How to Find the Correct Alloy Wheel Size for Your Car
Choosing the correct alloy wheel size is essential if you want your wheels to fit safely and perform properly. Alloy wheels are not universal, and even cars from the same manufacturer can use different wheel sizes depending on the model, year, trim level and engine type.
Whether you are replacing a damaged alloy wheel, upgrading your car’s appearance, or buying a used set of alloys, it is important to check the correct wheel specifications before you buy.
Why Alloy Wheel Size Matters
The right alloy wheel size affects more than just how your car looks. Incorrectly sized wheels can cause problems with steering, handling, tyre wear, braking and suspension clearance.
If the wheels are too large, too wide, or have the wrong offset, they may rub against the wheel arches or suspension components. If the bolt pattern or centre bore is wrong, the wheels may not fit the car at all.
Where to Find Your Current Wheel Size
One of the easiest ways to find your alloy wheel size is to check the wheels already fitted to your car. The wheel size is often stamped or cast into the back of the alloy wheel.
You may see a marking such as 17x7.5J ET45. This means the wheel is 17 inches in diameter, 7.5 inches wide, and has an ET45 offset.
Check Your Tyre Size
Your tyre size is printed on the sidewall of the tyre and may look like 225/45 R17. In this example, 225 is the tyre width in millimetres, 45 is the tyre profile, and R17 means the tyre fits a 17-inch wheel.
The final number tells you the wheel diameter. However, tyre size alone does not tell you everything. You still need to check wheel width, PCD, offset and centre bore.
Check Your Vehicle Handbook
Your vehicle handbook may list the recommended wheel and tyre sizes for your car. The handbook may show more than one approved size, depending on your vehicle specification.
What Is PCD?
PCD stands for Pitch Circle Diameter. It refers to the number of bolt holes on the wheel and the diameter of the circle they form. A PCD of 5x112 means the wheel has five bolt holes and a 112 mm pitch circle diameter.
What Is Offset?
Offset is the position of the wheel’s mounting face in relation to the centre line of the wheel. It is usually shown as an ET number, such as ET35, ET40 or ET45.
What Is Centre Bore?
The centre bore is the hole in the middle of the alloy wheel that fits over the hub of the car. If the centre bore is too small, the wheel will not fit. If it is too large, spigot rings may be needed.
Can You Fit Bigger Alloy Wheels?
In many cases, it is possible to fit larger alloy wheels, but you need to be careful. Bigger wheels often need lower-profile tyres to keep the overall rolling diameter close to the original size.
Changing wheel size can affect ride comfort, handling, tyre cost, fuel economy, speedometer accuracy, brake clearance and suspension clearance.
Checklist Before Buying Alloy Wheels
Before buying replacement alloy wheels, check:
- Wheel diameter
- Wheel width
- PCD
- Offset
- Centre bore
- Tyre size
- Load rating
- Brake clearance
- Vehicle make, model and year
- Whether the wheel is OEM or aftermarket
Frequently Asked Questions
Check the wheel diameter, width, PCD, offset, centre bore, load rating and tyre compatibility. Do not rely on appearance alone.
Need Help Finding the Right Size?
Finding the correct alloy wheel size can feel confusing, but checking the right details before you buy can save time and money. Search by wheel size, manufacturer or vehicle model to find compatible options for your car.