Some people have been known to change the hub to have the trailer fit the spare for their car so the donut spare fits. One spare fits all to get someplace to get the flat fixed/replaced
If he did that, it could have a friggin Chevy hub...and he should have told me. I don't have any Chevy wheels to check out this possibility.
From what I can see so far, 5x5 is also a Chevy wheel. I can find that at a salvage yard so I have a spare.
The tires say they were made in 2011 and show no wear except that one has deep surface cracks next to the wheel. Could dog pee do that? Cracks should not normally happen, on one side only,....in six years.
I thought most smaller trailers did use a GM car bolt pattern?