Liked the thread posted on the FAQ page so much that I posted it in it's entirety onanother site doing a topic on correct tire pressures that refuted one statement made by our old resident engineer. It made sense to me when I read it but now have to disagree. (By the way, I could find no method of replying to the posting on the FAQ.)
I've always gone under the assumption that tire pressures should always be checked "cold."
However when the FAQ posting recommended checking pressures if you are using the max allowable for safety which are molded on the tires sidewalls you should check them hot so that if you took the tires out on an interstate with the max allowed set at a cold temperature, because of the tires heating up the max allowed would be exceeded. I bought this until it was brought up that tire manufacturers know PSI rises with hot tires and have taken into account this occurrance when they posted the max PSI on the sidewall. Makes much more sense than the statement of the engineer in the posting.
So I'll continue checking my tire pressures "cold" even if using the max allowed molded on the sidewall.
(I think you will have to read this at least twice , but "you get the point".)

 

zinzin,

i see a mis-understaning here.

the LOW range pressure SHOULD be done cold cuz
if it done while HOT, you be under-inflated when the tire gets cold
and you be running underinflated for the 1st few miles each day.

should one choose to go the max (not sure anyone does) one is adviced
to check the pressure while hot then they would always be within limits.

most passenger cars increase around 4psi, racecars increase around 20psi,
loaded light trucks increase more than 4psi.

my truck tire maker, BFG KO's, recommends just that.
on these tires, i tend to run about 38psi in the city, for comfort,
then to the max on the highway in long trips, or truck loaded or both.
the local rep is in the opinion that the door label is the only option
regardless of load - uniformed?

running pressure at the max helps keep tires cooler by minimizing flexing,
fuel economy and efficency is augemented a bit. something that i like when
i'm cruising on a 1,000+ mile trip at 80mph' loaded with 5 to 6 humanoids,
a dog, and around 1,000 lbs of cargo - for a grand total of just under 8,000 lbs.

in comparison, the Allante & the Stang run 36psi in city and 40psi in long trips on
the hwy. the tires simply bite better at 36psi than at the min 26psi - MUCH better ..
inflated to 40psi for running at triple digit speeds, fears of blowouts are minimized
and traction is at its best ..

lastly, when going to SMOG TEST, inflating drive axle tires to the very max is adviceable
to run the engine more efficiently and boost chances of passing test.



.

 

I understand that Zal, but my thoughts are no different with putting in the max at a cold temp setting as I have always done in the morning before car is driven. The point made on the Prius net where "EVERYONE" runs with the max pressure moulded on the sidewall, (44 PSI) and they do this in the morning and with the cold temps which any tire company will advise using. I believe they are correct when they say there is absolutely no danger in doing this as the manufacturer expects the 44 psi to be used when tire is cold and expects the at least 4 degree rise with no problem.
I, at first agreed with the premise of using a hot tire if you were going to go the max route but I can also see now that this would not be necessary.

 

zinzin,

also, my guess is that at max pressure, cold of hot, the change in pressure is
little since the sidewall flex is very little if any. you are probably talking about
tar mat heat for the most part .. probably nothing to be concerned about.

i do check the tires cold, i dont think i have ever been to the max rating
so i really dont think about it much.

ok .. i am going to see what it is on the 4x4 ...

back ..

tires are rated at 2,270 lbs each, at 50psi COLD
that would be 4,540 lbs per axle or 9,080 lbs for vehicle

door label says, inflation to:
- front 35 psi, 2,800 lbs for axle
- rear 41 psi, 3,750 lbs for axle

from that, i say you are right on.
my tires have it stamped on the sidewayy, 50psi COLD.

i dont know what the OLD tires stated, cold/hot/nothing ..
wait i gotta check ..
Goodyear Warngler A/T, max capacity 1990 lbs at 50 psi COLD

i gained 280 lbs capacity per wheel ...

i may try it at 50 psi in the city and i hope i dont
shatter or crack any teeth or bones.
my 4x4 is pretty stiff and also has 1,000 lb spring overloads.
meaning i can still load up to the 8,000 lbs and hook up the trailer
with a tongue weight of around 500 lbs.

hey PRIUS, dont cut us off cuz you gonna lose !

=======================================

i believe an update to the FAQ is in order by way of this discussion
and what was learned.

thanks zinzin

the tire pressure FAQ is :

https://www.cadillacforum.com/fb.asp?m=8172