Tire Pressure
Junior User
Joined: Feb 2002
Posts: 57
Likes: 0
From: Damascus, AR
The inflation numbers molded into the sidewall of the tire refers to the tires maximum load rating. The numbers on the door are the recommended inflations for the vehicles maximum load rating, which is usually less than the tires ratings. If you are running tire pressures at the tires maximum load, you are most likely overinflated.
Postmaster
Joined: Dec 2002
Posts: 3,959
Likes: 9
From: USA
When your truck is loaded you should run your tires at the max pressure, as stated on the tire's sidewall, measured when the tires are cold. Underinflation and overloading are 2 main causes of tire failure in trucks loaded with weight. Your fifth wheel trailer likely puts a heavy load on your truck's rear tires. When unloaded, you can drop the pressure for a better ride, down to say 70% of max.
The tire pressure listed on your truck's information sticker applies only to the original tires that were on the truck when it was new. If you have changed brands or sizes, follow the information on the tire sidewall instead, for max pressure rating.
You may want to weigh your truck and your trailer axle by axle on a truck scale to find out if your truck is within it's maximum weight ratings for GVWR and rear axle weight rating when the trailer is loaded and check that information against the max load rating printed on the tire sidewalls to see that you are not overloading your tires.
The tire pressure listed on your truck's information sticker applies only to the original tires that were on the truck when it was new. If you have changed brands or sizes, follow the information on the tire sidewall instead, for max pressure rating.
You may want to weigh your truck and your trailer axle by axle on a truck scale to find out if your truck is within it's maximum weight ratings for GVWR and rear axle weight rating when the trailer is loaded and check that information against the max load rating printed on the tire sidewalls to see that you are not overloading your tires.
Junior User
Joined: Feb 2002
Posts: 57
Likes: 0
From: Damascus, AR
There was some good information presented in a thread on inflation levels and fuel economy. You might check it out here. https://www.ford-trucks.com/forums/s...d.php?t=297573
