Help... Offsets are way too confusing
 

OK I'm looking at replacements and have become somewhat educated off the web on wheels for Porsche.

I have a 1983 944 (yea...poor man's model)... it is in mint shape with 63K original...metalic Sable Brown. The pattern is 5 x 130 and the front offset is 23, rear is 15. Original wheels were 15 x 6" I think.

The BBS wheels I had on the car appear to have been setup to match this offset...but maybe not in the same direction. The BBS wheels are 16 x 9" and there is a spacer being used on the rears which looks like it may be about 1" (25mm) thick. This is no doubt to move everthing "out" for clearance.

I'm looking at some tires off a 98 Porsche 911 Carrera. Original wheel specs were 5 x 130 pattern; 55mm offset. The wheels I'm looking at are 17 x 7" (fronts) and 17 x 9" (rears) all have a 55mm offset...

What do I need to fit these on the 944... or will they fit as is with the 25mm spacer... something tells me mu wheel studs are too short...I'm think I need to move these 911 wheels out more.

Help if you can

Technically you should only need a set of 28mm spacers.

The front and rear offsets of your car is 23mm. The only time the rear changed, was with wider wheels : Cookies all 4 are 23mm, Fuch 15x7's are 23mm, the 15x8 Fuchs are 10.6mm. The offset is directly related to the wheel width, so with the wider 8" Fuchs, they 'narrowed' the offset to give it a deep dish look, less offset means less backspacing.

Anyone else agree?
 

I haven't checked the front spacer yet... but assume that it may be a 28mm already...so I can go ahead and get the 911 wheels with 55mm offset?

Great...

Actually...... I take that back, and wished someone had corrected me.

The rear's are set up for a 10.6mm offset, but when there were cookie cutters or some PD's on it, they had spacers. The front is set up for a 23mm offset.

So, as long as you still have the cookie cutter rear spacers, you'll just need some 30mm spacers. If the rear spacers are removed, then you'll need 30mm front, and roughly 44mm in the rear.

I said 28mm all around earlier, bad math, but you would be fine most likely with +/- 4mm I'm sure.


You'll probably want to take those numbers to a mm to inch converter, as most of the spacers on eBay are sold by inches.