I remember quite some time ago disucssions on tires. I had a tire go bad yesterday and another one that needs to be replaced, based on that I will replace all four. Been doing some looking and find that the Goodyear Endurance and one of the Carlisle tires are D rated and have a higher speed rating. The tires I have are Trail Masters which came on the Boatmate trailer when I picked up the rig in Aug 2014. I probably have 10,000 miles or close and couldn't believe when I pulled the flat and looked at it. Curious what others have done with tires, trailer tires, lt tires or car tires. I put the spare on so I'm not in crises mode at this time.