Got my Gateway 3200 last month with Towmax tires. Talked to a tire person and he said that the RV manufacturers were putting tires on the trailers which were maxing out the tires and these ST's should be replaced with LT's on the heavier rigs such as mine. He said that the Towmax tires would have probably been fine on a lighter rig. I followed his advise and went from Towmax 235 by 16 to Sailun 215 by 17.5 (almost same diameter) which are 16 ply tires and will stand up to the weight, speed, and heat. I also had to replace the wheels which were rated for 110psi and got new ones which were rated for 200psi. Cost me some money but I will not have to pay for damages (or personal injury) to my 5th wheeler due to Towmax tires blowing out. Cheaper in the long run.