It's a trailer tire. They're all crap.
These ones were on the trailer when I bought it 3 years ago. The seller said they were new from a year ago, so put them at 4 years old. I've probably put 6000-7000kms on them since I've had them.
The lesson here is that I had a spare tire, and all the tools required to replace it. And I did a walk-around the trailer before leaving and caught it before we hit the road, so it didn't blow out while we were driving home.