What PSI should 35x12.50x17 BGFs Ko2, truck weighs 7000lbs

Just got some new 35x12.50x17 BFGs Ko2. Thought I would stop by a weigh station to see how much the truck weighs over all. With my 2020 CM and nobody sitting in it, it says it weighs 6,550lbs. With 2 adults it weighs in at 7,000lbs. I have a Leer canopy, AMP Research Power Steps and DECKED truck bed organizer that's 3/4 loaded with tools etc. How many PSIs should I be airing my tires to, same all the way around or more in the back than the front? Any advice or suggestions for the PSIs for the best wear, even wear and longevity would greatly be appreciated. Thanks!

 

For comfort - I run 38-40psi all around. Mine is a tiny bit heavier than your truck. Ideal wear is probably a little higher - 45-50 maybe.

 

Yeah I like 47-48psi

 

Load range E? I can’t remember if those are one of the oddball sizes that come in a D or E rating.

 

Yes

 

Load inflation tables sat 38-40 psi. Bump it up 5 psi if the ride feels sloppy or sluggish.

https://www.toyotires.com/tires-101/tire-load-and-inflation-tables

 

Do guys take readings cold?

 

So how you do these calculations is finding what your tire placard says your tire pressures and tire size is. Mine was P275/65/18 at 30psi front 33psi rear. So we find the pressure those tires hold at 30 and 33. So for 30 it’s about 2400lbs and 33 it’s about 2550lbs. Now P rated tires on a truck or suv actually are d-rated 10 percent. So your 2400 lbs is actually 2181 lbs when you devide 2400 by 1.1 . So now we know that the tires need to hold 2181 lbs in the front and 2318lbs in the rear to meet the manufacturer max load of the vehicle. So now go to the load inflation chart and find what your new tires are and what pressure meets 2181 front and 2318 rear. For me and my 35/12.5/17 toyo RT trails I run 33 front and 36 rear and that meets the weight of the truck to the weight the tire can handle at those pressures. Now this d-rating P-rated tires is only done to P-rated. If your tire placard on the driver door sill does not say P before the tire size then you have a Eurometric tire and that does not get d-rated. Good luck!

 

Yes. Doesn’t matter what it is hot - the tire is designed for the pressure increase from the tire heating up. Cold is the correct way to read and fill the tire.

 

OP I'd do the the chalk test to get a perfect number for your specific rig/tires.

Chalk Test:
1) Buy or find some sidewalk chalk
2) Find a straight, level, smooth stretch of road (200m)
3) Draw a 2" wide chalk line across the tread of 2 tires (1 front/1 rear)
4) Drive a couple hundred yards and assess the wear based on what chalk residue remains.

*Ideally the wear would be even across the tread width. If more chalk remains in the center, you're under inflated, if more chalk remains on the edges, you're overinflated. Repeat the test as many times as you need to find the right number, which will likely differ from the front tires to the rear by a couple PSI.

 

This

 

My gripe with the chalk test - tire dynamics and shape are way different at 75-80mph than the 15-20mph that most people perform the test at.

 

This is true. Also, MFG's are starting to manipulate tire shapes a little. Look at the cooper AT3; the tread face is purposely crowned so it could very easily show a different chalk test.

 

Good point. Still not sure there's a better way to go about it though

 

I’d argue the load table being referenced is a better tool. Post #6.