Having the correct wheel offset and backspace is paramount not only to the performance of your vehicle but to the overall appearance of your car or truck! We’ve all seen those Mustangs or other cars where the wheels are sunk into the wheel wells, looking like spare tires on all 4 corners. Nobody wants that. We’ve also seen cars with what appears to be wide wheels installed when in reality the wheel and tire combo just has the wrong specs!
When you follow manufacturers’ specifications on offset and backspacing, you can have improved handling, less stress on suspension components and even wider wheel widths can be installed for the highly sought after staggered look on your Ford Mustang or other vehicles!
The offset of a wheel is the distance from the hub mounting surface (where the wheel bolts to the car) to the centerline of the wheel By centerline of the wheel we mean that if you were to split the width of the wheel in half, it would be directly in the middle of the barrel of the wheel. (See photos below). This is an important measurement to keep an eye on when choosing your next set of Mustang wheels. The wheel offset is measured in millimeters and is calculated in three different ways:
The backspacing is measured from the back portion of the wheel to the hub surface of the wheel where it bolts to the car. Backspacing is always measured in inches and is closely related to the offset, meaning, when you change one it immediately affects the other.
This is extremely important because it determines the distance between the wheel and the wheel well. This dimension also will directly affect how much the wheel will stick out past the fender or how far the wheel will sink into the fender well. You can measure a wheel’s backspacing by running a straight edge across the wheel bead and dropping another straight edge down to the wheel face, Then grab a measuring tape and measure the distance. This may be easier performed with two rulers.
The bolt pattern is the diameter of the circle made by the centers of your Mustang's wheel lugs. Ford used a number of different options with offset and backspacing over the years depending on the year and model of their longest-running pony car! The list below will cover the details and differences of the wheel offset and backspacing, as well as wheel size, stud size, and center bore.
|Year||Stock Wheel Size||Stock Bolt Pattern||Stud Size||Center Bore||Offset|
|1979-1993 Mustang||14-16"||4"x108mm||1/2"x20mm||63.4||15-25mm (M)|
|1985-1993 Mustang GT||15-16"||4"x108mm||1/2"x20mm||63.4||15-25mm (M)|
|1994-1998 Mustang, GT & Cobra||15-18"||5"x114.3mm||1/2"x20mm||70.3||35-50mm (H)|
|1999-2004 Mustang, GT & Cobra||15-18"||5"x114.3mm||1/2"x20mm||70.3||35-50mm (H)|
|2005-2009 Mustang & Mustang GT||16-18"||5"x114.3mm||1/2"x20mm||70.3||35-50mm (H)|
|2010-2014 Mustang & Mustang GT||17-19"||5"x114.3mm||1/2"x20mm||70.3||35-50mm (H)|
|2015-2021 Mustang, GT, Ecoboost||17-20"||5"x114.3mm||1/2"x14mm||70.3||35-50mm (H)|
Having the correct knowledge before you purchase aftermarket wheels for your car can save you not only money but will save valuable time and reduce frustration! Though this article highlights the Ford Mustang, anyone can learn from this priceless content when upgrading your car or truck!
As always, for more informative automotive articles, keep it here with the real Mustang enthusiasts, LMR.com!