Lastest Update: See Article in Excellence (Feb 2012 issue) "Five Lugs or Bust" on sale Dec 27/11.
NEW: I just arranged a Rennlist Group Buy at SUNCOAST for anyone interested in doing the conversion, Call Ric Knab 877-923-1700.....see pricing on Post #91
NOTE FOR ALL:Conversion confirmed go to Post # 52 on page 4 ! ALSO NEW FINAL PHOTOS in Posts #62 and#63 on Page 5 - ENJOY!!!!
Additional Notes: Wheel and tire sizes, theoretical offsets for the CL to 5 lug conversion are precisely the same for 997.1 GT3/RS and 997.2 GT3/RS.
Note that the Gen 1 cars use a 5mm spacer in the rear, so the wheel offset on a narrow body for example, is actually 68mm, but stepped out to 63mm when combined with the spacer. If you are ordering new wheels just use the standard Gen2 narrow or widebody offsets as a guide. Offsets do not change as a result of the conversion.
For my narrow body conversion I used:
Forgeline GA3R wheels: 8.5x19et 51mm (-2mm from OEM) and 12x19et63mm (same as OEM).
Ok, as many of you already know I am not a big fan of the Porsche street-going centerlock wheel set up. While I believe the arrangement is a very slick piece of engineering and the OEM wheels are really quite cool, the additional time, effort, care, and special maintenance to keep them safe and working perfectly is not fitting well with my “track-rat” lifestyle. After well over 60 full wheel and tire changes (yep, all four wheels!), investing in the proper tools and an extra set of wheels, and following the past and current Porsche guidelines to the letter, I have had enough!!!!
It is interesting to note that the “Centerlock Wheel Failure” thread of early this week has had absolutely nothing to do with my decision. In fact, I have been working on a plan to convert my car back to a 5 lug configuration for a few months. Yep, I am going back to the old fashioned 5 lugs!!! Shameless Plug: “PM” me if you would like to purchase my perfect condition, narrow body GT3 OEM CL Wheels.
The good news is that I have cracked the case of the Porsche Centerlock to 5 lug conversion after quite a bit of research/detailed detective work and will test the procedure later next week. I will post photos of the procedure here in this Rennlist Forum as a “Public Service Announcement” for all to see. Special Thanks go to:
Steven Tory (“Trophy”), Pete Hitesman (“Savyboy”), John ? (911Slow), Jess Lattin (Porsche Master Tech), Ric Knab (Suncoast Porsche), and David Schardt (Forgeline).
If you have centerlock wheels on your car, don’t despair, this system works fine and Porsche will likely report on the one isolated failure, and hopefully the answer will show up on the “CL Failure” Rennlist thread. The 5 lug conversion described here will likely only be considered for those “track-rats” like myself who gobble up track events a rate of 10 or more days per year.
So without further ado, here is a listing and cost of the Porsche OEM parts required for the 5 lug conversion and brief description of the work that will need to be done.
997-341-605-01 WHEEL HUB, 2 required, $326.80ea (Suncoast)
999-053-054-06 WHEEL BEARING, 2 required, $88.70ea (Suncoast)
997-331-605-00 WHEEL HUB, 2 required, $ 359.32ea (Suncoast)
999-053-055-02 WHEEL BEARING, 2 required, $113.49ea (Suncoast)
Porsche Lug bolts, 20 required, $7.43ea (Suncoast)
Race Studs: $91/set and Nuts: $77 (2 sets, cone-type and rounded Porsche-Type, best to have both types)
(see Track Studs by APEX: http://www.race-studs.com/servlet/th...Nose%27/Detail
Total Parts cost with Race Stud upgrade: $1954.62
(Of course this does not include the cost of a new set of wheels,…..or the required labor!)
After my original research was complete I figured that one had to only switch out the Hubs and upgrade to race quality stubs/nuts for the perfect conversion as I found during my research that all nuts and axles are fully compatible. However, this was not exactly the case as it was pointed out by Steven Tory that the Hubs would need to be pressed out of the front and rear wheel carriers destroying the (perfectly good) wheel bearings in the process. Thus new wheel bearings are required all round. The reason for this is that the hubs (CL or 5 lug) fit in to the bearings with an “interference fit” and must be pressed in and out of place. The only bad news is that more labor is required to accomplish the conversion than originally thought, as one must remove the wheel carrier from the car to accomplish the R&R of the CL hub/bearing/5-lug hub. This work is likely best done by a Porsche Dealer as it requires a suitable hydraulic press and accompanying tools, as pointed out by Jess Lattin. Also, the bearings must be installed in the correct orientation, magnetic side in, but this can easily be determined with a paperclip.
Anyway, this is the route I plan to follow. I will report back soon with some comments and photos of the procedure. Hopefully, now there is an alternative to just complaining about the CL wheels, and that Porsche AG will take our opinions into account when designing the next 991 GT cars.
Please, how about a choice next time around?
PS. 911SLOW, can you -re-post the PET figures of the front and rear wheel carriers in this thread along with the associated parts and numbers, so the guys can see. Also, please up my "photo" upload albilities....I've got no space left and I will need some more. Thx!