What offset do I need?

[Bo]

I'm thinking of buying a set of 993 or 993 Turbo wheels for my car, but since the car is fairly new to me, I have no clue of what offset on the wheels I should be on the lookout for.
What I'm thinking of is a set of 7.5" and 9" 17".

IS ET55 what I should look for? (for a stock 86 Carrera)

[Tim L]

23 mm front 15-18 mm rear these are the off sets I have used on an 84 with those rim widths. I run 225 - 255 with no rubbing but I did roll the front fenders. I think 17 mm rear is optimum.

Tim

[Bo]

How does that translate into the "ET"-numbers I see everywhere?
Is that a european-measurement only?

[Tim L]

It's the same thing I think.

Tim

[JeremyD]

Here's an excellent resource for offsets/weights and part#'s
http://members.rennlist.org/911pcars/WheelWts.html

Later wheels on an earlier car require spacers - typically 1" on the front - 2" on the rear - Your numbers may vary.