P.S. We use the recommended tire pressure on the inside of closet door while towing not tire max listed on sidewall, over inflation will lower tire life.
(My wife worked in the office for Goodyear when in doubt I ask the expert)
Quote from tire manufacturer
Disadvantages of Underinflation
An underinflated tire can't maintain its shape and becomes flatter than intended while in contact with the road. If a vehicle’s tires
are underinflated by only 6 psi it could lead to tire failure. Additionally, the tire’s tread life could be reduced by as much as 25%. Lower inflation pressure will allow the tire to deflect (bend) more as it rolls. This will build up internal heat, increase rolling resistance and cause a reduction in fuel economy of up to 5%. You would experience a significant loss of steering precision and cornering stability. While 6 psi doesn’t seem excessively low, remember, it usually represents about 20% of the tire’s recommended pressure.
Disadvantages of Overinflation
An overinflated tire is stiff and unyielding and the size of its footprint in contact with the road is reduced. If a vehicle's tires
are overinflated by 6 psi, they could be damaged more easily when running over potholes or debris in the road. Higher inflated tires
cannot isolate road irregularities well, causing them to ride harsher.
The pressure must be checked with a quality air gauge as the inflation pressure cannot be accurately estimated through visual inspection.
A little extra pressure maybe needed with extra load though