I have three different tire gauges, one digital and two different analog dial type. They are all within 0.5 psi of each other, can I assume that these gauges are all accurate? I mean, it would be really really good(or bad) luck to have three different brand gauges be exactly incorrect together right? These gauges, however, differ from the the tire dealers gauges, how can I tell which is the correct one to trust?

Secondly, I just put LT265/70-17 tires on my 2004 4x4 Supercrew for the upcoming summer trailering season, the placard on the B Pillar says 35psi front and back, but that was for the stock P-metric P255/70-17 only I believe. The dealer put them all at 40psi and they are listed max at 50psi. Is there a good rule of thumb on where these tires should be, I don't think that they had any specific information on their choice of 40psi installed.

On a side note, I am really pleased with the LT tire in the way it smooths out the ride, it did not make for a rougher ride, which I thought it might, the tires just seem to absorb the road instead of bounce off it now.

 

Yes, when you change tires you can disregard what's on the door jamb. If your new tires have a max of 50psi, 40-42 psi would be a good number to run if the ride is not too harsh. I have load range "D" tires 50psi max. and I have been running them at 42-44 psi. and they have been wearing great. Also a little more air will improve your gas mileage. Every little bit help's with the price of gas!

 

Thanks for the info on the LTs, should I keep the front and back pressures the same and/or do the wet tire/dry pavement contact patch trick or just hang around 40-42psi and put this all behind me?

Anyone want to chime in on the tire gauge dilemma I have?

 

If those are a load range C tire with a max of 50, run them at 40, which is what Ford recommends on the door sticker for that LR tire. A D load range might be slightly higher, but not much.