New 4Runner Owner - Tire Pressure Question

Too funny…. I was thinking the same thing. Even my good one is made in China…. But I still know what he means by the cheap “Chinese” pieces of crap.

 

Mine is (at least) 15yrs old, back then it was made in the US.
Your info is incorrect as it is NOT discontinued, it is still being produced, just in China now.
They were the “go to” gauge in NASCAR back then. You could throw it against the floor and it wouldn’t break it.

 

Just razzing you. It is extremely difficult to find an actual USA or Germany made inflator. I have a cheap Canadian Tire (Canada's Habor Freight) gauge that works surprisingly well.

 

Interesting. So what you’re implying is that if I am parked facing north in a parking lot with a clear view of the sky all around, if I check the TPWS in the morning, the tires on the passenger side will have a higher pressure than the tires on the driver’s side? And then if I return later in the afternoon, with the sun in the western sky, and check the TPWS again the tires on the driver’s side will have a higher pressure?

 

I cannot see the sun exposure generating enough internal heat to increase the tire pressure.

 

Me neither.

 

Good for a couple psi between the sun side and the shade side, especially if it has sat for a couple hours like that in the bright sun. Black rubber absorbs light/heat quite well.
Edit. When air increases in temperature it expands.
Note your pressure in the shade then park one side squared to the afternoon sun for an hour and you will see a difference.
2nd edit.
The tire has be an ambient temperature. The colder the outside temperature and the brighter the sun will make the biggest difference.

 

Here is one for you. You buy a new set of tires and to eliminate moisture inside the tire (which is what expands causing the pressure fluctuation when the tire heats up) you pay the extra for nitrogen. But when the guy is installing the tires you notice how much soapy water lubricant he sloshing inside your tire trying to get the rims on.

 

I wanted to sweep the garage anyway so I just backed it out 30’ for the sun to hit it on the passenger side. The results would be better but we have thunder clouds moving in. Rain is coming and I just washed it yesterday…end of test.

2:35 PST in the garage

2:50 PST

3:05 PST

 

It absolutely does, especially here in the desert. I see it all the time. Not by much but I've seen up to 3 psi difference in the tires facing the sun versus the tires in the shade.

 

Thanks for that empirical test. Always appreciated even if it proves me wrong.

 

Us AG ORP gotta stick together…..

 

I have Nitto Ridge Grapplers 285/70/17 in load range E.
When the installer put them on they were at 40 PSI.
I have them down to 37psi after driving a bit... I don't want to reduce my (already suffering) fuel economy by much, and I definitely don't want to increase the rolling resistance of my lethargic 4R, but I am enjoying a much smoother ride.

Would anyone care to suggest a cold (morning before driving) pressure, or a hot pressure?

**edit** Should I still aim for 32psi cold?

 

Thanks for sharing your tire pressure gauge recommendations. I'll be checking Amazon soon to see what's available.

 

I would leave it at 37. I have the same tire in the 295 size on my Dodge and man those are HEAVY tires. Just that tire regardless of the pressure will hurt the mpg.

 

I am referring to simple sun exposure. Not drastic change in ambient temperature in the desert where temps can vary wildly between night and day.

Interdasting. For the first time in my life, I am perhaps wrong.

 

A looong time ago I would help pit some crazy buddies that road raced at Sears Point (Sonoma now) AFM club racing and if we left a wheel/tire out in the sun it would be up several PSI in no time and we wouldn’t know what the baseline pressure was for sure.
Trucks like our 4R have tall sidewalls which have even more surface area to be affected by the sun’s energy.

 

Painful, isn’t it?

 

My wife parks her car in our garage where the door window hits the left rear. It is always higher than the other three when they are set to the same temperature. After riding around for a few miles, they all register the same.

 

I just picked up my new ORP last week, put approx 50 miles on it before I realized all tire were overinflated by 22 psi (54 psi all the way around) glad I caught it before doing any damage to the tires. I sill got to drop the spare and check that for correct pressure. No washer fluid either or very little - put 1 gallon into the reservoir. Makes you wonder about trans/diff/case/fluids??? I think all the dealer did was put gas in it and run it through the wash. One day transaction! I love the vehicle so far.

 

It’s always smart to get all the fluids checked after buying a used vehicle. One thing I learned from all the YouTube videos is make sure you can get get the refill cap off before taking out the drain plugs on the rear diff , etc…. Would suck if you drained it only find out you can’t get the refill cap off.

 

I always leave my spare over inflated.