What amount of air pressure to run in bigger tires?

Hey guys, just got a set of 285/70/17s - Hankook Dynapros. The max is can put in is 80 pounds of pressure, but I can't seem to find what the appropriate amount to run in them is ? What are you guys running in your 285/70/17s?

 

im running 35 in mine toyo open country

 

Off topic , but did you get the AT or MT Dynapros ?

 

Chalk line test- Draw a line across the whole tread and drive a little- See how the chalk wears off. If it's even- That's the perfect pressure for tire wear. If the outsides wear more than the center- Too low-add air. Inside wears off and outsides stay- Too much air- let some out.
Once you know that "perfect" pressure-You can add air to improve mpgs (to a point) at the cost of a stiffer ride. Less air will give you a softer ride. So it's kind of your call from there.

 

I got the AT's

 

what load rating are they?

 

Load rating of the tire has nothing to do with how much air you should run in it. Run the factory specs or close to it. The higher load range tires are deigned to be able to air up to a higher pressure IF NEEDED for heavier loads. You wont run loads that heavy so run the correct pressure for your truck... around 30-35 psi. People who do stupid stuff like run 40+ psi are just getting a Fred Flintstone ride for no reason.

 

Should be a sticker inside the drivers side door pillar that tells you what psi to run, it's mostly based on the gross vehicle weight rating of your truck. Mine says 29 psi front and rear. The tire manufacturer has no idea what you are mounting their tire to, they just put the maximum pressure the tires are capeable of on the sidewall. Running them way over inflated makes them wear out in the centre as everyone has already said. Start with what is written on the sticker on your truck then do the chalk test to make sure you've got it right, it will likely be a slightly different pressure depending on what type of tire you've got and what size you've got. I run the same pressure in my 265/75R16 as I did in my 245/76R16. Currently I am running 32psi front and 30psi rear.

 

It's not NO reason. They're also prematurely wearing down the center of the tires.

 

2010 ass cab stock wheels called 4- 30psi front 33psi rear. peanut wheels!!. 245/75r16nz. i run 35 psi all round seems to be work`n fine.

 

Call the Tire Rack. Ask to talk to their tire pressure expert guy. After you tell him exactly what vehicle you have and your tire sizes, he will calculate for you, what pressures you should be running, based on vehicle weight and internal volume of your new tires. Worked for me.

 

When you say "worked"- Did you compare to something else or are you just going off the "I'm happy with how it rides and the tires wear looks decent" method??

To the folks above talking about the door plate-That really only applies with the OEM size tires from the same manufacturer. And even then it can vary a few PSI based on compound composition, time of year, and individual truck options packages/extra gear.

 

Good info. Thanks. You a mechanic or just know what U R doing ?

 

Not a mech...and even saying I know what I'm doing is a stretch. I just have learned a few tricks from some smart dudes and realize that they work.

 

im running 285/70/17's BFG's ATand the mechanics at Discount tires told me to keep it at 50 psi for maximum tread life.... not sure becuase ive always had my previous Toyo's AT tires at 33 psi and lasted long time

 

I run 38psi in my 285s.

 

Wow 50? Did you take his advice? I would do a chalk test 50 sounds like a lot. 33 sounds better to me

 

Well, thanks for passing them on !

 

just for example:

I have goodyear Duratrac's 265/75R16, larger than the 245's that came with the truck.

Did the chalk like test, as i do with all my tires

Found the best pressure for MY TRUCK, with MY TIRES

to be 36 p.s.i. up front, 24 p.s.i. in the rear.

I believe the 24 p.s.i. is because the back end is so light, carbon fiber bed and all.

have been running this for a couple years now, summer, winter, year round.

Have had no problems, runs great at highway speeds, haven't got stuck in snow yet.