New Wheels / Offset & Other info

[lap]

I was considering getting for my 02 Targa some HRE 543's (18") and wanted to know how wide can I go for Front / Back, in Wheel Width / Tire Size / & Proper Offsets.

PS> I am going to most likely upgrade to a PSS-9 system in the future as well.

TIA

lap

[Loren]

Here are the Porsche approved tires:

Tire Size

Front: 225/40 ZR 18

Rear: 285/30 ZR 18

Tires:

- Bridgestone Potenza S-02A N3 Directional

- Continental Sport Contact 2 N2 Side-directional

- Michelin Pilot Sport N1 Directional

- Pirelli P-ZERO ROSSO N4 Side-directional

Approved 18 wheels (w/offsets) are:

- Front: 8J X 18 offset - 50.0/52.0

- Rear: 10J X 18 offset - 65.0

5 mm spacers are approved on all four wheels.

17 mm spacers on the rear wheels and 5 mm spacers on the front are also approved with use of proper (longer) wheel bolts.

"Unofficially"

With the 8" front wheel you can go 235/40 ZR 18 tire without any rubbing and it will reduce understeer a little. A couple of brands of 295/30 ZR 18 rear tires are reported to not rub (or require fender rolling) but I can't recommend any especially if you are lowering the car.

Perhaps you can tell if this is a street car or track car and others can recommend tire/wheel combinations for both.

[lap]

Thanks Loren!

Some additional points:

1. 2002 Targa = Primarily Street Car (for SPIRITED DRIVING) & some track

2. OFFSETS: you mentioned: ... Approved 18 wheels (w/offsets) are: Front: 8J X 18 offset - "50.0/52.0" is that a range? Also, if 5mm spacers are "allowed" in the front, cannot I get that "built into" the wheel (Fr and Rr) from HRE? I don't think I want to risk the 235's up front unless I know for certain that I will not have "rubbing", BUT I definitely want to reduce understeer.

Right now my 1989 speedster w/ Koni Yellows feels much MORE connected, I know they are completely different creatures but I would like to get that same feeling in the newer car.

TIA!

[Loren]

All the Porsche OEM wheels are either 50 mm or 52 mm offset. I don't see any reason why you can't get the 5 mm offset built into the wheels (as long as it is correct).

I don't think the 235s will rub even with the 5 mm spacers. The fronts rub first on the inside -- and only 245s rub a little at lock to lock.

[lap]

Ok Loren,

Just so I don't screw this up,

1. what are the exact #'s to give HRE (w/ the most agressive offset built in, i.e. no extra spacers required)

2. 235's will work w/out rubbing? b/c you indicated "the fronts rub on the inside"??

THANKS AGAIN!

[GreggT]

Also, if 5mm spacers are "allowed" in the front, cannot I get that "built into" the wheel (Fr and Rr) from HRE?

LAP

One of the good things about buying custom wheels, is that you select the offset. If someone has a OE Carrera style wheels (which have 52 & 65mm offsets F/R) and they throw a 7mm spacer on the front and a 17mm on the rear, then they have an affective offset of 45 & 48.

Offset (or ET, which means 'pushed in') is decreased as you 'space' the wheel out.

Personally, I'd say there's nothing wrong w/OE tire sizes (shoot, the Turbo runs 225s in the front). If all you're after is good looking relationship of fender-to-rim (and not concerned about any of the possible negatives that go with it) then your car can handle the offset I described above (with 8J & 10J rims and OE rubber) even if the car is 'somewhat' lowered.

Here's a pic of same.....good luck.

[testdrv321]

I run 245's up front without any problems. Some negative camber may be required. I have almost -2 in the front, not sure what would happen with less.

[gry]

1999 C4 Cab

Would these RIMs fit on my car?

Front ET50 18x8 w/ Tires 225-40

Rear ET45 18x11 w/ no tires

According to Loren's post above, these rears seem too big?

How about these?

18" Porsche Turbo Staggered Wheels

18 x 10" Rear Wheels, offset ET40

18 x 8" Front Wheels, offset ET52

Porsche part #'s 893.362.140.00 and 893.362.136.00

What does the J stand for in Loren's post?

Where can I find out the best offset for my 99 C4 Cab? These are 5, 45, 40, and 52 but I'm new to this and don't know where I can reference the best offset for my car.

Thanks again for all the help!

Edited March 8, 2004 by gry