Wheel offset vs backspacing — difference explained
Differentiate between wheel offset and backspacing for optimal performance.
When choosing a new set of wheels, there are numerous things to consider – wheel diameter, bolt pattern, and the overall size of the wheel. However, two terms keep confusing drivers, and these are offset and backspacing.
These two refer to wheel dimensions in some way, but most drivers don’t know exactly how. They are also interchangeably used terms, while in reality, they represent two completely different measurements. So, our team deals with the matter of wheel offset vs backspacing in this guide to help you get to the bottom of these terms.
Why do wheel offset and backspacing matter?
If you want to get a custom set of wheels for your ride, you have to consider offset and backspacing. Essentially, they both refer to how the wheel fits your vehicle, and they also add up to the style of your wheels.
By properly adjusting the offset and backspacing, you can have custom wheels that stand past the fenders, or get that sporty look of the car. Adjusting the offset and backspacing is quite popular for truck wheels and off-road SUV drivers.
Still, it’s not something just reserved for drivers of big and bulky vehicles, as you can customize the wheels of any car based on these two measurements. Like the diameter of your wheels, offset and backspacing are also measured before you fit them on your vehicle.
We’ll help you get to know the measurement techniques and how to apply them to choose the perfect offset and wheels backspace for your car’s new set of wheels.
About wheel backspacing
Choosing a wheel with specific backspacing and offset is just like deciding between all-terrain vs mud terrain tires, as it adds up to the wheel customization and how they fit on your car. To explain things most understandably, we’ll start with wheel backspacing.
So, backspacing is the measured distance from the center of the wheel hub to the back surface of the wheel. Still, it’s more than just a measurement – wheel backspacing tells you about the space you have for the suspension and braking systems after mounting the wheel.
By choosing a proper backspacing measurement of the wheel, you’ll ensure that there’s no interference between these systems and the wheel. It’s measured in inches, and there’s a unique way of measuring the backspacing yourself.
You should first lay the wheel down with the back side flipped up, and place something straight across the back face. Next, grab a tape measure and precisely measure the distance between the set item and the wheel hub.
When trying to measure the backspace and offset of your wheels, it’s important to start with the backspace for a reason. These two measurements are correlated and you can measure the offset more easily once you know the backspacing.
Knowing the offset and backspacing of the wheels that can fit your car is especially important once you decide to put bigger wheels or custom wheels on your ride. So, now that you have the backspacing already gets you halfway there.
The next thing is to measure the offset – the distance between the mounting surface of the wheel and the dead center of the wheel’s width. However, things get a bit more complicated with the offset when compared to measuring the backspacing of the wheel.
To measure the offset, you’ll first need to find the precise dead center of the wheel’s width. Once you’ve done that, it’s time to measure the distance between the center and the backspace of the wheel. For instance, if you’ve measured your backspacing at 8.5″, and the dead center width of your wheel is at 6″ then the offset will be the difference or 2.5″.
Now, offset is mostly expressed in millimeters instead of inches, so in this case, the wheel offset would be 63.5 millimeters. The offset can drastically affect the wheel interference with other systems near the wheel as well as the looks of your car. There are three common offset types – zero offsets, positive offsets, and negative offsets.
Zero wheel offset
The zero offset means that the center hub of your wheel is aligned with the dead center width of the wheel. Zero offset places the wheel and tire under the fender and it’s a common option for rear-wheel drive cars and off-road vehicles.
This type of offset is perfect for combining everyday driving characteristics with a centered look of the tire. It provides enough space for large ceramic brakes in the back and doesn’t interfere with suspension. Looking at your car’s exterior, the hub assembly will seem a bit deep when compared to the rim.
It’s not as noticeable as with negative offset, but it still looks visually appealing and provides decent backspace for the brakes.
Pros and cons of negative offset
Having negative offset wheels gives you lower backspace when compared to a positive or a zero offset since the mounting surface is closer to the back side of the wheel. It gives you a nice, deep look at the wheels sometimes referred to as “deep dish rims”.
While it certainly looks unique, what are the benefits and downsides of this offset type? Well, a negative offset leaves less backspace, so there’s not as much space for the brakes as with zero offset or positive offset designs.
It pushes your wheel out of the fender line and gives you a nice and deep track. So, a negative offset is perfect for cornering precision, but the steering is a whole other story. Given the tight grip and wide track, you might not get as much feedback with this type of offset. That being said, it’s possible to go through an oversteer if you aren’t used to driving with such specifications.
Pros of negative offset wheels:
- The better grip provided by a wider track
- Firm stance on the road and improved cornering
Cons of negative offset wheels:
- Potential oversteer
- Tires might rub against the fenders
Pros and cons of positive offset
You’ve probably guessed what a positive offset is based on what we discussed so far – it’s when the mounting surface is set inward when compared to the center of the wheel width. This is the most common offset type, and manufacturers include it as a factory wheelset for a good reason.
Naturally, the backspace is wider and you get more space for the brakes. It also helps you put wider tires on your off-road vehicle without the problem of wheel well size. Most performance cars have large ceramic brakes, so a positive offset is needed for the manufacturer to fit in the brakes.
However, you get less clearance for the brakes and suspension as they are much closer to the rim with a positive offset design. So, it all depends on the vehicle type and wheels you are trying to fit.
Pros of positive offset wheels:
- No rubbing against the fenders
- Lets you fit wider tires
- Allows bigger and more powerful brakes
Cons of positive offset wheels:
- Clearance issues as brakes and suspension are closer to the rim
Well, now you know everything that helps make the dilemma on wheel offset vs backspacing a bit easier. It all depends on the type of wheels you are trying to fit in, and the wheel assembly and type of your car as well.
Trucks with smaller brake calipers can fit negative offset wheels easily and get that wider and more aggressive look. On the other hand, performance sedans and coupes with large ceramic brakes need positive offset with more backspace to fit the braking system. If you wish to customize your wheels, make sure to consider both, as they are both equally important and connected.
Do I want more or less backspacing?
It depends on your vehicle’s type since less backspacing means less space for the brakes, and it might not work well on cars that have bigger brakes.
How much backspacing is an offset?
Negative offset wheels have less backspacing, while zero offset and positive offset have more backspacing.
How do I know what backspacing I need?
You can know the backspacing you need by the size of your brakes and the type of suspension. If you need more clearance, to prevent the wheel from interfering with these systems, you’ll need zero offset with more backspace. Positive offset gives you even more backspace, but it offers less clearance, while negative offset results in the smallest backspace and it’s mostly recommended for SUVs and off-road trucks with smaller brakes.