My pup tires were manufactured in 2013 and had a highway speed rating of 62 mph so I decided to replace them with a little beefier tires that have a 81 mph rating. While I was at it, I figured that I may as well do the same with the boat trailer since they were identical size with a 65 mph rating. I figured that the tires on the boat trailer weren't due to be replaced until next year at the earliest since I just replaced them in 2014. I was also considering that they get beat up on the Canadian logging roads when I take my yearly fishing trips across the boarder. I also though it would be nice to have a higher rated tire and that I could use the old tires as the spare tires on both the pup and on the boat trailer so they wouldn't be "wasted" being fairly new. I removed the boat trailer tires and rims and brought them in to have the new tires put on. I also grabbed the spare tires off of both the trailer to have the old tires put on the spares. When I was unloading the tires from the back of the truck, I saw that one of them was missing a large chunk of tread about six inches long and two inches wide and the hole that remained was well worn right down through the first layer of steel belts. This was a disaster waiting to happen. I have no idea when the tread had come off, but by the looks of the wear, I had been using them long after the damage was done. I was VERY lucky that the tire had held up as long as it did. Here is where you can learn from my mistake: CHECK YOUR TIRES. Check them on a regular basis and don't assume that because they are new or fairly new that they are good to go. I got lucky. VERY lucky.