Mustang Wheel Backspacing and Offset Explained

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.

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.

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.

• 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 the 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.

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

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 the 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

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.

Finding the Best Wheels for Your Mustang

Getting the right type 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 tire size will fit the wheel.

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.

Mustang Wheel and Tire Guides

Fox Body Wheel and Tire Guide

If you’re wondering what wheels and tires your Fox Body Mustang originally came with or what size you can upgrade to, this guide will walk you through wheel and tire selection.

SN95 Mustang Wheel Guide

Adding new wheels to your 1994-2004 Mustang will make a big difference in terms of style. Check out this guide for an overview of some of the best rims for your ride.

S197 Mustang Wheel Guide

For enthusiasts looking to customize the look of their S197 Mustang, a new set of wheels makes a big impact. Plus, upgrading to a larger size allows you to fit performance tires.

S550 Mustang Wheel & Tire Guide

There are tons of wheel and tire options for S550 Mustangs. Black and bronze wheels are a few of the hottest colors from popular brands like Velgen and Ford Performance.