Offset help?

2013Zsport

Thanks! I think the sport wheels are 19x9f +47 245/40/19 & 19x10r +30 275/35/19 at least 09-12 my13tires are the same maybe the offsets are different, I'll see if I can find anything on that.

cooltoy

Same numbers I have seen. Like I said - not sure about 2013-14.

Anyway here as some numbers with different tire options and offsets. I ran your desired offsets and getyuorwheels recommendations. The difference in tire numbers is obviously by how much the tire sticks out past the lip.

Fronts:

255/35/20x9 +30
Will stick out 22 mm farther then stock.
Wheel diameter 686 mm (679 mm stock)
245/35/20x9 +30
Will stick out 17 mm farther then stock.
Wheel diameter 680 mm (679 mm stock)

255/35/20x9 +20
Will stick out 32 mm farther then stock.
Wheel diameter 686 mm (679 mm stock)
245/35/20x9 +20
Will stick out 27 mm farther then stock.
Wheel diameter 680 mm (679 mm stock)

Rear:

285/30/20x11 +28
Will stick out 7 mm farther then stock.
Wheel diameter 680 mm (675 mm stock)
295/30/20x11 +28
Will stick out 12 mm farther then stock.
Wheel diameter 686 mm (679 mm stock)
305/30/20x11 +28
Will stick out 17 mm farther then stock.
Wheel diameter 692 mm (679 mm stock)

285/30/20x11 +15
Will stick out 20 mm farther then stock.
Wheel diameter 680 mm (675 mm stock)
295/30/20x11 +15
Will stick out 25 mm farther then stock.
Wheel diameter 686 mm (675 mm stock)
305/30/20x11 +15
Will stick out 30 mm farther then stock.
Wheel diameter 692 mm (675 mm stock)

285/30/20x11 +23
Will stick out 12 mm farther then stock.
Wheel diameter 680 mm (675 mm stock)
295/30/20x11 +23
Will stick out 17 mm farther then stock.
Wheel diameter 686 mm (675 mm stock)
305/30/20x11 +23
Will stick out 22 mm farther then stock.
Wheel diameter 692 mm (675 mm stock)

Hope this helps.

2013Zsport

it does help thanks! i just got off the phone with Forgestar and they recommended 20x9.5F +25 with a 255/35/20 and a 20x11R +20 with a 295 or 305 tire. I'm still going with a 285 though