It may be the same company (Slovenia based) that make automotive tyres, if it is the company is owned by Goodyear and the plant is one of the most advanced in Europe.
There was some 630-25 tyres on ebay.fr a while back I was going to buy. However the skank wanted more postage to send the whole lot than if I had bought them individually, I told him to Feck off and that I didn't want them that much. :twisted: