New to 3D printing and have a few questions?

Im new to all this 3d printing, but i am pretty good with doing vector artwork in CDR. So not a complete rooky LOL!
A freind bought a Cube 3 and it doesnt do what he wants so he is letting mew use it.
I am looking to make 1/25th 1/24th scale model car parts and want to start off easy so was playing around in 123d design trying to make tires.
I can get the basic shape of the tire but cant figure out how to get the tread into the tire.
So is there any tutorials or do any of you guys know how to do this?
Thanks in advance.
Terry