How to determine your new air pressure with LT Tires.

I got falken wildpeaks at 35 psi cold pressure. More than that is too harsh of a ride for my comfort. My tire wear is fairly even across the tread pattern.

 

Apologies that this post isn’t actually related to LT tires.

What would you inflate these tires to?
Towing mostly on fairly flat paved highways and regional roads.

Travel Trailer:
2015 Shasta Airflyte 16’ Reissue
GVWR 3635 lbs
Tire Loading decal states 35PSI and P225/75R15


Tires:
Diamond Back whitewalls which replaced the original P tires
ST225/75R15
Max 80PSI Cold
Load Range E
DOT date 29 20

 

Even though these tires will significantly exceed the load requirements (based on the GVWR of the trailer), you need to inflate Load Range E trailer tires to their max of 80psi (cold); anything less than that and the tire will be susceptible to overheating and blowouts.

 

Thanks. But I found this formula.

Looks like around 52PSI would be suitable for us.
2830/80=35.375
3635/2=1817.5
1817.5/35.375=51.378

TIRE INFLATION EQUATION:

Tire Weight / Tire Pressure = Load Capacity Pounds per PSI
Example:
At 80psi, a 265/75R16 10ply itire will carry 3,085 pounds of load.
At 60 psi on a 10ply tire, the tire's load carrying capacity is reduced to 2,314 pounds per tire.
If the customer runs 65 psi in a 10 ply tire, his capacity is now able to carry 2,507 per tire.
Tire Weight / Tire Pressure = Load Capacity Pounds per PSI

Here is this formula using a 265/75R16 E with 60 psi in the tire;
3,085 / 80 psi = 38.57 pounds of carrying capacity per PSI.
38.57lb X 60psi = 2,314 load carrying capacity

 

Your formula and math are fine. However, load carrying capacity is only one issue to be concerned with when determining proper air pressure of any tire...

However, ST (specialty trailer) tires are a different beast than P rated or even LT rated tires. They are meant to be used at or within very close proximity to their max PSI (probably should be labeled w/ 'Operational' psi instead of 'max' psi to avoid confusion; but DOT requires the sidewalls to list 'max' pressure).

...Anyhow, an E load rated ST tire and an E load rated LT tire are constructed quite differently and require different air pressures and considerations when being used. Another consideration of a tire's capabilities is its speed rating. ST tires are only rated to a max speed of 65mph at max pressure!!! At 52psi, you'd be operating the tire with only 65% of its max air pressure, and you'd have a significant reduction in the tire's ability to properly dissipate heat (especially at fwy speeds) before risking it to potential failure due to over heating. What would the new 'speed rating' of the ST tire be at a reduction of 35% of its max PSI??? I don't know, but I'd guess it's slower than you'll be pulling the trailer at on the highway.

It's your rig and your trailer, but I'd strongly encourage you to do some more research into recommendations on air pressure as it pertains specifically to ST tires and not just search for 'load' formulas. Under inflated trailer tires are dangerous to not only you but also to the people on the road around you.