I'll try to be kind about the tire Nico

but no guarantees.. to say it kindly, yes it needs more work but atleast it looks like a tire so you're on the right track.
But try to model this in Rhino instead of using Silo, it would be alot easier. Then you can just do it by model one thread section of tire, then multiply that and wrap it around your tire shape. It saves a ton of work. However if you have to model this in Silo, it needs some sharper edges to look more like the real thing.
Besides that, keep up the good work.
/ Max