Large wheel caps, smaller steel rims

Hey guys, I’ve seen many times that some VW drivers are riding steel wheels on your car, which are equipped with wheel caps that are a lot bigger than normal. That looks awesome, makes the tyre cross section smaller. Since nobody could tell me how exactly that goes I’ve always thought about it. I also think to have found a solution. : Of course I can’t say if this is the right way. I would be really grateful for information about my project. s all is wrong what I have written here! And if anyone has any idea, what should be taken for adcaps if you have 14 inch steel? Greetings Sven