Eyeman

What is up with our front splines being bigger than on other Porsche? My first set of aftermarket wheels somewhat bumped into the spline even though the wheel dealer swore they would fit. I just bought some Volk Porsche wheels off Ebay and they really don't fit. What bore is required for our fronts? Do any other Porsche have similar issues. I'm sure I'll be able to have these wheels modified to fit, but is there any way to change our front wheel setup to fix this bore issue?

The rears seem to fit fine but can someone tell me what are the three flanges that stick out a little in the center of our rear hubs? These wheels seem to poke out less than my first aftermarket wheels, which is good, those wheels did not fit well. I do not know the offsets of those. These are 18x10et50 rears, 18x8.5et50 fronts.

Btw, I completely understand offsets. I have a BMW with Volk wheels so I've heard it tons of times that you "don't put Japanese wheels on a German car", "those wheels are too big", etc. I'm into wheels, especially polished lip TE/LE37 Volks, which is what these are. This is also not my collector car. On it I plan I am staying as stock as possible.

oz968

Its more about the thickness that the mounting hub needs to be as the bearing carrier extends out as part of the hub.
If you alter the existing CB and get it made larger to allow the wheel to bolt flat on the top hat/hub then you cant get your wheel centre cap on as the bearing dust cap sticks thru the centre to far
A lot of guys use a spacer to create the thickness required
example a +45 offset is required for the fronts so buy a +35 offset and use a 10mm spacer (71.6 centre bore) problem is that you will then need to use longer wheel studs or buy spacers which bolt to the existing stock top hat and then have studs as part of the set up

Eyeman

Thanks for the help. I understand all that. My fronts are 8.5inches wide, et50. I'd need a 15mm or maybe even larger spacer to clear my barrier carrier. As you know, that would stick my wheel out way too far.

The things I still don't understand is do other Porsche not have bearing carriers that extend out so far? How is center bore for a wheel specified? The main center bore in my wheel is around 71.5mm which seems to be what Porsche need. But as you are saying the part for the center cap is what is narrowing the bore. So would my wheels have a center bore of 71.5 or the 61.5 of the area for the center cap? Or maybe someone has modified the thickness of the mounting hubs on these wheels to somewhat make them et50,and that's why I'm having this issue?

I plan to remove this center cap area and if I can not figure out a more flat mount center cap, then I don't really mind. Many prefer the track look of Volks without center caps.

oz968

not sure about other Porsche models but encountered same on my Andy Keel blown 928

Boeing 717

Have you found a hub centric spacer that will fit on front? I've tried two and neither will fit over the bearing cap.

Eyeman

With these wheels I need to go the other way, expand the bore. I guess that's what you'd have to do with hubcentric spacers, have them rebored.

Boeing 717

Best I can tell, you lose the lip that makes them hubcentric if you do that.

oz968

So on the wheels I just put on my car the rears were fine but the fronts needed a 5mm spacer as they wouldn't butt up against the top hat and the bore is 71.5 or 71.6 what ever it is so I didn't want to open the bore up any further as the wheel centre cap would not go on any way so I needed a 5mm spacer and with the 45 offset the 5mm made it a 50mm offset which filled the guard beautifully.

But you are in trouble with a 50mm offset as if you space it out it will sit outside the guard line but if you open the bore up you will not get the wheel centre cap on...my advise is start again and get a 45 offset with a 5mm spacer dependant upon how thick the hub of the rim is.

When you look at the OEM rims the hubs thickness is really thick to suit the extended carrier for the wheel on this particular model.

peter

Eyeman

Yep, that's what happened with my first aftermarket wheels. I had my spacer machined down not sure how small, either 2 or 3 mm, the center cap sorta poked forward but still went on. That was until a tire shop decided that they always try wheels without spacers first and they finished busting out the center of one of my wheels.

I am not switching wheels. I give similar advice to those looking at wheels that don't fit. You have to decide if the wheel is worth the effort.