another wheel fitment post.... haha! please help!

[2007GrandPrixGT]

[TD="class: xl7317959"]

[/TD]

Stock Wheels:
2007 Grand Prix GT SE, 3.8 Supereater.
225/55R17
Paired 18 Spoke w Open Lugs, Smoke Brilliant, Option P04
17x6.5 5-115 ((Offset.... No Clue!!!!!))

New Wheel Breakdown:
I want to run an 18 inch wheel, 8-9 inches wide preferably. The offset is where im stumped, because i dont have a stock rim offset im not sure how to calculate a good fit. The tire size im going with is 235/45R18 94W (Should i go 245/45R18?). Im not looking for something over the top and complicated, just chrome and a tad bit wider tire, and sized the same front to back.

 

[Fivefingerdeathpunch]

30-40 offset is good.

You need to run a 245/45/18 to be the same size as stock and not to mess with the speedo.

 

[Sandman]

^^^this

Though I'm running a 8.25" wheel at a 25mm offset.

 

[2007GrandPrixGT]

30-40 offset is good.

You need to run a 245/45/18 to be the same size as stock and not to mess with the speedo.

Well I want to keep the suspention bone stock, I'm not looking to make modifications i just dot have the time... I'm also ordering online to save some cash, so I want to make sure I'm not making returns left and right, so ill try 245/45R18