Offset Question

[GN18944]

Okay. Here is my dilemma. My car has Eibach springs and I just installed the Baer 2 inch drop spindles. The car looks great but the front tires rub on the outer edge on the inner fender. Currently the car has the aluminum repop stock looking wheels. I'm assuming the offset is the same as stock.. 0mm. If I get 16mm offset wheels, does that bring the tire in by 16mm's? Before I invest the money in new wheels and tires I just want to be sure I'm doing my math right. Any input is appreciated.

 

[TexasT]

These wheels you are running, have you measured the back space on them? I'm not real sure what you mean by zero offset. And then you talk of a 16mm offset. What is the size and backspace on those?
Lots of variables when it comes to wheels. Then you mount different tire brands and stuff rubs. Even with the same size, just like shoes, things fit different.

 

[GN18944]

These wheels you are running, have you measured the back space on them? I'm not real sure what you mean by zero offset. And then you talk of a 16mm offset. What is the size and backspace on those?
Lots of variables when it comes to wheels. Then you mount different tire brands and stuff rubs. Even with the same size, just like shoes, things fit different.

Thanks for the response.

http://www.gbodyparts.com/product_info.php?products_id=1642

These are the wheels on the car. I bought the car with them so I am not sure if the wheel is the 7 or the 8 inch wide. Not sure how to measure that with a tire mounted on it. My best guess is the 7in due to the fact that the rear is obviously wider, but definitely not a 10in.

 

[Turbo6inKY]

Offset is the difference between the location of the mounting pad and the center of the rim.
Backspace is the distance between the mounting pad and inside edge of the rim.

The only way to truly know what you have is to measure.

 

[1986 Buick GX1]

Offset is the difference between the location of the mounting pad and the center of the rim.
Backspace is the distance between the mounting pad and inside edge of the rim.

The only way to truly know what you have is to measure.

 

[GN18944]

View attachment 301802

This is what I believed it to be. So I pose the question. If the stock wheel is a 0mm offset, that means a 16mm offset will move the wheel in toward the center of the car by 16mm, correct?

If they are both 7 inch wide rims, the one with a 16mm offset will be 16mm closer to the center of the car from what I'm reading. Let me know if I am correct.

 

[TexasT]

Depends on if it is positive offset or negative offset as illustrated in the diagram above.

 

[1986 Buick GX1]

Depends on if it is positive offset or negative offset as illustrated in the diagram above.

This is what I believed it to be. So I pose the question. If the stock wheel is a 0mm offset, that means a 16mm offset will move the wheel in toward the center of the car by 16mm, correct?

If they are both 7 inch wide rims, the one with a 16mm offset will be 16mm closer to the center of the car from what I'm reading. Let me know if I am correct.

You are correct. A positive offset (+16mm offset) is more like a front drive and would be closer to the center of the car (sucked in).

I'm not sure why automakers started using offset because it seems to be a relative measurement and doesn't take into consideration the wheel lip thickness as does backspacing.
An 8" wheel is 8" on the inside of the lip where the tire contacts the wheel. Who cares where that point is? You want to measure from the axle flange/ hub to the inside edge of the wheel so it doesn't hit the frame.
Granted most wheel lips are 1/4- 3/8" thick, depending on the wheel manufacturing process.

When using offset I like to measure off the existing wheel for clearances.
I have to make a chart and plot different options out to keep track of things.

Example chart for my 2013 F**d Explorer.

 

[GN18944]

You are correct. A positive offset (+16mm offset) is more like a front drive and would be closer to the center of the car (sucked in).

I'm not sure why automakers started using offset because it seems to be a relative measurement and doesn't take into consideration the wheel lip thickness as does backspacing.
An 8" wheel is 8" on the inside of the lip where the tire contacts the wheel. Who cares where that point is? You want to measure from the axle flange/ hub to the inside edge of the wheel so it doesn't hit the frame.
Granted most wheel lips are 1/4- 3/8" thick, depending on the wheel manufacturing process.

When using offset I like to measure off the existing wheel for clearances.
I have to make a chart and plot different options out to keep track of things.

Example chart for my 2013 F**d Explorer.
View attachment 301833[/QUe

Explained well. Thank you.