Hayseed, thank you very much.
wedgetail84, thank you very much.
Maybe you will find answers to these questions and some more in my website. You will even find a tutorial on making the tires there.
More pictures of the truck in my website
Now the scale Caterpillar is done in two versions: one new and the other is with weathering effect.
The new pictures of this Catertpillar are only in my facebook Ivan Gouveia Oficinaaberta