I am extremely confused regarding this topic.
I understand that a wheels offset is determined by the space between the face of the rotor and the hub of the wheel. this also determines the size of the "lip" a wheel has. the lower the offset , the less clearance between the wheel and rotor, right? heres where I become confused:
A spacer should increase between a wheel and rotor-hence the name- but why does it decrease offset length (therefore logically increasing more space)?
I am trying to figure this out b/c I probably have this all backwards.
Also, why must offset increase if a wheel gets wider.
Lastly, can the offset of the wheel be grinded down to clear or allow proper fitment on a s2000.

Any clarification on this issue will be greatly appreciated.

 

http://www.tirerack.com/wheels/tech/offset.jsp

This will show you the basics of wheel tech.

 

that link isnt detailed enough. sorry, but I am still confused.

 

Your understanding of how an offset is calculated is not correct.........



The offset is the distance in millimeters between the centerline of the wheel and the mounting surface........the picture shows a "positive" offset.

If the centerline of the wheel is always 1/2 of the wheel width........then that can never change.........center is center. Centerline of an 8" wheel....4"...........a 9" wheel would be 4.5" and so on.

Some manufactures offer different offsets so their wheels can fit propperly on different cars without being tucked to far inside the fender well.........or hanging to far outside the fenderwell.

 

please explain more.

 

I am always utterly amazed that the effect of changing offset on steering geometry is ALWAYS ignored, and this car is supposed to be bought for its handling!

If the offset is reduced (so the wheel now sticks out of the wheel well more) this can overload the wheelbearings and produce unpleasant steering kickback. In the event of tyre failure, it increases the wrenching on the steering as it increses the leverage. VW used to go for a heavy offset so that their cars had more straight-line stability in such a case or in slippery conditions.

I guess for many people, cosmetic is everything and handling/ride/longevity mattes not a jot.

 

WHO KNOWS THE ANSWER TO THIS: What is the offset on the STOCK wheels??? I need to know this to compare to the Volks I just bought!

 

I'm confused man...............what exactly are you not getting....

Did you look at the diagram above....?? Did you stop & think about it for a minute...???

If the centerline of a wheel is always 1/2 of the width......and that can never change regardless of the wheel width........

What does change / can change according on how you want the wheel to fit your car is the offset.....which is directly related to the distance from the mounting surface....to the centerline in mm.

For Example: Lets say that the wheel pictured above is an 18" x 8" with a +45 offset.

If you took the same wheel......with the same diameter (18")....and the same width (8")......but you changed the offset to a +35. The centerline does not change......wheel width does not change.........the distance between the mounting surface and the centerline does change.........it got smaller by 10 mm.....the result would push the "Street Side" edge of the wheel outward toward the fendwerwell.

Taking the same 18" x 8" wheel and changing the offset to a +55 would have the opposite effect......the distance from the centerline to the mounting surface would increase by 10 mm.......resulting in the wheel tucking inside the fenderwell

Running a wheel with to low of an offset combined with a wide tire width are what causes common rubbing issues on the S2000.

 

excellent explanation Babtite
You done good!!

 

Stock offsets for 2000-2003 are:

Front: 55mm
Rear: 65mm

I think they are the same for 2004-2005.