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Hey there, while I am waiting to send her in for paint I got it in my head I would fit Boxster S wheels to my car. One thing is I have always liked them and I have only seen these on one other 928, there are likely others.
Our stock wheels are 16x7 (front) et 65 on 225/50/16 tires and 16X8 (rear) et 52.3 on 245/45/16 tires
The Boxster S wheels are 17x7 (front) et 55 and 17X8.5 (rear) et 50
By my calculations I will need to run 225/45/17 (fronts) and 255/40/17 (rears). To even out the offsets I need to run 10mm spacers up front and maybe even 5mm in the rear which may be snug.
I did all my calculations here and some research on prior threads. Would appreciate any thoughts or guidance you all have.
Spacer wont work. You need a "Negative Wheel Spacer" which brings the wheels inward. The 10mm off the shelf spacer will simply make your wheels ET45. Wrong direction.
Myself, with the help of a few others here at RL, have developed the NWS which if installed (not easy) will get you back 11 to 16mm of offset so your ET55 wheels will become a near perfect ET66 to 71.
You can run the ET55's, it will be OK, might tramline a bit depending on the type of tire you run. A tire with an asymmetric tread pattern like a Conti DWS06 will help with tram.
You don't need any spacers, positive or negative. The Boxster wheel will work just fine, notwithstanding the negtive comments you might get from the guys who seem to be most concerened about the scrub rradius which I tihnk might be of concern at about 140 mph and maybe rough road surfaces. Your tire sizes are just fine, but I would put 255 45 17s on the rear. Just me. My advise it to go for it.!!!!
That 55 front offset is fine. Lots of us run 57 and that's only 2mm further out with your et55 wheels.
My rears are 10" wide et65 with a 10mm spacer, making it an et55. Your wheel is 1.5" narrower. If it had the same 55 net offset, that would mean the 1.5" difference gets divided evenly to the inside and outside, so 19mm further in on both sides, but your offset is et 50 so your outer weel edge will be 14mm further in than mine and the inner wheel edge 24mm further from the suspension.
They'll fit fine....the fronts will look perfect, the rears will look sunken in a bit. You might want a 10-15mm spacer for the rear.
09-21-2022, 03:32 PM
Boxster S Wheels on my Shark, Checking my Math
I appreciate your response, I will check this out. I was going to go with the Conti's so that affirms that decision. Thanks so much!
