I currently have a 2000 sr5 4runner which i purchased in late january, it came with brand new goodyear wrangler rt/s tires. I recently noticed that one of my tires has been losing air often, I put air in it and was able to get it up to about 40 psi, the sidewall of the tire says the max psi is 44. recently i checked the tire pressure and it seemed to come back down to the low 30s regarding psi. the other wheels seem to be within that same range but sometimes it seems as though they are low on air.

My question is, what is a good psi level for this type of tire, 265/70/16. I did look up the reviews on tire rack for the tire and it was quite poor, the tire choice was not mine since it came with the car when i bought it. I dont have any extra cargo which could bring it down, just a rim from the spare tire in the back and umpiring equipment bag.

Any thoughts would be appreciated

 

Personally I try to run my tires at as high a pressure as possible. I go with the max pressure for the tire to have a flat footprint. This will help with gas mileage, but make the ride a little stiffer. I have a similar size on my 4runner and run them at max pressure, which I think is 35.

 

The tire pressure is regulated by the tire style and how many ply it has. The recommended pressure that's in your manual can be way off. Look on the side of the tire and see what the max is. I like to start out #5 less than max and work from there.
Go to a nice paved parking lot and using a piece of chalk or crayon place a line across the tread on the top of each tire leaving a mark on the side wall as well so you can tell where you marked the tire. Now drive straight forward for about 20 yards and stop easy. Get out and look at the chalk marks. If the line is gone all the way across the tire you have perfect inflation. If the mark only shows on each side the pressure is to high, If it only shows in the middle it's to low.
The chalk mark method doesn't lie but some people still insist on keeping the inflation right where the manual says or keeping it way to low because they want a smoother ride and that's fine if you have the money to replace wore out tires all the time.
Under inflated tires will make a big difference on gas mileage due to more friction on the surface. Hope this helps, Mike

 

ahhh chalk on the tires...great suggestion there....thank you

I had never heard of that before...

 

I think this is backwards.

 

no it's correct because if you over inflate the center of the tire bulges and the sides never touch leaving the chalk on the sides. If you under inflate the sidewalls collapse and carry the weight and the center of the tire never makes contact leaving the chalk in the center. So again

chalk line in middle=under inflated (add air)
chalk line on outer halfs=over inflated (release air)

 

i thought it was backwards too but he meant chalk on the tire, not on the pavement.

 

Lol, No not on the pavement. Mark the tire's. If the chalk wears off the center of the tire only then the pressure is to high. The high pressure causes the tire to swell in the center only. The center swelling won't allow the edges to touch the pavement.
If the tire pressure is to low the center will concave and only the outside edges will touch the pavement and not the center of the tire.
If the chalk disappears all the way across then you have perfect tire pressure and your tires will last much longer, handle better and help with gas mileage.
Hope this helps and I'm sorry if I confused anyone. There is a link to this "chalk the tires" article somewhere with good pictures and a better explanation than mine. If I find it I'll post the link here. It's a great article with good down to earth info on this subject. Mike

 

Besides everything else that folks are saying, you've got a leak - it should get fixed.

Do you have a Les Schwab in your part of the world? They'll usually do leak fixes for _free_.

 

maybe your valve stem is a little loose....(hopefully) I think there is a special tool for it though, stop by a tire shop and ask to use theres and check the tightness. if it moves, prob solved! happened to my girls car last week

 

My Nittos are happy at 35psi.

 

big-o tire down here does em for free

 

Cool. I think a lot of people do 'em now.

I didn't know where PF was from (why don't people at least put a state in their profiles?) so I just went with what I thought was something big.

 

Grounded, The NasCar drivers use the same method as well as many other racing outfits. Just go to Goggle and type in " Checking tire pressure with chalk" and you will see all the hits and people who use it.
I check mine several times a year that way. It just doesn't lie, Mike

 

This is a link to the site I was looking for. It will give all the info with great pics and it's just a good article about tires off and on road. Good reading for anyone who wants to learn a few new things about there tires and how they react. Mike
http://toyotatruckworld.tenmagazines...rticles/31802/

 

Fixed link: http://jpmagazine.com/techarticles/31802/

 

Thanks Midiwall. I owe you one Mike

 

Actually, it looks like the one you posted _will_ get you there, but it goes through a redirector/referrer that stumbled for me the first time I hit it. No matter!

 

Let us know what your findings are when you do this test and what pressure you ended up with to make it right . Thanks, Mke

 

Dont forget each rig is different, based on alt/temp/weight/tire mfg. But it will give you a baseline to dial your own pressure in.

I also have been thinking about aftermkt wheel temp/pressure sensors with in cab monitering...then you get a good footprint, and can moniter for optimun temp...