Measurements for our wheels and how to measure.

[sleeperred90tgp]

Ok Kenny i pulled a wheel and measured it. I didn't believe the 25mm (1") backspace.  :icon_rolleyes:You can just look under the car at a wheel and see that its more than 25mm even though its been posted here several times. I guess the first incorrect post carried through.  :dunno:

Here's what we have.

Bolt pattern 5 x 115mm

Rim width 8" Inside bead to inside bead. Where the tire seals to the wheel.

Backspace 5 1/2" Back of wheel to mounting surface. Thats 139.7 mm.

Front spacing  3 5/8" Front of wheel to mounting surface

Wheel offset 1 13/16 Positive toward the front of the wheel. Distance from C/L to mounting surface.

Now I know what to look for. :icon_biggrin:

How to measure a rim.

Wheel Backspace
This is the distance from the back edge of the wheel to the hub mounting surface. To determine the wheel backspace:
Position the wheel face down.

Lay a straight-edge across the back of the wheel.
Measure the distance from the straight-edge to the wheel's hub mounting surface.

Wheel offset
The wheel's offset is the distance from its hub mounting surface to the centerline of the wheel. To determine wheel offset:
Position the wheel on a flat surface and measure its overall width.

Subtract the backspace and divide by two.
The offset of a wheel can be one of the following three settings:

Zero offset:
The hub mounting surface is even with the centerline of the wheel.

Positive offset:
The hub mounting surface is toward the front or wheel side of the wheel. Positive offset wheels are generally found on front-wheel drive cars.

Negative offset:
The hub mounting surface is toward the back or brake side of the wheel's centerline. "Deep dish" wheels are typically negative offset. 
 
 


Jud

[TGPilot]

I never knew nor did I ever try fitting wheels...but damn good to know. :icon_exclaim:

With you saying we have 1 13/16" offset that is 46.038mm offset right? That is damn close to 2x more! :icon_eek: I spoke to Shawn at W-body a while ago and I think he said he put 25mm offset wheels on his car and they were perfect. Would that just be that to the naked eye a less than 1" difference in offset isn't noticeable? :icon_confused: