Tire Pressure Question / Recommendation

[French_Bulldog]

Hello!

Dumb question - I've got 31" Toyo Open Country A/T tires (265/75r15) with a .ax pressure rating of 45 PSI.

The tag on the door of the Jeep says max 33 PSI, but that's talking about 28" tires (205/75r15).

I've been running my tires at 30psi - but if I can go up to 40psi or so on the street without doing any damage, would be nice to have the added power/economy..

So, what PSI can I go up to if I'm staying on pavement?

Thanks!

 

[Chris]

26-28 psi would be ideal.

40 psi is absolutely ridiculous. Why would you want to do that unless you're looking to spend extra on dental work?

 

[OldBuzzard]

You *can* do 45 PSI. You'll get slightly better gas mileage, twitchy steering, much worse traction, terrible tire wear, and a teeth-rattling ride.

I would stick with 28 on 31s. Tires cost a lot of money, proper inflation makes them last longer than any gas mileage gains are worth.

 

[jadatis]

Only advantage of 40 psi is lower fuelconsumpion.
Disadvantages , bad comfort and gripp, and nervous steering.

Because your new tires are larger then the OEM ( assumed it, did not check the info you gave) they can do with lower pressure then the OEM.

The recomended 33 psi , shall be calculated for OEM tires for GAWR and max technical carspeed, with no reserve build in.

In average use axleloads are lower and max speed used below 160 kmph/ 99 mph , for wich speed the maxload is calculated , given on sidewall.

I can make you a cold pressure/ axleloadcapacity-list for old and new, with build in maximum reserve, at wich comfort and gripp onroad is still acceptable.

For that I give 90% of calculated axleloadcapacity for the cold pressure.
Make them with my made spreadsheet, in wich I use an even tighter formula then the already tight european officially used for all kind of tires, and since 2006 also for P-tires in US.

Then give if wanted in kg or lbs, and if wanted for higher speed then 99 mph.



The 45 psi of new tires, is the max allowed cold pressure, the referencepressure ( for wich together with 99mph reference-speed, the maxload is calculated and given on sidewall) is standardised and 36 psi for standard load ( probably both tires are) . XL/reinforced/extraload 42 psi .
US system P-tires 1 psi lower.

So also check wich you have, and give loadindex or maxload of both.

Googling for it is not always secure.

Then last your rimmwidth.
Ideal for 205/75 is 5.5 ot 6 inch rimmwidth, wich most likely your OEM rimms are.
The 265/75 ideal rimmwidth is 7.5 inch, minimum allowed 6.5 inch.

Or are rimms also chanched when new tires wher put on? Probably not.

 

[suicideking]

I'm running 31 X 10.5 X 15 on one of my TJ's (DD only, no wheeling). I keep it at 27psi. Any higher and the ride gets too rough.

 

[MBDIAGMAN]

Hello!

Dumb question - I've got 31" Toyo Open Country A/T tires (265/75r15) with a .ax pressure rating of 45 PSI.

The tag on the door of the Jeep says max 33 PSI, but that's talking about 28" tires (205/75r15).

I've been running my tires at 30psi - but if I can go up to 40psi or so on the street without doing any damage, would be nice to have the added power/economy..

So, what PSI can I go up to if I'm staying on pavement?

Thanks!

Are you SURE the sticker says MAX?

 

[machoheadgames]

For this tire size, 22 psi would be correct and even if it is too much for the weight of a Jeep. Airing them up to 40 would be ridiculous.

At 22 psi, those tires can literally carry 1,100 more lbs than stock.

 

[Harold&Cat]

I'm running a 235/85r16 which is an E rated tire that is 31.7 x 9 . Max pressure printed on the sidewall is 80 psi . It handles and rides well at 24 to 25 psi . On the trails I run 12 to 14 psi .