Cup1 Wheel Offset

[Porshaah]

Hi All

Never having seen an earlier 23mm vs 47mm offset wheel side by side for comparison, I was wondering where the offset is created? Is the back mounting surface or are the spoke face different for the same width rim?

TIA

[Bill Verburg]

Originally Posted by Porshaah

Hi All

Never having seen an earlier 23mm vs 47mm offset wheel side by side for comparison, I was wondering where the offset is created? Is the back mounting surface or are the spoke face different for the same width rim?

TIA

ET or offset is the distance from the wheel center line to the mounting face
+ means that the centerline is inboard of the mounting face
- means that the centerline is outboard of the mounting face
0 means that the centerline matches the mounting face

additionally the back side of the spokes and hub can be shaped differently to provide more or less brake room

for instance 911 7" Fuchs and 944 7" Fuchs have the same ET @23.3, meaning that the wheel centerline is 23.3mm inboard of the mounting face. But the 944 wheel has a center section that is shaped to provide considerably more room for bigger brakes.

When mounted on a car the only visual clue as to which wheel is used is seen at the bolt holes

[proporsche]

here is my front 8th offset

and rear 9th offset

[Porshaah]

I understand the concept, I'm just not familiar with how, specifically, the OEM/Factory Cup1 (i.e. not Fuchs, Cookie Cutter, Phone Dial etc. just to keep things simple and it's all I'm interested in) early and late wheel differ in appearance. In other words, do the spokes protrude further past the face of the rim on a 47 than a 23 ET of the same rim width?

Again
TIA

[uwanna]

Originally Posted by Porshaah

I understand the concept, I'm just not familiar with how, specifically, the OEM/Factory Cup1 (i.e. not Fuchs, Cookie Cutter, Phone Dial etc. just to keep things simple and it's all I'm interested in) early and late wheel differ in appearance. In other words, do the spokes protrude further past the face of the rim on a 47 than a 23 ET of the same rim width?

Again
TIA

The ET23 early offset repro Cup1 wheels and the 47ET wheels externally
look identical. The difference is looking from the rear of the wheel.
The ET23 has much longer protruding mounting surface whereas the ET47 wheel has an almost flat mounting surface. Ergo the difference in ET

[Porshaah]

Thank you Uwanna and all, for your responses.