I use a good gauge. As stated tires increase or decrease in pressure at a rate of ~ one psi for every 10 degree f. change in temperature. Ed


CX5 Touring 2.5L :-)
Re: Low Tire Pressures [Re: SatinSilver] #4540408
10/11/17 03:32 PM
10/11/17 03:32 PM
Joined: Aug 2003
Posts: 13,137
NE,Ohio
Rand Offline
Rand  Offline
Joined: Aug 2003
Posts: 13,137
NE,Ohio
Tires can lose around 1psi a month normally, also 1psi per 10f

my tires were going from 36 to 40 while driving..
well outside temp dropped and suddenly they were at 32-33 36 after extended driving.

Also these firestone destination AT seem to lose abit more air than other tires I've had previously.

If its the 2005 with alum wheels.. they can lose quite abit of air from bead seat corrosion.. but all of them dropping the same makes that unlikely.


2019 Jeep Cherokee Trailhawk 2.0T
Re: Low Tire Pressures [Re: SatinSilver] #4540413
10/11/17 03:44 PM
10/11/17 03:44 PM
Joined: Apr 2016
Posts: 1,198
Campbellsville, KY
Alex_V Offline
Alex_V  Offline
Joined: Apr 2016
Posts: 1,198
Campbellsville, KY
Keep in mind that the sidewall rating is "COLD" so even at what most refer to as "max sidewall" it's still designed for expansion. I usually only see about 3 PSI swing on my Cruze's TPMS from morning/cold to the peak of a mid-day highway run, but that they all dropped consistently sounds much more like expansion/contraction than leakage.


To quote a friend, "Synthetics, man."

'85 GMC C3500, 454, 132K
'82 Mercedes 300CD, OM617 turbo, 173K (totaled 2018, in rehab)
'85 Mercedes 300TD, OM617 turbo, 217K (wife's)
'67 Suburban, 350, 331K
Re: Low Tire Pressures [Re: SatinSilver] #4540460
10/11/17 04:47 PM
10/11/17 04:47 PM
Joined: Jan 2007
Posts: 17,501
Clovis, CA
Merkava_4 Offline
Merkava_4  Offline
Joined: Jan 2007
Posts: 17,501
Clovis, CA
Originally Posted By: SatinSilver
When I filled them to 34 it was after some hwy miles on a hot day.


That's it right there.

Re: Low Tire Pressures [Re: Merkava_4] #4540490
10/11/17 05:25 PM
10/11/17 05:25 PM
Joined: Feb 2013
Posts: 425
Nevada, USA
gaijinnv Offline
gaijinnv  Offline
Joined: Feb 2013
Posts: 425
Nevada, USA
Here's a page from a Toyota TSB you might find helpful:



HTH


USN NAVSECGRU 1970-1974
Re: Low Tire Pressures [Re: SatinSilver] #4540687
10/11/17 08:09 PM
10/11/17 08:09 PM
Joined: Jun 2016
Posts: 3,566
MN
oil_film_movies Offline
oil_film_movies  Offline
Joined: Jun 2016
Posts: 3,566
MN
gaiginnv, I've never seen a chart like that. Kudos to Toyota. However, its too complicated for the average John Q. Public out there.
Its even able to fool us because the "O deg F" shown on the left vertical axis is really the DIFFERENCE between room temperature and the ambient outdoor temperature you are checking the tire at, NOT 0 deg F winter temperature.
Want it complicated a bit more(?): A tire parked in shade vs. a tire in full sunlight will read about a couple of psi different.

In summary: The B-pillar placard temperature is really the 70 deg F pressure. Now add or subtract 1 psi for how hotter or colder the ambient air temperature is, and put the tire in the shade (no sun), and let the tire cool for at least a couple of hours after driving. Still too much for people to follow. Soccer moms don't want any of this.

Re: Low Tire Pressures [Re: oil_film_movies] #4540804
10/11/17 11:17 PM
10/11/17 11:17 PM
Joined: Feb 2013
Posts: 425
Nevada, USA
gaijinnv Offline
gaijinnv  Offline
Joined: Feb 2013
Posts: 425
Nevada, USA
Originally Posted By: oil_film_movies
gaiginnv, I've never seen a chart like that. Kudos to Toyota. However, its too complicated for the average John Q. Public out there.
Its even able to fool us because the "O deg F" shown on the left vertical axis is really the DIFFERENCE between room temperature and the ambient outdoor temperature you are checking the tire at, NOT 0 deg F winter temperature.
Want it complicated a bit more(?): A tire parked in shade vs. a tire in full sunlight will read about a couple of psi different.

In summary: The B-pillar placard temperature is really the 70 deg F pressure. Now add or subtract 1 psi for how hotter or colder the ambient air temperature is, and put the tire in the shade (no sun), and let the tire cool for at least a couple of hours after driving. Still too much for people to follow. Soccer moms don't want any of this.


Just about all of that is incorrect spank


USN NAVSECGRU 1970-1974
Re: Low Tire Pressures [Re: SatinSilver] #4540815
10/12/17 12:04 AM
10/12/17 12:04 AM
Joined: Feb 2013
Posts: 11,077
Phoenix, AZ
Nick1994 Offline
Nick1994  Offline
Joined: Feb 2013
Posts: 11,077
Phoenix, AZ
Same thing recently happened to me. The Sonata's tires were around 29 psi which I usually keep at 36. But my Jeep's tires were still at 35 psi shrug but it sleeps in the garage all the time.


2015 Hyundai Sonata 2.4L 88k Motorcraft Synthetic Blend 5w30 & OEM
2000 Toyota Camry 2.2L 231k Valvoline 5w30 & Fram Ultra
1996 Jeep Cherokee 4.0L 147k Mobil 1 HM 10w40 & Fram Ultra
Re: Low Tire Pressures [Re: Nick1994] #4540849
10/12/17 03:55 AM
10/12/17 03:55 AM
Joined: Jan 2016
Posts: 707
Nebraska
Duffyjr Offline
Duffyjr  Offline
Joined: Jan 2016
Posts: 707
Nebraska
Right after I put some Cooper's on my Buick they were losing 2-4 pounds every 3 or 4 weeks which I thought was a little excessive but after a while this stopped. Now I only need to adjust them 3 or 4 times a year. I'm not sure what happened here but I'm guessing they sealed better or settled on to the rims over time due to the rims being old or dirty.


89 GMC Sierra VWB 5w30/TG3980
08 Lucerne CX Magnatec 5w30/TG3387A
02 DeVille VWB 5w30/CQ Blue
18 Toro Super Recycler T5 10w30
Re: Low Tire Pressures [Re: gaijinnv] #4541070
10/12/17 09:23 AM
10/12/17 09:23 AM
Joined: Jun 2016
Posts: 3,566
MN
oil_film_movies Offline
oil_film_movies  Offline
Joined: Jun 2016
Posts: 3,566
MN
Originally Posted By: gaijinnv
Just about all of that is incorrect spank
If you still disagree with Toyota, then I suggest you go back and study engineering. The Toyota chart is correct. What parts of it are you not understanding?

Re: Low Tire Pressures [Re: oil_film_movies] #4541239
10/12/17 01:03 PM
10/12/17 01:03 PM
Joined: Jan 2008
Posts: 10,955
OH
SatinSilver Offline OP
SatinSilver  Offline OP
Joined: Jan 2008
Posts: 10,955
OH
Thank you everyone for the comments. Some very good points were made. Checked the psi this morning of just one rear tire and it was 34.5. When I filled all the tires yesterday to 35 they were warm from getting off the highway, maybe 10 miles. Temp yesterday was in the low 70's. I only checked one tire this morning since I didn't feel like checking all of them. I will check them again next week.

My mom commented the other week the front tire looked low. Which is why I checked it. When I saw 28 psi I thought for sure I'd be taking it in for a leak repair at Discount Tire. But when all of them had the same psi I knew that probably wasn't the case.

A week or two ago we saw some temps in high 30's and some highs in upper 80's. Plus a fair amount of hwy driving. Probably about 2000 during the last air fill up.

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