[se7en]

Sorry, but i dont understand the concept of needing adapter's for aftermarket rims.

I keep getting mixed replies so im hoping for the right advise.

Im looking to buy some aftermarket rims for my soon to be SC LPE car. The problem i keep running into is fitment.
The tire i want to run are the Nitto's NT555R's 305/35/20 rear and 275/40/20 in the front.
The rim i think i need are 20x10.5 rear and 20x9 in the front. Im also about to purchase some Pedders CoilOvers and im worried about fitment.

I know that 11.5 is what would be perfect for the rear, but i think its already going to stick out to far in the rear anyways.

Different people have told me that i need adapters not matter what size or type of rim i get. Can someone please explain to me why i would need an adapter for any size rim?

Any advice would be appreciated!
Brandon