With 17" wheels: 42 = rub if your lowered, 45 = rub if you are lowered alot with 7.5" wheel and min 215/45 tire, 48 = perfect pretty much always.
You can extrapolate what that will mean with your given wheel sizes. So if you plan on running an 18" wheel, you'll have to pick your tire size and check the overall width and diameter of that tire. Then compare it to the overall width and diameter of the tire I listed and you will pretty much have your answer as to what will happen. Most likely you wont be able to do anyting more than a 48"
Gun Metal is darker than Steel Grey. Steel Grey is slightly darker than silver.






Below are the few wheels in stock at Rota US that will fit the Focus. Apparently their inventory changes WEEKLY and some models/sizes/colors they don't have in stock all the time.
Linear Mode
