What are Wheel Offset and Backspacing?

Custom wheels are an affordable and simple way to add style to your vehicle. And changing wheel size or how they sit in the well involves specifications like wheel offset and backspacing. Wheel offset measures the clearance between your hub mounting surface and the wheel's centerline in millimeters, giving you an accurate representation of where your wheels will sit. And backspacing shows the distance from the back lip to the wheel mounting. You can see it clearly in the diagram below.

While backspacing can only be bigger or smaller, the offset has three distinct types:

1. Positive offset

The offset is considered positive when the hub mounting is closer to the outer side and away from the wheel's centerline. This type of offset creates a lot of backspacing and the wheel looks like it was sunk deep inside the car body.

2. Zero offset

Zero offset happens when the hub mounting aligns with the centerline. It is neutral, and the wheels neither look tucked in nor protruding out.

3. Negative offset

A negative offset is the opposite of a positive. It means that the mounting is in front of the centerline and it does not reach it. This keeps backspacing at a minimum. And the wheels stand out on either side of the car.

Each type of offset has its limitations and benefits. Some are purely cosmetic, but sometimes they can affect handling and steering too.

How to Understand the Difference Between Wheel Offset and Backspacing?

Both these specs are crucial when you customize wheels. Wheel offset has two major effects: how the wheel fits and how the vehicle performance changes. The first one is obvious. The wheel must fit inside the well to not damage the tire or other components like the car fender, for instance. Depending on your driving style and preferences, the second effect can be either a curse or a blessing.

Backspacing has less influence on the way your car behaves on the road, but it is still important to keep this in mind for safety reasons. Backspacing is basically the indication of how much of the wheel envelopes the mounting and deep it goes inside the well from the hub. This is crucial to know because you need to have enough clearance to protect elements like brake calipers and the car body from the rotating wheel. Less backspacing means the wheel is pushed further out and there is more space to fit those elements. And by increasing backspacing, you can actually make room for larger upgrades.

Maintaining a healthy balance between custom offset and backspacing is essential for a good result. If you have to sacrifice one for the other, then the wheel size you chose is not the optimal option for this particular car. Some changes can be made, of course, but it is much cheaper and easier to just downsize on the wheels instead.

Common Issues with Wheel Offset and Backspacing

Offset and backspacing must be carefully calculated beforehand. The wrong size and a few extra millimeters can ruin your wheels or damage the car's body. Friction heats up the rubber and causes it to deteriorate faster. This can eventually lead to bursting.

And backspacing can be tricky too. If there is too much backspacing, it can threaten not only the wheel integrity. When the vehicle makes turns, the inner edge of the wheel can come into contact with other elements of brakes, suspension and car body and damage them.

Another thing to consider is handling. A custom offset can make the vehicle feel different. For some drivers, this change is irrelevant, but if you prefer your car to drive in a particular way, maybe drastic offset changes are not for you.

Customizing with Wheel Offset and Backspacing

Car manufacturers have their own vision of what their models should look like and how they should behave. Most cars have some room for improvement. However, the space manufacturers leave for larger wheels and tires is often not enough to fit anything really different.

In contrast, the aftermarket often offers wheels with less backspacing and reduced offset. This helps fit larger tires for off-roading, increased stability and heavy-duty tasks. And, of course, massive and aggressive look.

The positive offset is the least favorable for customization. Unless you are looking for a way to tuck in the wheels, this type of offset has little more to offer. It is also not suitable for stancing your car.

Optimizing Performance with Wheel Offset and Backspacing

While there are a few pros of going for custom offset and backspacing, there are also some downsides to consider. One such drawback is an increased turning radius for negative offset. This can put you at a disadvantage at some tight turns. So do not go too heavy-handedly on the customization.

Lower offset and backspacing can put more strain on lugs and studs (bolts). This can compromise the car's wheels. And it also weighs down on the bearings and axles a bit more than it was meant to by the manufacturers.

How to Calculate Wheel Offset and Backspacing for Your Vehicle?

If you don't want to bother car mechanics, there is always our handy offset calculator. For both performance and safety, it is essential to make sure you get the offset and backspacing right. If you're not careful with your measurements, you might end up spending much more to make things right.

Calculating the offset is uncomplicated and straightforward. All you need to be aware of are a few fundamental measurements, including the wheel width and the distance from where it mounts on its hub to its centerline.

Make sure you always compare the stock offset and backspacing values to the new wheels. If you already have custom wheels installed and enter those numbers instead, it will warp your perspective on what is still safe for your vehicle.

How Much Offset and Backspacing is Okay?

We like uncomplicated things much more than careful and tiresome calculations. And that is why there is a rule of thumb for custom offset that will guarantee your safety on the road. Whenever you choose new wheels, if you stay within the 5 mm range compared to your stock offset, you are safe.

For the aftermarket wheels, backspacing usually ranges from 3.5 inches to 5 inches. Anything more than that requires measurements and careful planning. Too much backspacing can potentially be harmful.