265 75 r16 tire preasure

[BTlilred]

Anyone have any wisdom on what pressure to run? Just wondering if anyone has figured out a magic number or a base I can start from.

Specs: 09 ranger fx4
265 75 r16 on stock wheels
Passenger tire
Cooper adventurer A/Ts

 

[Doofy]

I have always run the tire pressure listed on the door. Not sure if this is correct or not. I argue a lot with Father-in-Law about this. He says Max Pressure as listed on tire but that seems ridiculous. I tried it and thought I was riding in a hay wagon + the sound of every crack in the road sounded like a gun shot.

 

[pjtoledo]

with that size tire I would start with 32 front and 30 rear, then fine tune it for ride and handling. the 265mm (10.5") width on the 7" wheels may be a bit floaty, a couple more PSI would help with that.
observe the sidewall bulge, there should be some in the front, almost none in the rear (if unloaded).

the specs on the door show the pressure needed with a fully loaded vehicle and factory sized tires. the only time I exceeded those pressures was with my Taurus SHO on a road course. the extra stability was needed then.

last week I purchased a set of 30-9.5-15 mounted on 15x8 for the 2000 ex cab 4x4. set them at 34 all around on a 73 degree day, expecting the pressure to drop 2 lbs now that its down in the low 30s.

 

[BTlilred]

Thanks for the fast responses. Max pressure is definately going to be too much, I was just curious if the door pressure would work for oversize tire. Thanks for the tips on dialing in the pressure and the good starting pressure!

 

[RonD]

I agree, tire pressure is drivers choice for ride and handling, within reason

Lower pressure allows tire's side walls to absorb some bumps, and also has a larger footprint(part of tire that is touching the ground)
i.e. lowering tire pressure down to 12psi when driving in sand for a larger footprint so less likely to sink in.

Higher pressure can make for a stiffer ride and also smaller foorprint for better MPG and less tire wear
The more tire that is touching the road the more friction there is, more friction there is means better traction but also takes more fuel to overcome that friction.
Skinny tires are better for MPG because of less weight and less friction.

Changing the weight in the vehicle can also change tire pressure, how much depends on the tire size and type.
Volume inside the tire can change as you add more weight, but the volume of air stays the same, so as weight is added the bottom of the tire can flatten out reducing the volume inside the tire, but if tire has higher side walls they also deform outward with the weight so volume doesn't change that much.
This is why tire pressure doesn't increase as much as you might think it should as weight is added.
You really don't want to drive too far with deformed sidewalls so it is always good to increase air pressure prior to loading extra weight.


If you live in an area with wide temperature changes over the seasons it isn't a bad idea to run nitrogen in the tires instead of air.
Nitrogen tire pressure doesn't vary much with temperature, like air does.
Racing cars all use nitrogen in the tires, so tire heating up doesn't change the pressure.

And you can mix air and nitrogen, no it doesn't damage anything or explode, lol.
So you can top up nitrogen filled tires with air if there is a leak.
You just start loosing the benefits of stable air pressure in all temps as the percentage of air in the tire gets higher

 

[BTlilred]

My biggest concern is making sure I don't get uneven ware on the tires, I just wanted to see what people were running to get a good base to start experimenting

 

[97ranger xlt]

i have been running with 36 psi all around on 245 75 16's . seems to work well for the type of driving i do which is about 70/30 city/highway. i don't usually carry very high weight wise loads in the bed as a general rule.