Offset question

[89325iturbo]

What offset is needed for a 15x8" to stick out the same as a 15x10" et0? I was thinking a 15x8" et-25. Does this sound right?

[Zic]

changing the width x amount only changes the centerline x/2 which is where offset is measured from. all you ever need to know:

+1" lip = -12.7mm offset
+.5" lip = -6.35mm offset
-.5" lip = +6.35mm offset
-1" lip = +12.7mm offset

+1" barrel = +12.7mm offset
+.5" barrel = +6.35mm offset
-.5" barrel = -6.35mm offset
-1" barrel = -12.7mm offset

et.-25 should be bang on the money.