Pressure tires on my F250

[araucano]

Hello everyone:
Ready to head for home once again.I'd like to know:My
truck's pressure by the driver's seat says the following,front tires 50 and
rear 70,air preassure.Since I bought the truck I have changed tires,at the
time BF GOODRICH.Is it safe to go by the pressure indicated by Ford on different tires?Many ,many thanks(just want to be safe)araucano.

[Ray,IN]

If they are the exact same size and load range I would say yes- BUT, your actual load on the tires is the determining factor.

[Grumpytrkr]

When I put the new tires on my Dodge 2500, the Goodyear dealer told me to use the door sticker because I didn't change size or load range. Mine is 60 PSI on the steer axle, and 70 PSI on the drive axle.

Good Luck,

[RustyJC]

As long as you didn't go down from a load range E to a load range D, you should be able to handle the 70 PSIG in the rear tires safely. Especially if you went to a larger tire size, however, you should use the load/inflation tables for that particular tire size and load rating to set the inflation pressure for a given load.

Rusty

[SmokeyWren]

Quote:

Originally Posted by araucano Is it safe to go by the pressure indicated by Ford on different tires?

Assuming the new tires are the same size (or bigger) and load range as the ones on that door sticker, then safe? Yes, but smart? No. Not smart because your tires will usually be over-inflated for the load on the tires.

The PSI on the door sticker is for a truck loaded to the gills. But when unloaded or lightly loaded, you need less PSI in the tires for maximum life of the tires.

Load/inflation tables for tires sold in the USA are developed by the Tire and Rim Assn (RMA). The current RMA yearbook with all the current load/inflation tables will cost you $90 from RMA. But most tire dealers will have the tables available from various tire manufacturers. And here's an older link that includes the tables as of a few years ago. If your tire size in included in that link, then use it.
https://www.rma.org/getfile.cfm?ID=606&type=publication

Then scroll way down in the index on the left side to Load/Inflation Tables for LT tires.

Example: Your current tire size is LT275/70R18E, here's the load/inflation table:

PSI . Max load
--- . -------------
35 . 2070
40 . 2270
45 . 2470
50 . 2680
55 . 2840
60 . 3020
65 . 3195
70 . 3360
75 . 3530
80 . 3640

Weigh the truck on a CAT scale and determine the load on each front and rear tire.

But when loaded for bear if the scale says you have between 4940 and 5360 pounds on the front axle, then you need 50 PSI in the front tires. When unloaded, if your front axle weighs 4,140 or less, then you need only 35 PSI on each front tire.

If the scale shows you have less than 4140 pounds on the rear axle, then you have less than 2070 pounds on each rear tire and need 35 PSI in the rear tires. If the scale shows you have 6,000 pounds on the rear axle, then you have 3,000 pounds on each rear tire and need 60 PSI