CUP1 wheels on G-body

[avenbugt]

Does anyone have original cup(1) wheels on a 911 G-body? What size?
Maybe with picture?

[spuggy]

Original, or factory, Cup1 wheels are the wrong offset for G body cars, they're designed for ABS cars - eg 964 or later, 944/951 1987 and later etc. So they need spacers at least big enough to compensate for that.

I think ABS offsets are in the 50mm+ range, so probably need at least 30mm spacers.

Most, if not all, G bodies running Cup 1s are actually running replicas, produced by multiple manufacturers in multiple offsets - including the correct ones for G body cars to use without spacers. I have a set of Mille Miglia reps with Blizzaks mounted I use as winter wheels.

[Bill Verburg]

Originally Posted by avenbugt

Does anyone have original cup(1) wheels on a 911 G-body? What size?
Maybe with picture?

Cup1 from a 964 in 17
7ET55
7.5ET55
8ET52
9ET55
9.5ET68
There are other wheels like Cup Design'93 w/ somewhat different ETs
and also 16" Cup design
in 16
6ET52
8ET52

say you want 8ET52 & 9.5ET68 on an SC/Carrera
front you want 8ET27 so use 52-27 = 25mm spacers
back you want 9.5ET19, so use 68 - 19 = 49mm spacers

[Bill Douglas]

Don't be tempted to use the fakes. They are very heavy. They look great but are not good for performance.

[avenbugt]

Originally Posted by spuggy

Original, or factory, Cup1 wheels are the wrong offset for G body cars, they're designed for ABS cars - eg 964 or later, 944/951 1987 and later etc. So they need spacers at least big enough to compensate for that.

I think ABS offsets are in the 50mm+ range, so probably need at least 30mm spacers.

Most, if not all, G bodies running Cup 1s are actually running replicas, produced by multiple manufacturers in multiple offsets - including the correct ones for G body cars to use without spacers. I have a set of Mille Miglia reps with Blizzaks mounted I use as winter wheels.

Originally Posted by Bill Verburg

Cup1 from a 964 in 17
7ET55
7.5ET55
8ET52
9ET55
9.5ET68
There are other wheels like Cup Design'93 w/ somewhat different ETs
and also 16" Cup design
in 16
6ET52
8ET52

say you want 8ET52 & 9.5ET68 on an SC/Carrera
front you want 8ET27 so use 52-27 = 25mm spacers
back you want 9.5ET19, so use 68 - 19 = 49mm spacers

I have on my 79 G-body factory Cup1 9" and 7" with 4.5cm spacers rear and 1.5cm front

[Bill Verburg]

Originally Posted by avenbugt

I have on my 79 G-body factory Cup1 9" and 7" with 4.5cm spacers rear and 1.5cm front

great but what are the wheel ETs

if you have a 7ET55 w/ a 15mm spacer that is a 7ET 40, f/s is 58mm and b/s is 138mn. On a 911 front f/s max is ~89mm and max b/s is ~146mm, so yes yours fits after a fashion, but most would prefer the optics of a f/s closer to 89mm. I have 8s w/ f/s 85mm on mine

[faverymi]

Cup 1 replicas.
Early offset.
I think there is a set for sale here.
Awfully heavy. 4 corner anchors
No thanks.

[avenbugt]

Originally Posted by bill verburg

great but what are the wheel ets

et55

[avenbugt]

Originally Posted by Bill Verburg

great but what are the wheel ETs

... f/s is 58mm and b/s is 138mn. On a 911 front f/s max is ~89mm and max b/s is ~146mm,...

Maybe a stupid question, but what is "f/s and b/s"?

[Bill Verburg]

Originally Posted by avenbugt

Maybe a stupid question, but what is "f/s and b/s"?

f/s -front space
b/s -backspace

each wheel well has a defined space, length, width, height which accommodates the wheel/tire. f/s measures from the hub mounting face out and b/s from the hub face in.




f/s and b/s can be applied to the wheel, tire or the assembly

here is an analysis of a max 17 fitment on and SC/Carrera

f/s & b/s for wheel , nominal installed tire, actual installed tire are specified

The actual installed #s show what the max f/s and b/s will be w/o ride height restrictions, these show as bright red when at or past max, there is a little wiggle room for these but not much

[avenbugt]

Originally Posted by Bill Verburg

f/s -front space
b/s -backspace

...

Thank you!

[Bill Douglas]

Originally Posted by Bill Verburg

Ah ha, so THAT'S the difference between offset and backspace - thanks.