Widest rear WHEEL fitment

[Audio]

I apologize if this has been answered in the past, but I only did a fairly quick search.

I am not asking what the widest tire I can fit on a stock wheel, I'm not talking about rolling fenders or stretching tires. I'm not talking about poking out the side of the car, or any of that silly stuff.

Simply put: To stay within the factory wheel arches, what offeset/width will fit on the rear without interfering with any components? For example: On my old mustang, there was minimal modification to fit 10.5" wheels with 315s or 325s, and zero modification to fit 9.5" wheels and 285s etc.

(This is for a 2009 4.6)

Thank you for any information!

 

[Audio]

It appears I MAY have found the answer.
Anyone correct me if I'm wrong, but using a 20" wheel as an example, the size I could fit in the rear is 20x9.5 with a 275/40/20 tires and the calculator(not specific to the car though), says ET24 for that wheel setup, to get as close as possible to stock overall diameter and go as wide as will fit.

Now, does anyone know if that offset would produce any issues with hitting the lip of the wheel arch?

 

[Ambush]

Hey
I am no expert but from learning on this board, you can really go with 20x10 in the rear with 275/35/20 (I dont think 40 would work), the offset that I understand would be 40+ in the rear.

Just my 2 cents.

 

[Audio]

From what I've looked at on tire diameter calculators, 275/40 would be a lot closer to stock diameter than 275/35. If I ever replace the wheels, I can see myself getting 19's anyway. I've never been into the huge wheel thing, but it's a big car so really 19-20 looks right at home.

 

[dareckibmw]

@Ambush is right.

What are the specs of your OEM wheels/tires?

NVM...I think I found it.

I'm sure 10's will fit in just fine with a correct offset, which should be 40+

 

[Audio]

I like how detailed that calculator is, darekibmw! What site is that from?

 

[xiaphin]

I like how detailed that calculator is, darekibmw! What site is that from?

http://www.willtheyfit.com/

FWIW, I'm running 10.5+28 with 235/35/20 but on air and has slight poke at lowered ride height. My 10+18 fit in rear and don't poke.