what does positive offset mean versus negative?

the diagram on the tirerack site, is that an example of positive or negative?

my oem 16" wheel has an offset of 47mm, what would a 40mm offset do?

Originally Posted by Magna

the diagram on the tirerack site, is that an example of positive or negative?

my oem 16" wheel has an offset of 47mm, what would a 40mm offset do?

The diagram is an example of positive offset.

Your car has a positive offset wheel. That means that the center of the tire is more towards the center of the car than a zero offset wheel. If you went to a wheel with a 40mm positive offset, your tires would be 7mm more towards the outside of the car than your stock wheels. This generally makes it look like the tires and wheels fill in the fender wells more, and will probably have some slight effects on the handling. Also, tire size becomes more critical; you probably won't be able to use quite as wide of a tire as with the stock offset.

The above example is right if the wheels are the same width

In other words a 16" x 7" wheel with a 40 offset with be pushed out further then a 16" x 7" wheel with a 47 offset but if the width changes then you need to figure out the difference . . .

For example a 16" x 7" wheel with a 40 offset is not the same as a 16" x 8" wheel with a 40 offset . . . the 16" x 8" wheel will stick out approximately 12.5 millimeters more (a 1/2" ).


The offset is measured from the center of the wheel


EDIT: had equation incorrect, but is now correct . . .
Man does this get a little complicated ...

Originally Posted by AF330i

The above example is right if the wheels are the same width

In other words a 16" x 7" wheel with a 40 offset with be pushed out further then a 16" x 7" wheel with a 47 offset but if the width changes then you need to figure out the difference . . .

For example a 16" x 7" wheel with a 40 offset is not the same as a 16" x 8" wheel with a 40 offset . . . the 16" x 8" wheel will stick out approximately 12.5 millimeters more (a 1/2" ).


The offset is measured from the center of the wheel


EDIT: had equation incorrect, but is now correct . . .
Man does this get a little complicated ...

Good clarification. I didn't even consider the different width wheel issue.

Originally Posted by GregD

Good clarification. I didn't even consider the different width wheel issue.

Thanks . . . sometimes this gets so confusing

Originally Posted by AF330i

Thanks . . . sometimes this gets so confusing

Ah ok . . . starting to be more clear!! Thanks.

Now naturally I would want the offset to be as close to factory specs as possible. My OEM wheel has a offset of 47mm (style 54 wheels). On my snow tires the offset is 40mm. Is that difference significant?

Also what bad consequences are there having wheels not to factory specs?

Originally Posted by Magna

Ah ok . . . starting to be more clear!! Thanks.

Now naturally I would want the offset to be as close to factory specs as possible. My OEM wheel has a offset of 47mm (style 54 wheels). On my snow tires the offset is 40mm. Is that difference significant?

Also what bad consequences are there having wheels not to factory specs?

Can you tell us the exact size of your wheels both snow and OEM

You don't have to stay with the factory specs . . . there is actually a certain range you can stay within and have no problems at all . . .

Originally Posted by AF330i

Can you tell us the exact size of your wheels both snow and OEM

You don't have to stay with the factory specs . . . there is actually a certain range you can stay within and have no problems at all . . .

Sure . . . OEM= style 54 wheels (v-spoke) 16 x 7 with 225/50/16 tires

205/55/16 snows on Sport Edition TK5 wheels also 16 x 7

Originally Posted by Magna

Ah ok . . . starting to be more clear!! Thanks.

Now naturally I would want the offset to be as close to factory specs as possible. My OEM wheel has a offset of 47mm (style 54 wheels). On my snow tires the offset is 40mm. Is that difference significant?

Also what bad consequences are there having wheels not to factory specs?

I'd only be concerned if you plan on using chains. If so, you better check clearances very carefully.