I agree, it all depends. Depending on the vehicle I can be above the door jam psi but below max side wall pressure. I doubt I have ever had the full 80 psi in my 2500 HD. On my Tacoma I am above the door jam psi, but if you go to high it can be hard to handle the bumps.
2003 GMC 2500HD Crew Cab 4X4
2002 Trail-lite 7212 21 ft TT
EU2000, 2 boys & Katy the Lab
The vehicle door label is for a "P" class tire, so wrong for the next
higher class tire you went to.
Plus that label is for a tire of 'that' size & rating listed.
There are basically three tire classes for our TVs. "P", or passenger
tire rated. "LT", or light truck tire rated. "Commercial", or what
the semi's use. You went up to the next higher class tire.
Pure danger to use it for another type and size of tire, which really
is part of the spring (hold'm up) system and dampening system (shocks).
Use the percentage of the tire side wall listed PSI to the weight you
expect or if actually weighed, what per axle will carry (divide by 2
for each tire's loading).
Any tire shop person who says to use the label which lists a 'P' rated
tire, is wrong and doesn't know what they are talking about.
-Ben Picture of my rig
1996 GMC SLT Suburban 3/4 ton K3500/7.4L/4:1/+150Kmiles orig owner...
1980 Chevy Silverado C10/long bed/"BUILT" 5.7L/3:73/1 ton helper springs/+329Kmiles, bought it from dad...
1998 Mazda B2500 (1/2 ton) pickup, 2nd owner...
Praise Dyno Brake equiped and all have "nose bleed" braking!
Previous trucks/offroaders: 40's Jeep restored in mid 60's / 69 DuneBuggy (approx +1K lb: VW pan/200hpCorvair: eng, cam, dual carb'w velocity stacks'n 18" runners, 4spd transaxle) made myself from ground up / 1970 Toyota FJ40 / 1973 K5 Blazer (2dr Tahoe, 1 ton axles front/rear, +255K miles when sold it)...
Sold the boat (looking for another): Trophy with twin 150's...
51 cylinders in household, what's yours?...
JIMNLIN wrote: (quote=92DakotaHD (snip)
Some will tell you to max out the pressure when towing which is wrong as well as that would be when the tire is loaded to max capacity (per the sidewall). Most tires will never see that.(/quote)
I haul per max axle loads and only max sidewall psi will work which is the correct pressure.
By the way those tire pressure charts are for "minimum" pressure for that weight which leaves no fudge factor for those road hazard events/max speed driving or days when the temps go tripple digit/etc.
Door placards for tire pressure and tire pressure charts make a good starting place but learn to read your tires for long term reliability and long mileage. Your tires will be happier.
Jim
On a single rear wheel truck hauling a heavy trailer or camper, the rear tires are likely to be near the max, therefore the recommendation to max the rear tire pressure. On a dually, or when hauling light, max pressure is not needed.
92DakotaHD wrote: (snip)
Some will tell you to max out the pressure when towing which is wrong as well as that would be when the tire is loaded to max capacity (per the sidewall). Most tires will never see that.
I haul per max axle loads and only max sidewall psi will work which is the correct pressure.
By the way those tire pressure charts are for "minimum" pressure for that weight which leaves no fudge factor for those road hazard events/max speed driving or days when the temps go tripple digit/etc.
Door placards for tire pressure and tire pressure charts make a good starting place but learn to read your tires for long term reliability and long mileage. Your tires will be happier.
Jim
I said that most will never see it. If you do that's fine. But for instance I have tires on my Tahoe that are rated for about 3200# a piece. The 'Hoe weighs about 5600#. Some people instantly say to air all the way up to Max when towing. In my case, I could put my TT on top of my Tahoe and not be at max load.
I just pointed that out as some people just say air up to 65 or 80psi when towing and that can cause handling problems. I keep my Tahoe at about 50-55 not towing, 65 when towing. Max pressure is 80.
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