enclosed trailer with 15" tires?

[Run to Rund]

My 24' has 15" wheels and 225-75-15 D rated tires. Each tire is rated 2500 lb, and the loaded trailer weighs 7000-7500 lb. I run the tires at 65 lb and haven't had trouble. I figured that if 16" trailer tires were the same chinesium, I wouldn't gain much since they aren't overloaded or close to it. Back in 2006 Goodyear published a bulletin saying if you go over 65, up to 75 mph, add 10 psi over what the load would require. They didn't say if you were at max load that you could add another 10 = 75 psi. Since I am well below max, I just run them at 65. It is very easy to add more weight than you think, and overload one or more tires. It is also easy to run too fast on a long trip. I'd say if you are close to max, 10,000 lb, then you would be pushing it to use 15" D tires. E tires might help, but you have also maxed out the axles. If your trailer is over 10,000 gvw, in some states you will need a CDL.