Maybe we can get this sticky, as the question comes up from time to time...
I put together an excel file plotting the offset of a wheel by width and backspace ranging from 5.5" to 14" wide (1/2" increments) and 3.25" to 7.5" backspacing (1/4" increments). So, if you know the width (*advertised) and the backspace, you can find the corresponding offset. Or, if you know the wheel width (*advertised) and the offset, you can find the corresponding backspace.
The used this formula in excel if anyone's interested in fumbling around with it on their own.
=CONVERT(((WHEEL_WIDTH+1)/2-WHEEL_BACKSPACE)*-1,"in","mm")
**there is a difference between a wheel's advertised width and it's actual measured width. Wheel manufacturers don't include a wheel's bead width, which is 1/2" per inner and outer tire bead, resulting in a 1" wider, by measurement, wheel. Be weary when purchasing wheels second-hand! If the seller measured by hand, instead of reading the casting marks, then things could get jumbled/confused. I used the advertised width for the calculations in the chart.
I put together an excel file plotting the offset of a wheel by width and backspace ranging from 5.5" to 14" wide (1/2" increments) and 3.25" to 7.5" backspacing (1/4" increments). So, if you know the width (*advertised) and the backspace, you can find the corresponding offset. Or, if you know the wheel width (*advertised) and the offset, you can find the corresponding backspace.
The used this formula in excel if anyone's interested in fumbling around with it on their own.
=CONVERT(((WHEEL_WIDTH+1)/2-WHEEL_BACKSPACE)*-1,"in","mm")
**there is a difference between a wheel's advertised width and it's actual measured width. Wheel manufacturers don't include a wheel's bead width, which is 1/2" per inner and outer tire bead, resulting in a 1" wider, by measurement, wheel. Be weary when purchasing wheels second-hand! If the seller measured by hand, instead of reading the casting marks, then things could get jumbled/confused. I used the advertised width for the calculations in the chart.
