Unimog S404 wheel specifications
Standard rim size: 9.00 x 20
Standard tyre sizes: 10.00-20 or 10.5-20
Optional rim size: 11.00 x 20
Optional tyre sizes: 12.5-20
Here's another pic of those tyres:
Source:
http://www.die-rheinhessen-kriecher....1/404res_1.HTM