PSI Question

konjis1 · March 17, 2016

So i recently purchased some new tires (Nitto Terra Grappler G2 285/55R22) and wanted to ask what PSI i should be running them at? Is there a specific PSI that GMC says to use? i woke up this morning and all 4 tires were at either 32 or 33...i'm assuming that is too low.

Thanks in advance and happy truckin!

Vic15 · March 17, 2016

Did you look on the door jamb on the drivers door?

SgtShiv · March 17, 2016

I am running the G2's in 285/75R17 and Discount Tire set mine to 40 when they did the install, which seemed fine, but after contacting Nitto they recommended to stay at factory psi. Has been a little over 10k miles and they seem to be wearing evenly so far.

konjis1 · March 17, 2016

Did you look on the door jamb on the drivers door?

I don't have those for some reason as i bought it used.

smrr1 · March 18, 2016

I keep mine at 38 cold.

GMCSierra4x4 · March 18, 2016

konjis1, on 17 Mar 2016 - 06:59 AM, said:

So i recently purchased some new tires (Nitto Terra Grappler G2 285/55R22) and wanted to ask what PSI i should be running them at? Is there a specific PSI that GMC says to use? i woke up this morning and all 4 tires were at either 32 or 33...i'm assuming that is too low.

Thanks in advance and happy truckin!

You didn't state whether or not they are P or LT tires., but the Nitto website states that size is available in LT (Load E) only. The recommended 32 PSI in the door jamb is for a P rated tire and it will not work on a load range E tire for daily driving. Most trucks from the factory with Load E tires have supplemental door stickers with pressures about 15 PSI above the recommened pressure for P rated tires.

A good starting point is maybe 45 PSI front and rear. Buy some driveway chalk (for kids) mark a path a little wider than the tire and drive over it. If you get full contact on the tread, add 5 PSI and try again until the edge of the tread starts to lift off the chalk. Lower the pressure about 5 PSI from that point and you should be good.

spectaculous · March 18, 2016

Door jamb says 32 psi cold, meaning they should jump up to 35 or 36 hot.

I follow that.

Daryl LBZ · March 18, 2016

I run my tires at 35psi front and 32psi rear.

CNC237 · March 18, 2016

A good starting point is maybe 45 PSI front and rear. Buy some driveway chalk (for kids) mark a path a little wider than the tire and drive over it. If you get full contact on the tread, add 5 PSI and try again until the edge of the tread starts to lift off the chalk. Lower the pressure about 5 PSI from that point and you should be good.

Did this for mine 46 front 43 rear cold

tnchevy · March 18, 2016

Go to Toyos website and download their inflation guide for changing tire sizes and going from a P to a LT tire. LT tires require much more air pressure to carry the same weight that the P rated tires do. You could have a blow out running low PSI in an LT tire because of heat being generated. I have to refer to the chart every time I get a new work truck and replace the factor P tires with bigger LT tires. Usually the new pressure ends up being between 44 and 48 psi on every half ton I have had (work trucks and personal trucks).

konjis1 · March 21, 2016

UPDATE:

So let me apologize, in that i do have the sticker inside of the drivers door (i am not sure how i missed that!). Anyway, the door say 35 PSI on OE wheels.

So i called Nitto, and the guy i spoke to said that tires should be 52 PSI cold!!!!!! I asked him if he was sure and he was very confident in his answer of 52. That seems way to high for me, so i will just run them up to 35 PSi cold...no higher than 40.

Thoughts?

Vic15 · March 21, 2016

Sometimes they quote max pressure when cold, which can be found on the side of the tire.

TJay74 · March 21, 2016

You didn't state whether or not they are P or LT tires., but the Nitto website states that size is available in LT (Load E) only. The recommended 32 PSI in the door jamb is for a P rated tire and it will not work on a load range E tire for daily driving. Most trucks from the factory with Load E tires have supplemental door stickers with pressures about 15 PSI above the recommened pressure for P rated tires.

A good starting point is maybe 45 PSI front and rear. Buy some driveway chalk (for kids) mark a path a little wider than the tire and drive over it. If you get full contact on the tread, add 5 PSI and try again until the edge of the tread starts to lift off the chalk. Lower the pressure about 5 PSI from that point and you should be good.

The Nitto's are only 1 load range higher than the stock tires, I ran mine at 36 front and 34 rear for 2 years. They wore perfectly even the entire time with no issues, had 28k miles on my set and they were still around half used when I got rid of the truck last week. I put the new versions on the new truck (Nitto Terra Grappler 275/55-R20 G2) and have them at 35f / 34r and they are doing great so far.

No need to run them at such a high PSI, all it does it gives a rough ride and wears the tire unevenly.

GMCSierra4x4 · March 21, 2016

TJay74, on 21 Mar 2016 - 3:07 PM, said:TJay74, on 21 Mar 2016 - 3:07 PM, said:TJay74, on 21 Mar 2016 - 3:07 PM, said:

The Nitto's are only 1 load range higher than the stock tires, I ran mine at 36 front and 34 rear for 2 years. They wore perfectly even the entire time with no issues, had 28k miles on my set and they were still around half used when I got rid of the truck last week. I put the new versions on the new truck (Nitto Terra Grappler 275/55-R20 G2) and have them at 35f / 34r and they are doing great so far.

No need to run them at such a high PSI, all it does it gives a rough ride and wears the tire unevenly.

The response reminds me of that old phrase..."that is the way we have always done it" ... in response to an injury or catastrophic failure. Low pressure in LT rated tires causes the sidewalls to heat up more. The fact that most people never have an issue running lower pressures leads to the often tribal knowledge to do it wrong all the time. If you want a less harsh ride, stick with P tires otherwise it is best to operate LT tires as designed. I highly recommend using the P to LT conversion chart to get the right pressure. The chalk method is usually pretty accurate and closely matches the conversion table in my experience.

HondaHawkGT · March 21, 2016

This topic was discussed in depth a few times in the past. Most of us running LT Load Range E tires are running 40-45 PSI. If your tires are indeed LT285/55R22's, you'll want more than the 32 PSI on the door jamb, no question. If the tires are P285/55R22's, stick with the cold tires pressure GM provided.