Checking wheel offset...

I am considering changing alloys. I currently have Sport Design 18" alloys although the outer polished rim needs a refurb (maybe be selling them soon if any interest). My understanding is that they are: 8J 50ET front 10J 65ET rear Is this correct? If so, 8J 47ET front 10J 65ET rear from a 997 C2 only pushes out the front 3mm, which is a bonus - although only based on the above data. Any help really appreciated.

Hope this helps a little http://www.911uk.com/viewtopic.php?t=17331

Thank you I am not 100% sure it was not your thread that I gleaned the original offsets from. I think my logic is therefore right assuming these are the same on my C2 and therefore the Carrera 18" wheels will fit OK.

Just tidied up the thread

I had quite a lengthy thread on this previously and a "summary" of my findings are below.... The specification for 996 wheels are: (Summer tyres) Front = 8J x 18H2 - 50/52mm offset Rear = 10J x 18H2 - 65mm offset - or - (Winter tyres) Front = 8J x 18H2 - 50/52mm offset (or 7.5J x 18H2 - 50mm) Rear = 10J x 18H2 - 65mm offset The 996 was never tested or designed for 19" wheels. 18" is the biggest wheel that Porsche provided. Wheel options (all 18", ie. 18H2) Carrera wheels = 8J 50 / 10J 65 Turbo Look II = 8J 50 / 10J 65 Sport Design = 8J 52 / 10J 65 GT3 = 8J 52 / 11J 63 SportTechno = 8J 50 / 11J 63 Carrera, Turbo II and SportDesign wheels are approved fitment for Carrera 2/4 + Targa only (ie. not wide bodied 996) and are compatible with 5mm spacers (part 000.044.500.09) You get 4*5mm spacers in this part pack and they come with longer bolts (and locking wheel nut). GT3 and SportTechno are also approved for the narrow-bodied 996, but not with the 5mm spacer option. GT3 and SportTechno wheels are also approved fitment for Turbo, Turbo S and C4S in conjunction with 17mm spacers on rear axel (part 000.044.500.10). You get 2*17mm spacers in this part pack and they come with longer bolts (and locking wheel nut). Now that said, I have definitely seen Turbo II wheels on a C4S and Turbo, so I don't understand the Tequipment comment above, as they would have been shipped from the factory like this (so probably compatible with 17mm spacers as well). Alternatively, all I can think of is that there's different ET values for the Turbo II wheels depending on whether they are for narrow or wide bodied cars, but I can't believe that's true? With the spacers in mind, this would widen the track slightly and would take them beyond the specification of the 997 wheels you list above (if I understand correctly, you subtract the 5mm spacer from the original offset?, ie. 50-5 = 45???). I might be wrong on this, but the spacer will definitely push the wheels further out from the car. However, Porsche OPC **definitely** do not recommend or approve 997 wheels on a 996 and I am certain this would be an isssue if you have suspension (or associated faults) and tried to claim under warranty. My Conclusion: 996 and 997 wheels are different for a reason (and I am sure it's not because Dr Porsche wants to stop people putting 997 wheels on a 996 car, otherwise he would have used another method) and although they feel fine and I am sure that the car will drive normally, I would not be comfortable driving my car on the limit and would be worried about the potential damage to the track and geo. However, I know people in this forum have done exactly this, with no reported problems (eg. the 997 Turbo wheel on a 996 Turbo). I personally wouldn't recommend this unless the wheel model and specification is identical. One other problem, is that OPC aren't buying 996 wheels anymore, so they are very low on stock. I was going to buy some brand new Carrera wheels (with tyres), for 2 reasons: 1) I can't find any for sale secondhand 2) Even if I could, I would be concerned about any damage or repair that had been concealed....and I would be confident doing 150mph on secondhand wheels (unless I new the history of the wheels and trusted the seller). ....but they don't have any in stock any more!!!! You can still get them from places like Design911, but they are £1500 and then you have to buy tyres as well. OPC would have sold them for £2500, including tyres. At the moment, I'm considering GT3 wheels, which they still stock, but I don't want my car to look as though I'm trying to pretend I have a GT3 (which isn't the case, otherwise I would have bought one). Cheers, GD References: Guildford OPC (and confirmed with Mid-Sussex OPC) Official Porsche Manual Tequipment Brochure

Excellent - many thanks - then the only discernable difference between the current Sport Design 18s and the Carrera III wheels is a 3mm offset change on the front and I was toying with 5mm spacers on the GT3s anyway! The wheels I am about to collect are brand new 997 wheels with tyres for a lot less than the OPC wanted so no damage worries at all....

996 front wheels were mostly 7.5J width, not the 8J mentioned. The 8J width Sport Design wheels were first intended on the Mk1 GT3, although they can fit other 996s no problem. Chauch, are you still selling your wheels? If so, I might have interest depending on their condition. Please drop me a PM with the info.

No problem at all. It was a good opportunity to post this all in a single thread, as this has been discussed on the forum lots of times, but not in a single thread. Do you mind my asking how much you are paying for the wheels and tyres? If the wheels and tyres are affectively brand new, then I guess around 1200-1500 is a fair price (at least from my experience). It's interesting that you can getting rid of the split rim Sport Design wheels. These were a very popular option when new, but loads of people are now getting rid of these....I would guess for the following reasons: 1) Split rims are difficult to get refurbished (only a few specialists do this) 2) They are difficult to keep clean The Turbo II (twist) are also starting to appear, but I think (and this is only my opinion) that they are starting to look a bit dated as they originally came out on the 993 and the 1996 Boxster. The Carrera wheel is still an option on the 997 and suits the 996 perfectly. The GT3 is also a very nice wheel, but requires a bit more cleaning effort!!

PS - Can you please let me know where you found this from (from your 997 wheel): 8J 47ET front 10J 65ET rear I haven't been able to find the specification of the 997 wheels and would be interested to add it this thread as a reference.

> 996 front wheels were mostly 7.5J width, not the 8J mentioned. It's very interesting that you say this. All new 996 wheels are definitely 8J width on the front, not 7.5J. This is stated in a number of official Porsche documentation, including the manual and tequipment. You can also see this on the design911.co.uk genuine Porsche wheels page. 7.5J (front) and 9J (rear) is the specification for Boxster 986 wheels. HOWEVER, the reason why I am very interested in your comment is that I've noticed that a lot of 2nd hand wheels that are coming up for sale (off the 996..as stated by the seller) have a front offset of 7.5J, not 8J. It's usually the Turbo twist wheel and I see these on eBay and Pistonheads. I can only surmise that these are from the 1998-2002 models. Anything after 2003 seems to have 8J on the front. I have definitely seen an advert from a facelifted 2002 that has 7.5J specification on the front. I don't know why it changed, but would be very interested to understand why Porsche did this. Has something in the geo changed in 2003? I know that the MOST connection changed (and the CDR-22 stereo to CDR-23 accordingly), so I'm wondering if there were a some other changes to the 2003 model that we aren't aware of? 2004 changed to 2 year servicing, so I suspect something did happen in 2003 as well.

The seller read the 47ET from the alloy but I am collecting later so will confirm 100%. I managed to get them for £870! I will also verify the offsets etc of the current wheels. I have had a few enquiries about the Sport Designs already via PM and the honest answer is that I have not given much thought to a price - any views? The centres are in very good shape, the polished outer rims certainly need a refurb, they have gold crested centres. They have Continental Sport Contacts - N rated - all round 225/40/18 front with between 3.5 - 5mm tread 265/35/18 rear with between 5-6mm tread left The wheels are only about 3 years old and supplied by an OPC.

Sorry, I should have clarified earlier: Yes, I was referring to the pre-facelift 996 which came with 7.5J width as standard as the wheels in question were the Sport Design wheels. The Sport Design wheels were released for the pre-facelift Boxster/996, not the facelift 996. The facelift 996 had 8J as standard (5 spoke Carreras standard)

Have the rims been diamond cut before?

My facelifted 996 came with 17" wheels as standard unfortunately! I've always had 18" or 19" wheels on my previous cars, so (to me at least!) my car looks like it has more rubber than alloy!!!! I've only ever seen one other 996 facelift with 17" wheels, so I'm fairly sure everyone else upgraded theirs to 18"!!!! Apart from Jasmine Porsche, 911uk.com, Pistonheads and eBay, does anyone know of any other good sources for **used** genuine Porsche alloys please? I've been searching on Google, but can't find anywhere (except breakers).

Erm, I thought the facelift 996 came with 18" wheels as standard from the factory. Did you buy your car new or used?