what is 0mm in reference to offset/backspace?

[Red Regal T]

Window shopping wheels and was wondering what kind of backspace would a 17 X 8 wheel have if they list the offset as 0 mm? tia

 

[Mrhotwheels]

That would work great. The answer is 4"

 

[Steve Wood]

But measure them because it does not always seem to come out right when I figure the offset and then measure the back space...

In theory, offset is the distance that the mounting pad face is from the center of the wheel. Seems like my GTA wheels have 4 3/8s" bs but the offset is 0.

 

[Red Regal T]

Well, actually the wheels I'm looking at are aftermarket chrome IROC wheels, only in a 17, instead of a 16 X 8. I already have IROCs on my car and the backspace is the same as the GTAs. I really like the IROCs but they could be in better condition. If I go for the new IROCs, I won't have to worry about spending money on wheels I may decide I don't like and they are reasonably priced. You can view them at www.skperformance.com/WHEELS/DANTE.htm#chevy

THANKS FOR YOUR ANSWERS!

 

[PCS74]

When comparing backspacing to offset you have to figure in the difference the "lip" makes.

One of my friends has chrome 18" IROC copies(F-body), they are incredible looking wheels and IMO might be worth looking in to as they will fill the wheel well better than the 17's.


Chris S

 

[Red Regal T]

I guess 18" look good but then you get into a more expensive tire, no straightline traction, and a harder ride. 17s are big enough. Also, some people would like 20" better......it's all personal taste. The bigger the wheel gets, the more the car looks like it should drive in circles and let the 50 clowns jump out.

 

[stickybones]

Yes, you need to remember the thickness of the lip when comparing backspace and offset. For example, my GTA rims are 16x8, zero offset. But the backspace is 4.5" because if you measure the rim total width (outside edge to outside edge) it is 9" not 8". The 8" is where the bead of the tire would sit. The lip is 0.5" on each side giving the overall width of 9".

 

[Mrhotwheels]

Backspacing is not measured using the back edge of the wheel to the mounting flange. You lay something inside the bead and measure from the mounting flange to that.

 

[stickybones]

I think this is another topic where everyone does it a wee bit differently.

 

[John B]

Backspacing is not measured using the back edge of the wheel to the mounting flange. You lay something inside the bead and measure from the mounting flange to that.

Not True! Backspacing is measured from the outermost lip of the wheel. Typically an 8" wheel is ~9" wide overall lip to lip making the backspacing ~4.5" for zero offset as mentioned above.

 

[Mrhotwheels]

You can go to www.afswheels.com and click on the link that explains backspacing. They do it the same way I was taught.

 

[John B]

Mrhotwheels , not trying to flame you but you were taught incorrectly and AFS is "clueless" when it comes to measuring backspacing based on the pic they show. Backspacing is always measured to the lip of the wheel, not the bead...end of discussion. If you don't believe me (and you don't have to) just try any reputable tire shop like Discount Tire or the Tire Rack.

 

[Mrhotwheels]

Are they wrong here too?
www.thebensons.org/blkntan/backspacing.htm

 

[UNGN]

Originally posted by Mrhotwheels
Are they wrong here too?
www.thebensons.org/blkntan/backspacing.htm

No, backspacing is measured from the inside rim lip to the hub inside face (mounting flange), just like they show in drawing you posted.

Measuring the backside of the bead face isn't correct and throws another variable into a measurement that is already inconsistant between wheel types.

 

[John B]

Are they wrong here too?

Pay close attention to what you posted here about thebenson.org pic! If you notice carefully, the arrow points to the outer most portion of the lip....so yes, this pic is correct, just like I already stated!

 

[Mrhotwheels]

John, that picture is how I tried to describe measuring backspacing. Maybe you did not undertand me or I did not explain the directions properly in my original response. I guess that the top of the bead area would be flush with the back of the wheel. We would both use two different techniques to get the same results.

 

[John B]

Peace

 

[UNGN]

Originally posted by Mrhotwheels
I guess that the top of the bead area would be flush with the back of the wheel. We would both use two different techniques to get the same results.

The "Top of the Bead" and the "wheel lip" are usually not the same distance from the mounting flange. The AFS website clearly does not show the correct way to measure backspacing.