Simulating Car Tires on a Surface

Hello, I need a bit of advice, I want to simulate a car on top of a steel plate, I need to add the force normal to the plate face, I also know that I need to make the 4 tires areas that are in contact with the plate, to add the force on Inventor Stress simulation I need to just add the forces in those areas only, for doing that I need to split the face, but should I just do it on top of the plate or also on the bottom?

What about if I do the same but instead of using a plate I use a tube?

Do I need to split the top face or all the faces?

Thanks

Split only the faces where the force is applied.

Thanks JD!