<VV> Backspace vs. offset

[Sethracer at aol.com]

In a message dated 8/7/2012 5:51:41 P.M. Pacific Daylight Time,  
joel at joelsplace.com writes:

Is that  3 1/2" including the rim thickness or just the actual inside 
offset  width?  Officially it shouldn't include the rim thickness so we have to  
deal with the differences between steel and aluminum wheels with the same  
offset.  One thing I haven't looked as since I haven't tried any 14"  wheels 
is the point of interference difference between 14 and 15"  wheels.  Do 14" 
wheels have more room at the steering arm than  15"?
Joel



Backspace is independent of wheel material. It is the distance from  the 
mounting face of the wheel to the furthest (farthest?) most edge of the  wheel 
rim. Of course rims have different profiles in that area. The inside of  
the mounting point for the tire is used in calculating wheel width, because  
wheel width is measured where the tire mounts, not on the outside of the rim. 
 Offset is a calculated number, backspace can be measured.
Seth  Emerson

C's the Day! - Corvair,  Camaro, Corvette

San Jose, CA