A friend of mine commented on a photo on facebook which was showing a Lego truck, that this would even be better if it had dual tires. This inspired me and I began building a truck around a dual tired axle. And this the result.
historic truck by Versteinert MOC, auf Flickr
historic truck by Versteinert MOC, auf Flickr
historic truck by Versteinert MOC, auf Flickr
historic truck by Versteinert MOC, auf Flickr
Edit: I had to replace the pics by new ones. While cleaning up after cooking... no, after building the truck, I found a brick which actually should be built in the truck. It was then when I realized that there was a hole in the truck which could be seen on the pics. I tried to take the new photos with the same szene and the same angle of view but without the hole.
In another forum I was pointed to the fact that brown was the wrong colour for the bars on which the rear lights are held, so I changed them to light grey on the new photos.