gab997

I have been looking at the classic from ccw 17x11, 17x9 or 9.5's. Do you have any good picts? Also, what is the difference with offsets compared to back spacing?

JackOlsen

Well, 'stupid' is probably overstating it. I'm sure it would be fine for street use. On a track, I think you'd have some high-speed push issues with that combo. But I've always tried to stay close to 90% for the f/r difference, like 205/225 225/245 255/275. I can't see the benefit with 335s in the back with anything skinnier than a 295 in front.



This diagram is from our local Rennlist/Pelican wheel expert, Bill Verburg.

Backspace is the measurement from the inside (car side) edge of the rim to the mounting surface of the wheel. Offset is the measurement of the distance from the wheel's centerline to the mounting surface. Offset can be positive or negative, depending on how 'deep' the rims are. With the 964 and later, the wheels on Porsches lost a lot of that 'deep dish' depth because the hubs mounting surface got moved farther outboard.

gab997

Thanks for the info Jack exactly what I was looking for.

purplehaze.

Thanks Jack.

Following that logic, if I used equal sized tires f/r the thing would probably not turn in as well. A slightly skinnier front actually helps turn in, if I understand you correctly. Hadn't thought of it like that.

It's mostly a track car, as the 275 fronts don't allow easy K-turns or similar. Not so much.

Thanks,

purplehaze.

Forgot to give you more pics/info on the CCW's on 930's -

When their server is back up again, try here:

http://forums.pelicanparts.com/showthread.php?t=425218

SleepRM3

Same question for me except I have an '88 Carrera modified for driver education events. It's a track car that's "streetable". I currently have 8 wides front, 9 wides rear with 225/45-17 front and 255/40-17 rear tires. I was hoping to stay with the same tire sizes, but increase wheel widths to 8.5 to 9s front and 9.5 to 10s rears. I just bought the car, and don't know the offsets. The car comes with Rufs for the street and Kinesis for the track. Street tires are AD07s and track tires are BFG G-Force R1s.

ivangene

I suggest a few events under your belt as it is, then make changes - just my opinion

SleepRM3

Yes that is a great suggestion. Just looking ahead. I might not need to change anything, as the previous owner had the car set up beautifully for his driving skills (he's club-raced/DE'd longer than I have).

altonj

On your car you are looking at 8.0 fronts with a 30 (ish) mm offset and 9.0-9.5 rears with 15-19mm offset. Depends alot on the camber you want to run. You can run a 225 front easy with a 255 rear or 235 front with the 255 rear or with a little work a 245 front and a 275 rear. However the 275 is a bit tall and has a negative effect on gearing.....

The above is under the assumption you are interested in 17 or 18 inch wheels.....

SleepRM3

Hi, thanks for the tip on wheel widths and offsets. Doesn't look like I can improve on my current setup, as I have 8 wides with 225/45-17 fronts and 9 wides with 255/40-17s rears. Camber is -1.2 fronts, -1.5 rears.