Mustang Wheel Backspacing and Offset Explained

Mustang Wheel Backspacing and Offset Explained

Last Updated October 18, 2021 | Meghan Drummond
Contents

To pick the right set of wheels and tires for your Mustang, you should know about wheel offset and backspacing. These two measurements affect wheel fitment as much as the diameter. Two wheels with the same diameter, but with a different offset and backspacing, will fit differently. While one may be a perfect fit, the other could rub against the fender or the suspension.

Here’s everything you need to know about offset and backspacing so you can pick the right rims for your Mustang.

What Is Wheel Offset?

Wheel offset is the distance, measured in millimeters, from the hub to the wheel’s centerline. Offset can be positive, negative, or zero.

Three images showing positive, zero, and negative offset

  • Positive offset wheels have their hub mounting surface towards the outer rim of the wheel. This is the setup found on most OEM rides.

    Positive offset creates a lot of clearance between the tire’s edge and fender. That also means there’s less clearance between the inside of the wheel and the shock or strut. Too much positive offset can result in poor handling and make your car unstable.
  • Zero offset wheels have the hub mounting surface even with the wheel’s centerline. That means there will be equal distance on either side.
  • Negative offset wheels have a deep concave look. The hub mounting surface is towards the inside of the wheel. This creates a flush look with your tires and fenders. Deep dish wheels are popular for this look.

    Too much negative offset can put a lot of stress on your suspension. It can also cause steering wheel kickback.

What Is Wheel Backspacing?

Wheel backspacing is the distance, usually measured in inches, from the wheel’s hub to the back of its surface. You need enough backspace for your brakes and suspension.

Less backspace means that you’ll have plenty of space for your brakes and suspension. But, with too little backspace wheels can look sunken and skinny.

Having more backspace means there’s more wheel after the mounting surface. Having too much backspace could cause your tires to rub against the wheel wells.

Mustang Wheel Offset Chart

A good starting point for figuring out a suitable offset and backspacing for your wheels is the equipment they came stock with. Here are the stock measurements for Mustangs.

Mustang Stock Wheel Offset and Measurements
Mustang Year and ModelOffsetCenter BoreStock Wheel SizeStud SizeBolt Pattern
1979-1993 Mustang 15-25mm 63.4mm 14-16” ½” x 20mm 4 x 108mm
1994-2004 Mustang 35-50mm 70.3mm 15-18” ½” x 20mm 5 x 114.3mm
2005-2009 Mustang 35-50mm 70.6mm 16-18” ½” x 20mm 5 x 114.3mm
2010-2014 Mustang 35-50mm 70.6mm 17-19” ½” x 20mm 5 x 114.3mm
2015-2021 Mustang 35-52.5mm 70.5mm 17-20” ½” x 14mm 5 x 114.3mm

Measuring Backspacing and Offset

If you’re not running stock wheels on your Mustang, or you want to double-check your offset for accuracy, you can measure backspacing and offset yourself. You’ll want to start with backspacing and then move on to offset.

How to Measure Backspacing

Picture of how to measure backspace

  1. Lay the wheel down on a table or flat surface.
  2. Lay a ruler, or any other straight object, across the top of the wheel.
  3. Put the tape measure on the wheel’s hub.
  4. The distance between the hub and flat surface is the backspacing.

If you already know the offset, you can also calculate backspace using a formula. Note that the formula accounts for adding one inch to the wheel diameter since that’s usually the measurement from bead-to-bead instead of from the outer surface.

[(Wheel width + 1)/2] + [Offset/25.4 (to convert mm to inches)] = Backspacing

Here’s an example using an 11” wheel with a 50mm offset.

[(11” + 1)/2] + [50mm/25.4]

6” + 1.97” = 7.97” Backspace

How to Measure Wheel Offset

wheel with backspace, dead center, and front marked

  1. Lay the wheel on the ground.
  2. Measure the overall width of the wheel (not just the two flanges).
  3. Divide the width in half to find the centerline. Subtract the centerline from the backspace to find the offset.

The measurements you’ll get from the steps above can be plugged into this formula to get your offset. You can also skip the measuring step if you already know the backspacing and centerline measurements for the wheels you’re looking at.

(Wheel backspacing - centerline) x 25.4 (to convert inches to mm) = Offset

Here’s an example using the same 11” wheel from our backspacing equation. Its overall width would be 12”, the centerline is 6”, and the backspacing is 7.97.”

(7.97” - 6”) x 25.4 = 1.97” x 25.4

1.97” x 25.4 = 50.038 or 50 mm Offset

Wheel Offset and Backspacing Chart

If you’re not measuring a specific wheel, you can just look at hypotheticals. Here’s a table that can tell you offset based on rim width and backspacing.

Offset Chart Based on Rim Width and Backspacing
Backspacing ➡
Rim Width ⬇
3.25”3.5”3.754.0”4.25”4.5”4.75”5.0”5.25”5.5”5.75”6.0”6.25”6.5”6.75”7.0”7.25”
5.5” 0mm +6mm +12mm +19mm +25mm +32mm +38mm +44mm +51mm +57mm
6.0” -6mm 0mm +6mm +12mm +19mm +25mm +32mm +38mm +44mm +51mm +57mm
6.5” -12mm -6mm 0mm +6mm +12mm +19mm +25mm +32mm +38mm +44mm +51mm +57mm
7.0” -19mm -12mm -6mm 0mm +6mm +12mm +19mm +25mm +32mm +38mm +44mm +51mm +57mm
7.5” -25mm -19mm -12mm -6mm 0mm +6mm +12mm +19mm +25mm +32mm +38mm +44mm +51mm +57mm
8.0” -32mm -25mm -19mm -12mm -6mm 0mm +6mm +12mm +19mm +25mm +32mm +38mm +44mm +51mm +57mm
8.5” -38mm -32mm -25mm -19mm -12mm -6mm 0mm +6mm +12mm +19mm +25mm +32mm +38mm +44mm +51mm +57mm
9.0” -44mm -38mm -32mm -25mm -19mm -12mm -6mm 0mm +6mm +12mm +19mm +25mm +32mm +38mm +44mm +51mm +57mm
9.5” -51mm -44mm -38mm -32mm -25mm -19mm -12mm -6mm 0mm +6mm +12mm +19mm +25mm +32mm +38mm +44mm +51mm
10.0” -57mm -51mm -44mm -38mm -32mm -25mm -19mm -12mm -6mm 0mm +6mm +12mm +19mm +25mm +32mm +38mm +44mm
10.5” -63mm -57mm -51mm -44mm -38mm -32mm -25mm -19mm -12mm -6mm 0mm +6mm +12mm +19mm +25mm +32mm +44mm
11.0” -70mm -63mm -57mm -51mm -44mm -38mm -32mm -25mm -19mm -12mm -6mm 0mm +6mm +12mm +19mm +25mm +32mm
11.5” -76mm -70mm -63mm -57mm -51mm -44mm -38mm -32mm -25mm -19mm -12mm -6mm 0mm +6mm +12mm +19mm +25mm
12.0” -83mm -76mm -70mm -63mm -57mm -51mm -44mm -38mm -32mm -25mm -19mm -12mm -6mm 0mm +6mm +12mm +19mm
14.0” -102mm -95mm -89mm -83mm -76mm -70mm -63mm -57mm -51mm -44mm -38mm -32mm -25mm -19mm -12mm -6mm
16.0” -102mm -95mm -89mm -83mm -76mm -70mm -63mm -57mm -44mm -38mm -32mm -25mm
18” -102mm -95mm -89mm -83mm -76mm -70mm -63mm -57mm

Finding the Best Wheels for Your Mustang

Getting the right set of aftermarket wheels can make your Mustang build shine. By knowing the backspacing and offset ahead of time, you can rest easy knowing there’s plenty of space for your suspension and braking components and that your tires won’t rub.

With Mustangs, you have a lot of options for wheels. Many people decide to get a positive offset and have a large backspace so they can equip a big brake kit. Others decide to go for a set of deep dish wheels to get a look that’s aggressive and stylish. Check out our generation-specific wheel and tire guides for more inspiration.

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About the Author

Meghan is a Classic Mustang geek with a soft spot for four-eyed Foxes. She has over 300 in-depth articles to her credit that have been cited by some of the top news sites in the US. Read full bio →

This article was researched, written, edited, and reviewed following the steps outlined in our editorial process. Learn more about CJ's editorial standards and guidelines.

Mustang Wheel Backspacing and Offset Explained

Just as important to wheel fitment as diameter is the offset and backspacing. Here’s what to know about these two measurements, what each generation of Mustang came stock with, and how to measure your own.