I was taught in school (San Jose State Engineering Department) that tire manufacturers DO NOT set the minimum and maximum PSI - they only set the MAXIMUM LOAD and the PSI needed to properly hold the load and maintain adequately low sidewall temperatures. It is then up to the manufacturer to determine the PSI needed for the load that specific vehicle needs. Maybe the info was wrong - so I will let you teach me using the below examples.
MAXIMUM load 2405 @ 50 PSI (COLD) (stock Rubi tire).
MAXIMUM load 3195 @ 65 PSI (cold) (replacement pitbulls)
That's exactly what it says on my JK tires (and same wording different numbers on the F250, the caddy, The GTO, and the trailer).
Please bold the "MAXIMUM PSI" language in a re-quote for me.
THEN you may want to re-write all of Goodyears "Safe Loading and Inflating Guides
" where they give the exact same explanation I was taught and specifically state ALWAYS SET TIRES COLD - AND DO NOT
BLEED OFF HOT PRESSURE GROWTH. Who knows they may pay you for correcting them! After all if THEY are wrong they could be SUED as folks COULD die when SUVs have blowouts on the freeway.
Registered to this forum to give more information about tire-pressure.
End 2007 I got hold of the formula that the European tyre-makers use to determine the advice pressures , and went running with it.
Learned myself Excell to make spreadsheets for it, and translated a few to English to go worldwide with it.
Came to the conclusion by reacting on several American fora, that there are a lot of loose ends at the way it is calculated , especialy in America, but also in Europe the maximum load of some tires is given to high ( low aspect ratio tires and Off-road(looking) tires with profile that cover a lot of the sidewall).
Planted a lot on my skydrive that belongs to my hotmail.com adress with the same user name as here.
Dont have a Jeep , so wont introduce myself in a seperate topic.
Also I am not a tire-specialist, but think I know more about this pressure-part then many in the field.
So now my reaction here.
I would like to discuss further with mr Bishop , mayby by personal message or by mail ( cripted already my E-mail to prefent spamm), think I can learn more from you. Edit: reading back I see tha starscreem seems to know more about tires too, so for you the same story.
But to react to your reaction.
The @pressure that is written in your example is almost always used on C-load/6ply tires and up, and is not the maximum pressure of the tire.
In the formula sheet it was called the reference-pressure, is the pressure at wich the maximum load can be caried riding up to maximum speed of tire, or if lower 160km/99m/h, without damaging the tires by driving alone.
If you read "maximum load xxxx lbs AT yyy psi(cold)" then the yyy is always the reference-pressure ( furter Pr) ,saw it written also maxloadpressure.
TRA ( Tire and Rimm Assosiation) even allowes 10 psi above this for higher speed and more maximum load at low speed, and better riding quallity for LT tires , and even 20 psi for Truck-tires.
But for Jeep tires this is not needed, they are that oversised that a low pressure can carry the load savely.
On the other hand Jeeps have often those off-road ( looking) tires with the large profile blocks that cover a part of the sidewall, so that sidewall may not deflect that much as the tire-maker used for their calculation of the maximum load, I calculated that you have to substract mayby even 20% of the maximum load printed on the sidewall.
To cut my long first post short, If you have C-load/6ply (Pr=50psi)tires or up, you have to use higher pressure for the same load , then a normal P-tire with its Pr of 35 psi for american tires ( Pmax 41 to 50 psi only printed on the sidewall.
If you want me to calculate an advice-pressure with my own system, give me the GAWR's or real weighed axle or wheel weights in the way you drive the car. From the tires the maximum load and Pr or kind of tire , and I will calculate the lowest pressure at wich no tire damage happens. Above that is allowed , but if you go to high, comfort and gripp gets lost to much.
Or try it yourselfes with one of my spreadsheets, there are a lot English on my skydrive between the Dutch.