$40 tires? I spent nearly $70 each for load range D 12 inch ones and thats not installed. To be honest I have owned trailers loaded down with snowmobiles, way heavy garden tractors and much more over my 65 years of driving and never had a blow out. Some of those tires were old, this is before the 5 year rule of course. I did Insp my tires every trip out, perhaps thats the key.