Wheel/Rim Size Guide for Beginners

Understanding Wheel Sizes – Find the Right Fit for Your Vehicle

Not all wheels fit every car! Choosing the right alloy wheels requires understanding wheel diameter, width, offset, bolt pattern (PCD), and centre bore. Use this guide to help you find wheels that match your vehicle for optimal safety, performance, and style.

What Is Wheel Diameter?

Wheel diameter is the size of the wheel measured in inches, excluding the tyre. It plays a crucial role in vehicle handling, comfort, and aesthetics.

Example:

6.5×15 → 15 inches is the wheel diameter, 6.5 inches is the wheel width.

  • Standard passenger cars typically use 14” to 19” wheels.
  • Luxury, performance, SUV, and 4×4 vehicles tend to have larger diameter wheels for enhanced road presence and grip.

What Is Wheel Width?

Wheel width determines the range of tyre sizes that can fit on the wheel.

Example:

6.5×15 → 6.5 inches is the wheel width, 15 inches is the diameter.

Tyre Fitment Guide for 6.5-inch Width Wheels:

  • Minimum Tyre Width: 185mm
  • Ideal Tyre Width: 195mm – 205mm
  • Maximum Tyre Width: 215mm

Wider wheels improve road grip, handling, and braking performance. However, ensure your chosen width aligns with your vehicle’s suspension and body clearance.

What Is Wheel Offset?

Wheel offset is measured in millimetres (mm) and determines how far the wheel sits inwards or outwards relative to the vehicle’s body.

Offset Types:

  • Zero Offset (ET0): The mounting face is exactly in the centre of the wheel.
  • Positive Offset (ET38, for example): The mounting face is positioned closer to the outer edge of the wheel. Common for front-wheel-drive and newer vehicles.
  • Negative Offset (-12, for example): The mounting face is further inside the wheel. Common for off-road and performance vehicles.

Choosing the correct offset is crucial! Incorrect offset can cause wheels to rub against fenders, brake calipers, or suspension components, leading to safety hazards.

What Is PCD (Pitch Circle Diameter)?

PCD is the diameter of an imaginary circle passing through the centre of all the wheel bolts/lug nuts.

  • PCD is measured in millimetres (mm).
  • Different vehicles have different bolt patterns:
  • Most cars have 4, 5, 6, or 8 lug holes, depending on the make and model.

Always check your vehicle’s PCD before purchasing new wheels.

What Is Centre Bore?

The centre bore is the hole in the middle of the wheel that fits onto the hub of your vehicle.

  • Measured in millimetres (mm).
  • If the centre bore is too small, the wheel will not fit.
  • If the centre bore is too large, spigot rings must be used to ensure the wheel sits securely on the hub.

A proper centre bore fitment ensures wheel stability and eliminates vibrations while driving.

 

Get Expert Assistance at Tiger Wheel & Tyre Botswana

Not sure which wheels fit your car? Our specialists can help you:

  • Choose the correct wheel size, offset, and PCD for your vehicle.
  • Ensure proper wheel balancing and alignment for a smoother ride.
  • Get professional fitment for enhanced safety and performance.

Visit Your Nearest Tiger Wheel & Tyre Botswana Store today!