Tire Pressure?

burg226 · September 13, 2007

Hey all, i have a 2002 GMC Sierra Z71 with brand new BFG All Terrains on it (265-75-16). On the inside of the door it says to have the tires pumped up to 35 PSI but on the actual tires it states Max 65 PSI. Right now i have them pumped up to 50 psi and the dealer told me that i would wear out the tires much quicker and get worse gas mileage with them up at 50 psi. Is this true? I thought the tires would last longer and i would get better gas mileage with them pumped up around 50psi? Who's right here?

Oh by the way. I do mostly highway driving and at little 4x4 on the weekends. Please advise which would be best to save the tires lifespan and get the best mileage. Thanks for the help...

asilverblazer · September 13, 2007

You will get better gas mileage with the higher PSI, you will also wear them out faster in the center of the tread too.

The maximum on the tire is just that, a maximum. If you plan to load the tire to its highest weight rating you must put that air pressure in them. For example if the tire is rated at 1,000 pounds per tire, that would equal to 2,000 pounds capacity for the rear tires of your truck. You would have to air them up to 65 PSI to load that much on them. However they are likely in the 1800-2000 pounds PER tire range, meaning if you air them all the way up they might could hold 4000 pounds together, your truck on the other hand can not, so you likely will not need all that air in them if you can't even use it.

The pressure on the door is what your TRUCK is designed for, it will yield the best combination of ride, fuel economy, load capacity, and tire wear.

TheHun · September 13, 2007

I went from 33psi all around and got 15.3mpg to 42psi all around and getting 17-18mpg..same driving

hotwheels57 · September 13, 2007

I went from 33psi all around and got 15.3mpg to 42psi all around and getting 17-18mpg..same driving

That's great until you need to replace your $500-600+ tires in fewer miles than you would have at the recommended tire pressure.

redvett · September 13, 2007

The MFR's are required to put the recommended PSI on the sticker so you can inflate to the best air pressure for your vehicle. Adding or subtracting from the sticker will affect the handling and fuel economy so make increases or decreases a little at a time until your happy with your ride.

C & A s Dad · September 13, 2007

Burg, are these new tires LTs? If so they are designed to run at a much higher PSI than P rated tires. I would agree with Redvett but would say that you need to be running somewhere near that max if these are LT rated tires. My Ps are rated at a Max of 44PSI. I run them at 37 to 38 when not towing and 42 when towing.

sledr · September 13, 2007

I run my OE Duelers at 36-37 PSI. On the highway I regularly get between 21 and 24 mpg depending on speed.

Zembonez · September 13, 2007

I always ran the BFG All Terrains on Fred around 35psi. The first set went over 65000 miles and had decent tread left when I replaced them. They ride much better and the tread runs flat to the road surface at that pressure. Higher pressures seemed to make the edges look like they were not touching the ground and the ride suffered. Fuel economy meant nothing to me... It was a truck.

cmoore74 · September 14, 2007

Chalk test for proper inflation to minimize wear. If you've never heard of it google "tire inflation chalk test". You'll see.

Too much air can give an unpleasant ride. The LT tires may be different, but I find (unloaded) 35 in the front and 33 in the rear gives a real nice ride. It's amazing, but you can notice the difference of a few psi in ride quality and handling.

Zembonez · September 14, 2007

Chalk test for proper inflation to minimize wear. If you've never heard of it google "tire inflation chalk test". You'll see.

Too much air can give an unpleasant ride. The LT tires may be different, but I find (unloaded) 35 in the front and 33 in the rear gives a real nice ride. It's amazing, but you can notice the difference of a few psi in ride quality and handling.

BEST REPLY OF THE THREAD AWARD!

I could not agree more.

burg226 · September 14, 2007

Yeah the tires are BFG All Terrain LT265-75-16. I guess i should have mentioned it in the original post. I don't actually tow stuff too often other then a utility trailer with a lawn tractor in it but i've always got something in the bed (bike, sled, etc). I figured i should be safe around the 42-45 PSI. Does this sound about right when the max psi for the tires is 65 and the manufatures reccomendation for the stock tires was 35? I will also do the chalk test. SOunds like a good little trick. THanks for the help.

andyztoy · September 14, 2007

dealer doesn't know what there talking about....

burb2001 · December 22, 2008

Was there ever a definitive answer to this post? I ask because I have a 2001 Suburban 1500 LT and just purchased new tires (LT265/75R16 “D” rated). Previous were “P” rated. I too am interested in the true recommended tire pressure for both normal no-tow driving and for towing a 6000 lbs Travel Trailer (loaded weight) on these LT “D” rated tires coming off of “P” rated.

Shop installed tires with 35PSI. Sidewall says MAX 65PSI (most likely for towing). I would do the MAX but I read on other forums something of concern to consider. It was stated that you need to make sure you have the correct wheels/rims ratings for the selected tires. In other words, my stock GM 1500 LT wheels need to be rated at least 65 PSI or more. If not, it’s possible the wheel/rim could fail due to hi pressure.

Is anyone aware of this and does anyone know what the PSI rating could be on the stock wheel/rim for 2001 Suburban 1500 LT?

asilverblazer · December 22, 2008

Start at factory recommended for your truck, adjust from there as needed. You should not need to adjust more than 5 P.S.I. off the factory sticker. Do the chalk test. it'll tell you. If the center part of the tread is the only thing touching the road, you have too much air, if the edges are the only part touching you have too little. You will never need the maximum capacity of your tires, because you can not put that much payload (not towing) on your truck.

66nova · December 22, 2008

As said before, the chalk test is your best bet. The number on the door only works if you are running the TIRE and Wheel that the factory put on there. Every tire and wheel combo is going to like something different.

I really like the chalk test, because from what I have seen and heard from tire shops, is once you get a wear pattern developing it is really hard to correct it. So from the get go, try the chalk test and you will be better off.

Good luck