Is my math correct: wheel offsets

[jul654321]

First of all, hello everybody here, this is my first "technical" post here, wheel offsets are the devil !

I have 7" wide, ET 23.3 phone dials wheels on the 85.5 944, front and rears.

Thinking of replacing them by 7.5" ET 52 front and 9" ET 47 back.

If I use a ~20mm spacer in the front, and nothing in the back, will everything be ok ?
I'm a bit afraid of the 50mm "extra" wheel on the rear, should I use a spacer on the rears too, and move the wheel out a bit more ?

Sorry for the xxxxth question on wheel offsets, but as they say, better safe than sorry !

Thanks for the help !

[Rasta Monsta]

Call Dave at Porsche Wheels, Tires and Accessories. He can answer your questions and sell you the spacers as well.

[racer]

Sounds like you have an "early" car and want to fit "late" wheels.

So.. you need a spacer to go from 52 et minus 23mm et and from 47mm et to a 23mm et so... you need 29mm front and 24mm spacer rear. They neededn't be perfect, though, since as you look at the 944 fenders, there is quite a bit of room.

1" is about 25.4mm

This "upgrade" has been done many times.

Offset (ET) is the difference between the mounting face of the wheel and the actual wheel centerline.