Ken,
I too have experienced the thrill of having a trailer tire blow out. It has happened to me 4 times and I never felt a thing. Three times I was alerted by passing drivers frantically pointing at my trailer. The 4th time I happened to pull off the road for a stretch break and saw smoke coming from near the rear of the trailer. Lucky for me that none of the blow outs caused major damage to the trailer.
The first 3 times happened with my 20' travel trailer. The 4th time was with our new 27ft 5th wheel.
To try to prevent that from happening again, I just switched from ST225-75R15E tires to LT235-85R16E ones. This was done at the suggestion of a local frame and axle shop. The clearance between tires is now only 1. 5", but the frame and axle guy said that would be OK. These new tires look, and are, so much more beefy.
I also have added a tire pressure monitor system to monitor the trailer tires. I went with the Doran PressurePro unit. Each tire has a small transmitter screwed onto the valve stem. The transmitters are about the size of a quarter and about 1/2" thick. They each weigh about 2/3 oz. The monitor is approx. 7" x 4" x 1/3" and I mounted it on the dash with velcro. It plugs into a cigarette lighter outlet. In case of a sudden tire failure or whenever the pressure drops about 15% from a set-point, a red indicator will flash and the unit beep. My hearing is such that I probably would not hear the beep, but my wife in the passenger seat most likely would.
I was pleasantly surprised at the accuracy of the system. One cool morning, before the sun came out, I used a good quality pressure gage to set each tire to 80psi. I then installed (screwed on) the transmitters and lo, and behold, the system indicated 80psi for each tire.
I feel much, much safer now that the trailer is riding on the Lt235-85R16E tires and I have a monitor to let me know if there is a blowout.
Also, I can read the individual tire pressures as I drive down the road.
Glenn