If you are shopping for aftermarket wheels, you have probably seen specifications such as +35, +20, 0 or -12 offset. But what does wheel offset mean?
Wheel offset is the distance, measured in millimetres, between the wheel’s centreline and the surface where the wheel mounts to the vehicle hub. It determines how far inward or outward the wheel sits. The correct offset helps provide proper clearance around the suspension, brakes and fenders.
Understanding offset is especially important when changing wheel width, lowering a car, lifting a truck or moving from factory wheels to aftermarket wheels.
What Does Offset Mean on Wheels?
Think of a wheel from the side.
There is an imaginary line running directly through the middle of the wheel. That is the wheel centreline.
There is also a flat surface on the back of the wheel that contacts the vehicle hub. That is the hub mounting surface.
The distance between those two points is the wheel offset.
Offset is normally expressed in millimetres and may appear on a wheel as an ET number, such as:
- ET45
- ET35
- ET20
- ET0
- ET-12
The offset tells you where the wheel will sit relative to the suspension and fender.
In simple terms:
Higher positive offset = wheel sits farther inward.
Lower or negative offset = wheel sits farther outward.
That is why two wheels with the same diameter can sit very differently on the same vehicle.
Positive vs Zero vs Negative Wheel Offset
There are three basic types of wheel offset.
Positive Offset
A wheel has positive offset when the mounting surface is positioned toward the outside face of the wheel.
Examples include:
- +20 mm
- +35 mm
- +45 mm
Positive offset generally moves more of the wheel inward toward the suspension.
Many modern passenger cars and factory wheel setups use positive offset.
For example, if your factory wheel has a +45 mm offset and you replace it with a similar-width wheel with +30 mm offset, the new wheel will sit farther outward.
The difference in offset is 15 mm.
That does not automatically mean the new wheel will fit, however, because wheel width, tire size and suspension clearance also need to be considered.
Zero Offset
A zero-offset wheel has its mounting surface directly on the wheel centreline.
This is normally listed as:
0 mm or ET0
The wheel is positioned evenly around the mounting surface.
Zero-offset wheels are less common on many modern passenger cars but may appear in certain truck, off-road or custom applications.
Negative Offset
A wheel has negative offset when the mounting surface is positioned toward the inside of the wheel.
Examples include:
- -6 mm
- -12 mm
- -24 mm
Negative offset pushes the wheel farther outward from the vehicle.
This can create a wider, more aggressive stance, but too much negative offset may also cause the tire to extend past the fender or change how the vehicle steers and handles.
Negative-offset wheels are commonly associated with some truck and off-road builds, although the appropriate offset depends entirely on the vehicle and setup.
What Does +35 Offset Mean?
A +35 wheel offset means the wheel’s mounting surface is located 35 mm toward the outside face of the wheel from its centreline.
Because the mounting surface moves outward, the wheel itself is positioned farther inward toward the vehicle.
For example, Too Fast Auto Parts carries aftermarket wheels with specifications such as 18x8.5 +35, where:
- 18 = wheel diameter in inches
- 8.5 = wheel width in inches
- +35 = wheel offset in millimetres
Offset should never be evaluated by itself.
An 18x8.5 +35 wheel and an 18x10.5 +35 wheel have the same offset number but occupy very different amounts of space inside the wheel well.
Does a Lower Offset Make the Wheel Stick Out More?
Generally, yes.
When comparing wheels of the same width, reducing the offset moves the wheel farther outward.
For example:
+45 → +35 → +20 → 0 → -12
The wheel progressively moves outward as the offset decreases.
This is why drivers looking for a more flush or aggressive stance often consider a lower offset.
But going lower is not automatically better.
Moving the wheel too far outward can create problems with:
- Fender clearance
- Tire rubbing
- Steering geometry
- Suspension loading
- Wheel bearing loading
- Local tire and fender coverage requirements
Fitment should always come before appearance.
How Wheel Width Changes Offset Fitment
One of the most common mistakes when choosing aftermarket wheels is comparing offset numbers without comparing wheel width.
Consider these two wheels:
18x8 +35
and
18x10 +35
Both have +35 offset, but the 10-inch-wide wheel extends farther both inward and outward because it is two inches wider.
This means that simply finding another wheel with the same offset as your factory wheel does not guarantee identical fitment.
When changing wheels, evaluate at least:
- Diameter
- Width
- Offset
- Bolt pattern
- Centre bore
- Tire size
- Brake clearance
If the vehicle is modified, suspension height and alignment should also be considered.
Wheel Offset vs Backspacing
Wheel offset and backspacing are related, but they are not the same measurement.
Wheel offset measures the position of the mounting surface relative to the wheel centreline and is usually expressed in millimetres.
Backspacing measures the distance between the wheel’s inner edge and the hub mounting surface.
Both measurements help determine how much space a wheel occupies inside the wheel well.
If you already have a wheel and need to determine its offset manually, see our complete guide:
How to Measure Wheel Offset Before You Buy
That guide explains how to measure backspacing, wheel width and calculate the offset before ordering another wheel.
What Happens If Wheel Offset Is Wrong?
Incorrect offset can create several fitment problems.
Tire or Fender Rubbing
If the wheel sits too far outward, the tire may contact the fender or fender liner when turning or when the suspension compresses.
This is especially important on lowered vehicles or when using wider tires.
Suspension Clearance Problems
If the wheel sits too far inward, the wheel or tire may contact components such as the:
- Strut
- Coilover
- Upper control arm
- Tie rod
- Sway bar
- Frame
A wheel may appear to fit while the car is parked but rub once the steering is turned or the suspension moves.
Brake Clearance Problems
Offset contributes to wheel position, but brake clearance also depends on the wheel’s spoke and barrel design.
Two wheels with the same width and offset may not provide identical brake caliper clearance.
Changes in Steering Feel
Moving the wheel significantly inward or outward changes its position relative to the vehicle’s original steering geometry.
Large changes from the factory setup can affect steering feel and vehicle behaviour.
Additional Load on Wheel Bearings and Suspension Components
Aggressive fitment that moves the wheel substantially outward can increase leverage on wheel bearings and suspension components.
That does not mean every aftermarket offset causes problems. It means substantial fitment changes should be planned as part of the complete wheel, tire and suspension setup.
How Do You Choose the Right Wheel Offset?
There is no universal “best wheel offset.”
The right offset depends on your specific vehicle and the rest of the wheel setup.
Before ordering aftermarket wheels, start with your vehicle information:
- Year
- Make
- Model
- Trim
- Factory wheel size
- Current tire size
Then determine whether the vehicle has modifications such as:
- Lowering springs
- Coilovers
- Lift kit
- Leveling kit
- Larger brakes
- Wheel spacers
- Wider tires
- Fender modifications
Once you know the original specifications, compare the new wheel’s width and offset together.
Do not choose an offset simply because another vehicle online appears to use the same number.
Different trims, brakes, suspensions and tire combinations can produce very different results.
Should You Use the Factory Wheel Offset?
The factory offset is a useful starting point, especially when the vehicle remains mostly stock.
However, aftermarket wheels are frequently wider than factory wheels. That means the ideal aftermarket offset may not be identical to the original number.
For example, moving from an 8-inch-wide factory wheel to a 9.5-inch aftermarket wheel changes both inner and outer clearance before offset is even considered.
The goal is not necessarily to duplicate the factory offset number.
The goal is to choose a wheel width and offset combination that provides appropriate clearance and the desired wheel position.
Do Wheel Spacers Change Offset?
Yes.
A wheel spacer pushes the wheel outward, effectively reducing its positive offset.
For example:
A +35 mm wheel with a 10 mm spacer will sit approximately like a +25 mm wheel from a positioning standpoint.
However, wheel spacers introduce additional fitment and hardware considerations.
Rather than automatically adding spacers after purchasing the wrong wheel specification, it is better to determine the appropriate wheel dimensions before ordering whenever possible.
Choosing Aftermarket Wheels in Canada
When shopping for aftermarket wheels in Canada, offset should be considered alongside every other major fitment specification.
Too Fast Auto Parts offers aftermarket wheels for cars, trucks and SUVs in multiple diameters, widths, bolt patterns, offsets and finishes.
Drivers looking for performance-oriented wheel designs can also explore our Aodhan Wheels collection.
Already have aftermarket wheels and need replacement caps? Browse our Aftermarket Wheel Center Caps.
Always confirm the exact specifications shown on the individual product page before ordering.
Need Help Choosing the Right Wheel Offset?
Wheel fitment is about more than finding a wheel that looks good.
Before ordering, have the following information ready:
- Vehicle year, make and model
- Trim
- Current wheel size
- Current tire size
- Preferred new wheel size
- Suspension modifications
- Brake modifications
- Desired stance or fitment
The Too Fast Auto Parts team can help you narrow down suitable aftermarket wheel options based on your vehicle and setup.
Shop Wheels or contact Too Fast Auto Parts with your vehicle information before purchasing if you are unsure about fitment.
Frequently Asked Questions About Wheel Offset
What does wheel offset mean in simple terms?
Wheel offset tells you how far inward or outward a wheel sits on the vehicle. It measures the distance in millimetres between the wheel’s centreline and the hub mounting surface.
What does +35 offset mean?
A +35 offset means the wheel mounting surface is positioned 35 mm toward the outside face of the wheel from its centreline. Positive offset generally positions the wheel farther inward.
Does a lower offset stick out more?
When comparing wheels of the same width, yes. A lower offset moves the wheel farther outward. For example, a +20 wheel will sit farther outward than a +40 wheel of the same width.
Is positive or negative wheel offset better?
Neither is automatically better. The correct offset depends on the vehicle, wheel width, tire size, suspension, brakes and desired fitment.
Can the wrong offset cause tire rubbing?
Yes. A wheel that sits too far outward may rub the fender, while a wheel that sits too far inward may contact suspension components.
Can I use a different offset from the factory wheels?
Often, yes, particularly when changing wheel width. However, the complete fitment needs to be checked rather than comparing only the offset number.
Does wheel width affect offset?
Yes. Wheel width and offset must be evaluated together. Two wheels with identical offsets but different widths will not occupy the same position inside the wheel well.
Where can I find the offset on a wheel?
Many wheels have the specification stamped or cast into the back of the wheel. It may appear as an ET number, such as ET35 or ET20. The product specifications should also list the offset when buying new aftermarket wheels.