wolfe10 wrote:
Boy, this thread has run the full range from accurate to bizarre.
FACT: The GVWR sticker installed by the coach manufacturer is for the OE tires (yup, they DO know what they put on there) when loaded to GAWR.
Please provide facts that are contrary to this statement.
And, no, I would never suggest any method of accurate tire pressure determination without weighting each wheel position. Then, take the heavier wheel position on each axle to determine the correct minimum PSI for all tires on that axle from your tire manufacturers inflation table.
Unlike car tires, the correct PSI for the tires on our coach (per Michelin, not me) is 70 or 110 DEPENDING ON LOAD. That is a huge range and over or under inflating is quite likely if you don't know your actual weights.
The placard installed on our 2001 Winnebago Adventurer reflected the recommended tire pressure for the tires originally installed on the vehicle. It came with a placard indicating the minimum tire pressure should be 70 psi. About a year after we purchased it Ford sent a certified letter with a new placard recommending the minimum pressure be increased to 75 psi. Also included in the letter was an updated placard raising the lug nut torque from 140 ft. lbs. to 160 ft. lbs.
The motorhome came with Goodyear G670 tires size 245/70R19.5. The Goodyear load and inflation table recommended a minimum of 70 psi for tires built before 2002, and 75 psi for those built in 2002 and later. Since tires built before 2002 would now be a minimum of 13 years old that spec is no longer mentioned in the table. The latest version of the table recommends a minimum inflation of 75 psi.
