16" vs 15" wheels on larger Tt

My 36 ft trailer had 5000 pound axles and 15 inch wheels pretty close to the center of the trailer with a lot of overhang at the back. I've had the trailer weighed a few times it comes in at ~9500, fully loaded, including the 1500 pound tongue. Since I ordered it in 1994, it's had at least 10 blowouts on the rear tires; I know it was the weight and bounce of the overhang. A few years ago, I had new 7000 pound axles and 16 inch wheels/tires installed. The difference is remarkable and I haven't had a blowout since. I did have a flat the second time out on a Goodyear Marathon, which I had always used. This convinced me that the tires were also a problem, so I had all 4 replaced, even though they were mostly new, with Continental's. That was 3 or 4 years ago, and no tire problems. If I ever get a new RV, it will have 16's; I won't even consider anything less for a larger trailer.