Wheel size and offset
04-10-2018, 09:16 PM
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Wheel size and offset
First off, I know the topic of wheel size has been discussed many times here, but I could not find exactly my situation so I apologize if it's out there somewhere.
The issue is this, I have a 91 Carerra 2 and I've got rubbing in the rear portion of the front fenders on both sides. When I bought the car it was and still is fitted with Cup Design 92's. I believe they are Mille Miglia replicas, I will put pictures of them below, if someone could confirm that I appreciate it. There is no Porsche part number anywhere on the wheel nor is the offset by the valve stem which could also indicate an OEM wheel I believe? Sizes are as follows:
Front
7 1/2J x 17 ET 52
Tires 205/50 ZR17
Rear
9J x 17 ET 47
Tires 255/40 ZR17
In reading Adrian Streather's book, he says any 7.5J wheel needs spacers. However the offsets he has for 7.5J's are 55 and 65 in which he says spacers required. Mine are marked ET 52. I also discovered the tech bulletin for the larger steering stops had not been done either. So first off I will do the steering stops, but are spacers necessary as well? If so what should I use a 3-5mm maybe? It also seems these wheels being 9's and 7.5's are different than what most have on their 964's. Any comments or opinions are appreciated. Also what should I spray in the wheel well to repair the rub marks and cover them up?
04-10-2018, 10:20 PM
#2
First off, I know the topic of wheel size has been discussed many times here, but I could not find exactly my situation so I apologize if it's out there somewhere.
The issue is this, I have a 91 Carerra 2 and I've got rubbing in the rear portion of the front fenders on both sides. When I bought the car it was and still is fitted with Cup Design 92's. I believe they are Mille Miglia replicas, I will put pictures of them below, if someone could confirm that I appreciate it. There is no Porsche part number anywhere on the wheel nor is the offset by the valve stem which could also indicate an OEM wheel I believe? Sizes are as follows:
Front
7 1/2J x 17 ET 52
Tires 205/50 ZR17
Rear
9J x 17 ET 47
Tires 255/40 ZR17
In reading Adrian Streather's book, he says any 7.5J wheel needs spacers. However the offsets he has for 7.5J's are 55 and 65 in which he says spacers required. Mine are marked ET 52. I also discovered the tech bulletin for the larger steering stops had not been done either. So first off I will do the steering stops, but are spacers necessary as well? If so what should I use a 3-5mm maybe? It also seems these wheels being 9's and 7.5's are different than what most have on their 964's. Any comments or opinions are appreciated. Also what should I spray in the wheel well to repair the rub marks and cover them up?
some models(RS) used 7.5ET55 which would extend ~.25" both inboard and outboard more than the 7
Where exactly is the rub? is it on the inner wall of the chassis?
similar situation in back, 8ET52 w/ 255/40 x17 was stock but 9ET55 w/ the same tires was fitted to some models(RS) your 9ET47 is slightly more aggressive, ~ .7" more front space and .3" more backspace than the 8s and ~.3" more front space & -.3" less backspace