Forgive me if I am mistaken, but aren't tire designs being withheld by the manufacturer's of racing tires to keep their competitors from duplicating them? This alone would make it real tough to be able to duplicate them. As to parameters for building a tire file, I think there should be as much information as possible put into the file to ensure that the tire will react as expected. The lack of transparency when it comes to testing might be an issue though. Perhaps ISI will release a tool for creating tires that will allow near real performance when done with their tool, or perhaps they will just supply the tires for the modders, who knows The fact that it was easier to create tires in rF1 suggests that perhaps they needed to update the way things were done to get a more realistic result as well as to make the tires work correctly with the game engine and their physics. I am hoping that they use the F2 driver to test the results of their tires as well as the car itself to be fairly certain that the car handles in all aspects like the real one.