996 alloy fitment, offsets etc - Help please!

[thegoose]

I posted this in another thread but I think the question got lost in there. Many thanks in anticipation.

dom9 said:

They are lovely with the gold centres...

I know, I'm very tempted to get the gold centred ones.

So, who can tell me whether 8J et42 + 10J et47 will fit a narrow bodied C2?

Car is lowered on TechArt (I think) springs and dampers.

It's currently got 5mm front and 15mm rear spacers and the 17" genuine winter wheels are 7J ET50 and 9J ET55 and fit fine, although I think the fronts should be spaced out further really (summers are 18" turbo looks but might be replicas - no numbers by valves, and are in the shed at the moment).

I've tried using this: http://www.1010tires.com/Tools/Wheel-Offset-Calcul... but due to the spacers and wider rim widths (i.e. I don't know what clearance space there's likely to be on the inside) I'm still unsure if they'll work. It looks like the rears will stick out too much with the current rear spacers, but doing away with those and putting the (current front) 5mm ones on the rear and none on the front might come close to fitting OK?

[nxi20]

For the fronts, you'll have 10mm less inside clearance & 16mm more on the outside.

On the rear, you'll have 20mm less inside clearance & 6mm more on the outside.

HTH

ETA: That's without using any spacers on the new wheels, btw.

[thegoose]

nxi20 said:

For the fronts, you'll have 10mm less inside clearance & 16mm more on the outside.

On the rear, you'll have 20mm less inside clearance & 6mm more on the outside.

HTH

ETA: That's without using any spacers on the new wheels, btw.

Do you mean less outside clearance, rather than more? The way it reads is that the fronts will be 6mm narrower than standard and the rears 14mm wider than standard - can't be right, surely?

Can you tell me the usual sizes for 18" standard Porsche genuine wheels, all I've had to go on is the 17" sizes and offsets?

[Magic919]

My C2 996 was 8 wide at front with 50 offset. Rear was 10 with 65 offset.

[smj996c]

thegoose said:

nxi20 said:

For the fronts, you'll have 10mm less inside clearance & 16mm more on the outside.

On the rear, you'll have 20mm less inside clearance & 6mm more on the outside.

HTH

ETA: That's without using any spacers on the new wheels, btw.

Do you mean less outside clearance, rather than more? The way it reads is that the fronts will be 6mm narrower than standard and the rears 14mm wider than standard - can't be right, surely?

Can you tell me the usual sizes for 18" standard Porsche genuine wheels, all I've had to go on is the 17" sizes and offsets?

Marcus, have a look here

http://www.944racing.de/wheelweights.php

im pretty sure a NB 996 offsets are ET50 front and ET65 rear.

[thegoose]

So the rears being a 47 instead of 65 will stick out 18mm further, take away the 15mm spacer and they're pretty close to being bang on (sticking out an extra 3mm), although the arches may need rolling, and the fronts being 42 instead of 52 will stick out an extra 10mm, which it looks like it can easily handle, but there's still the option of removing the 5mm spacers.

I'm going to double check the rear spacer thickness and then it might be time to get my cheque book out.

Does anybody want to buy some recently (under 1,000 miles) stripped and powder coated refurbished Turbo 1 look 18" wheels?

[nxi20]

thegoose said:

Do you mean less outside clearance, rather than more? The way it reads is that the fronts will be 6mm narrower than standard and the rears 14mm wider than standard - can't be right, surely?

Can you tell me the usual sizes for 18" standard Porsche genuine wheels, all I've had to go on is the 17" sizes and offsets?

Sorry Marcus, it made perfect sense to me when I wrote it but you're right, it really doesn't


What it means is it sticks out more on the outside, so you have less clearance to the arch. The overall numbers add up to 26mm extra at each end because you're adding an inch to the wheel width.

This is the definitive info I have on 996 wheels:

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.

[thegoose]

nxi20 said:

helpful stuff

So, from that, would you agree with my post above yours that these wheels I'm looking at will fit the way I've suggested (ignoring Porsche approval, simply based on what will fit)?

[_gez_]

thegoose said:

So, who can tell me whether 8J et42 + 10J et47 will fit a narrow bodied C2?



It's currently got 5mm front and 15mm rear spacers and the 17" genuine winter wheels are 7J ET50 and 9J ET55 and fit fine, although I think the fronts should be spaced out further really (summers are 18" turbo looks but might be replicas - no numbers by valves, and are in the shed at the moment).

I've tried using this: http://www.1010tires.com/Tools/Wheel-Offset-Calcul...

The spacers with your current wheels effectively make them 7J et45 at the front and 9J et40 at the rear.

So over to 1010tires and you get the following results for the new wheels without spacers.

Front


Rear

[nxi20]

thegoose said:

So, from that, would you agree with my post above yours that these wheels I'm looking at will fit the way I've suggested (ignoring Porsche approval, simply based on what will fit)?

Yes, they should fit just fine. IME, it's the clearance on the front strut which is often the problem area, but there's plenty of extra room to fit a 5mm or even 10mm spacer if you need to.

[DiscoColin]

nxi20 said:

GT3 = 8J 52 / 11J 63

Not quite - you have a gen 1 front and a gen 2 rear there. The Sportdesigns on a 996.1 GT3 are 18x8 ET52 and 18x10 ET65 (plus a 5mm spacer on the front IIRC). It also comes in 7.5 and 9 for Boxsters.
On a 996.2 GT3 they are 18x8.5 ET40 and 18x11 ET63, though the same design wheel is also available in 18x8 ET50, 18x11 ET45 and 18x12 ET45 for Turbos and GT2s.

[Dammit]

Bumping an old, old thread here - is there now a definitive "these are the widths and offsets that go under a 996.1" statement?

I'm considering BBS LM's, which can be had in either 10", 50ET or 11", 56ET. The 11's would protrude 22mm beyond where my current 10" 65ET wheels do (according to the calculator linked above).

[Slippydiff]

The 11’s will fit depending on what ride height, tyres and camber you run.
If you go 295 or wider, with square shoulders, lowered with stock camber settings, the arches will need rolling as the Mk1 seems to have a large/deep return on the inside of its rear quarter panels.

11 ET56 (IIRC) LM’s on my old CS. Suspension height was stock, ditto camber, tyres were round shouldered and hopeless Pirelli’s Corsas.