Tyres not an issue, not sure about the fence tho
On Russian tyres, there are canvas layers all the way through the tread, and they are checked for end of life by taking a small "plug" of rubber out of the surface, and ensuring that there is still canvas present in the plug. Once it's no longer pulling canvas, then it's time to replace it.The tool is similar to the sort of thing used to take a core out of a cheese.
That's the story I got given by a flight engineer that spoke very good english when I raised the same question a while back when a 154 was coming through Dublin on a regular basis. He was very helpful about a number of issues related to the 154, and I've no reason to doubt his accuracy or credibility, as he did show us the plug holes in the tyres where they were checked, and of course, they were different depths as the tyres wore down.