DougM

Here is a basic visual to help
--- is rim width
| is back of rim that mounts to car hub
et is offset in mm. 25.4mm=1 inch

------|------ 0 et offset with equal frontspace and backspace or "0"et
-------|----- + et offset with more BS and less FS or +et
-----|------- - et offset with less BS and more FS or -et

negative offset give a very deep dish wheel
more positive offset pushes the center section toward the outside of the rim.
Spacers add to the negative offset..... a 10mm spacer takes et 50 to et40.

If you add overall width to your wheels... going from a 8" wheel to a 10" wheel, you will add 1" frontspace and 1" backspace assuming the offset is the same. The offset simply pushes the barrel of the rim in or out. The width splits both front and back space.

rgs944

It's pretty easy to do and IMHO improves the looks of the car quite a bit. The main thing is to make sure the paint is very warm and you go just a little bit at a time.

Fnic99

Thanks, I had the negative and positive backwards. Still would like to hear the size spacer people used with the same combo.

9x8

You don't need the spacer with ET41.
I ran 295/30 on 18/11ET65 with a 15mm spacer on my GT (effectively bringing the ET to 50), it fit perfectly. Although GT has factory rolled fender lips, - and, besides that, fenders might've been pulled a bit by previous owners.

Also, you can't really go with more offset than ~ET50-ET55 for 18/11 rims, because you will hit the inside of the wheel well. Every car is a bit different, but It really should not be the case with ET41 - therefore no need for spacer.

If possible, try to test fit a rim alone and look at the tolerances.