My Marathons were also bad. I have an 06 LSV. Those tires always buldged no matter the air pressure. They were load range D. In my opinion that is not enough tire for a LSV sitting on a single axle. After one of mine blew out this summer I went to the load range E Carlisle radial trailer tire. They seem to do much much better. Size wise they are the same except they are a stronger tire with a heavier side wall.

Also, someone mentioned above that their tires appear to lean in or out when the boat is on the trailer. I had that issue last summer and the axle broke soon there after. Make sure you contact Boat Mate trailers if your tires/ wheels lean in or out when loaded. The axle is likely bad. They know about this issue....