balefire

https://rennlist.com/forums/996-foru...eel-width.html

Hopefully my 2004 anniversary edition 911 arrives soon.
I intend to autocross it in SCCA A-stock.
It comes with 18x8 et 50 front / 18x10 et 65 rear.

What was the largest size (diameter and width) that could be ordered from factory?
GT3 18x8.5 et 40 legal for front? GT3 18x11 et 63 legal for rear?
What was the most aggresive offset that could be ordered from factory?

Thanks!

MechanicalEng

You can run any wheel as long as is the exact same diameter and width as the OEM that came with your car, the tire size is open so you can run anything you want. I would go with 245s up front and 285/295 at the back

Pzkw993

You're allowed five millimeters of offset difference in the SCCA.

There are a couple of SCCA people who get VERY picky about Porsche wheel options. For that reason, I wouldn't buy any size that doesn't appear in the brochure for that year's car. Some of those people are even Porsche owners. I went through untold drama a few years ago when I suggested running an 18x8 wheel on the front of a Boxster instead of an 18x7.5. There are people who ordered Boxsters with the 8-inch wheel but it wasn't in the brochure as a factory option.

00r101

Unfortunately the brochures often listed wheels that were not factory options installed at the factory. But instead they listed Tequipment wheels that were only available at the dealership. You do need to be very careful. What you want to get hold of is the US Porsche order guide for your year and model.

What you might want to look into is weather there was a factory 5mm spacer available for your car. If so then you can run that (on all 4 wheels) as well as the 1/4" offset allowance offered by SCCA.

ttreat

00r101, you may know better than me but my interpretation of the SCCA rules does not allow you spacers on factory wheels plus the 1/4" offset. I interpret the rules as saying that any combination of offset and spacers must be within 1/4" of the stock configuration. Here is the excerpt from the rules book

"13.4 WHEELS
Any type wheel may be used provided it complies with the following: it
is the same width and diameter as standard, and as installed (including
wheel spacers if applicable) it does not have an offset more than
+/- 0.25 inch from a standard wheel for the car. The resultant change in
track dimensions is allowed.
13. STOCK CATEGORY — 73
Wheel spacers are permitted, provided the resultant combination complies
with the offset requirements of this section. Wheel studs, lug nuts,
and/or bolt length may be changed."

sjfehr

When the SCCA rules say "it is the same width and diameter as standard", and 17x7 and 18x7.5" are OEM options, would a 17x7.5" wheel be legal? It's the same width as standard, and the same diameter as standard, despite not matching either OEM combination of the two. Is there any precedent for SCCA challenges on this?

00r101

Typically manufacturers do not offer wheel spacers as a factory option. But Porsche did and does. Since it is a factory option you are still allowed the 1/4" offset allowance. I have asked for a ruling on this and received it. However, you must use the actual factory spacers AND you must use them at all 4 corners.

00r101

No. That is a misinterpretation of the rules and would quickly result in a protest.

ttreat

"No. That is a misinterpretation of the rules and would quickly result in a protest. "

00r101, thanks for the clarification. With so many factory options Porshce makes the SCCA rules even more confusing.

Does anyone know why Porsche would off factory spacers? Have any other manufacturers ever done this? You would think if you wanted a wider track they would just sell an option for a wider wheel or a different offset.

00r101

The large number of factory options and the confusing and sometimes incomplete way that Porsche documents them is one reason why Porsches are often put in tough classes by SCCA. SCCA doesn't want some poorly documented uber optioned Porsches from stealing the whole show.

Factory spacers do several things for Porsche as a company. They are easy to manufacture. One part fits almost all Porsche models and for many model years. They are a huge profit item ($500 option, H & R sells similar 5mm kits for other cars at $260). Its cheaper to make spacers than to make two different width wheels.

balefire

My 2004 996 options guide / Tequipment brochure is in the mail, so I'll confirm the spacers / wheels soon.

Assuming I'm stuck with the stock wheel widths (18x8 F , 18x10 R) what are some good "cheap" "light weight" wheel options? I would prefer to find OEM takeoffs since they're usually pretty cheap...

OZ Alleggerita 17.8 lbs / 19.0 lbs
Porsche OEM 996 Carrera 5 spoke 20.5 lbs / 22.7 lbs
Porsche OEM 993 Turbo hollow 19.9 lbs / 23.3 lbs
Porsche OEM 996 GT3 front 18x8?
Enkei NT-03+M Rear xx / 21.0 lbs

Sources:
http://members.rennlist.com/911pcars/WheelWts.html
http://www.944racing.de/felgengewichte.php

PedalFaster

The Carrera 5-spokes were the lightest factory wheel available. They're a couple of pounds each heavier than the lightest custom wheels, but personally I wouldn't spend the extra bucks on custom wheels.

Beware the ubiquitous OEM replica wheels, which are all over eBay but are considerably heavier (and sometimes not even the right size).

00r101

[QUOTE=balefire;7569461]My 2004 996 options guide / Tequipment brochure is in the mail, so I'll confirm the spacers / wheels soon.

Beware the Tequipment guide. While they list only Porsche parts many of those parts were not available as factory options and therefore are not Stock class legal. The options guide for your year is another story. It should be good documentation for Stock class legality issues. Remember though, that you must install all parts from an options package not just some (unless that part was also available as a standalone option).

jmazz

Follow up to this question... Can you run a rear wheel in the front? I never thought it would be legal but just read a post by someone that appears to be running a square setup in an SCCA stock class.

PedalFaster

No, you can't run rear wheels in the front unless cars came from the factory that way. My guess is that the person running a "square" setup is referring to tire sizes, not wheel sizes.