tire pressures
Cargo Master
Joined: Aug 2009
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From: Olathe
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From: Sioux Falls Area
for a more indepth and scientific approach:
https://www.ford-trucks.com/forums/1...ttle-stiff.htm
for the short version, go to post #5
for the long version, go to post #10
essentially, it is a ratio of the load the tire will see in service compared to the maximum load on the tire at the maximum rated pressure.
for the in-service load, i use the GRAWR.
so.... i would use:
GRAWR/(Max load on tire X 2) x Max pressure on tire.
that is the minimum.
https://www.ford-trucks.com/forums/1...ttle-stiff.htm
for the short version, go to post #5
for the long version, go to post #10
essentially, it is a ratio of the load the tire will see in service compared to the maximum load on the tire at the maximum rated pressure.
for the in-service load, i use the GRAWR.
so.... i would use:
GRAWR/(Max load on tire X 2) x Max pressure on tire.
that is the minimum.
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Brett Foote
Elder User
Joined: Jan 2010
Posts: 790
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From: Ontario, OH
i put some 275/70R18 BFG AT's on my truck. the y are E rated tires that has a max PSI of 80. I put mine at 50 for a few thousand miles until i noticed the centers wearing faster. I put them at the recomended 35PSI the door sticker recommended and have had no issues with loss of mileage or handling.
Cargo Master
Joined: Sep 2005
Posts: 2,977
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From: Montana
i put some 275/70R18 BFG AT's on my truck. the y are E rated tires that has a max PSI of 80. I put mine at 50 for a few thousand miles until i noticed the centers wearing faster. I put them at the recomended 35PSI the door sticker recommended and have had no issues with loss of mileage or handling.
My Toyos are in the same boat; 80psi max. I run at about 42 psi empty, 45 when towing, and have no complaints. If you run the pressure too high, I have been told the TPMS will be triggered.
Mountain Pass
Joined: May 2007
Posts: 223
Likes: 2
Go off of what the tire recommends. Add more than recommended for better gas mileage(but not more than max).
Going off the door sticker makes no sense if you changed tires out. The sticker on the door is for the stock tires not the wheels with any tire in the world. Higher load tires require higher PSI.
Going off the door sticker makes no sense if you changed tires out. The sticker on the door is for the stock tires not the wheels with any tire in the world. Higher load tires require higher PSI.
Resident smarta$$
Joined: Aug 2006
Posts: 4,929
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From: Oaks,PA
I run 48ishF/45R in my Nitto TG 295/70-18s and they have worn pretty evenly over the last 15k. The tire place that installed them had them around the psi on the door and the fronts started cupping. You could always do the chalk line thing across the treads
Elder User
Joined: Jul 2010
Posts: 501
Likes: 1
From: Pacific NW
I have 20" rims on my truck, but my spare is an 18" LT tire. the recommended pressure for my 18" spare is 50psi per the ford tire pressure sticker. I personally like to run a higher pressure and would probably run it at around 55 to 60 psi since those load range D tires can usually take about 60 or 65psi. I know load range E tires can take 80 psi. I like to run higher pressures for better fuel mileage.
Last edited by Jus2shy; Dec 1, 2012 at 04:22 PM. Reason: clarification