Wheel offset questions for custom wheels

[Teej281]

Hey all,
Been looking at ditching the 18x9/10.5 AFS Replicas recently for a new set of wheels. Been looking at the custom side and have found a set of wheels that I really like, through a company called Forgestar. The wheels I'm looking at are going to be 18x9.5 up front and 18x11 rears. The odd thing is the company does not advertise any backspacing sizes anywhere, but they have a wide range of offsets for each size of wheel. So here is where I need some help.

Now the front wheels, in 18x9.5, have offset options of +26 to +60. I think I'm right in saying that the +26 offset would be the right offset for the front of our cars with a normal backspacing of something close to 6" or so, correct?

Now the main question here is to figure out what the offset needs to be for the rear wheels. The 18x11 wheel size has options from +23 to +55. And if I'm not mistaken, the rear wheels should be something like +20 or so, right? What rear offset would I want then? With a backspacing that is normally like 6.5-7" backspacing, you would want like +20 offset?

Teej

 

[SpectorV]

you can figure out the backspacing/frontspacing by the offset (+/- etc you can figure it out if you know the wheel width)

for the front of and 03/04 you want the frontspacing (width - backspacing) to be... cant recall what mine are but the lower the car is the more the rim sits in vs out~ keep that in mind, probably around 2.89-3.11 inches.

For the rear the frontspacing needs to be 3.75-4.00 (fender flush is 4.00 but will require rolling fender lip 3.5 to usually avoid rolling fenders on 03/04 cobras with IRS)

Mine are about 3.75 frontspacing in the rear for example... and I rubbed a TINY bit on the inner fender lip back edge on drivers side only... due to the spot I am going to have to cut/remove some material.... cant roll the very back corner easily.

 

[Teej281]

These wheels are concave wheels so number might not be the same as they would be for CCW's, but here are the numbers the Forgestar wheel guy gave to me

18x11 +28 offset
18x9 +20 offset

Those numbers seem right at all?

 

[Spitting Cobra]

They seem pretty close.
The 18x9 cobras are +26mm offset/6.11 backspacing and the 18x10.5 are +27mm offset/6.9 backspacing.

You going for the deep concave CF5 Wheels?