Measuring the Wheel Hub

The wheel hub is the central rotating part that holds the wheel in place. It contains bearings and connections for ABS and tracking sensors. To measure the wheel hub, you first need to remove the wheel.

You can do this with a wrench, once you have lifted the vehicle using a jack or hydraulic lift.

Next, to access the wheel hub, you’ll need to remove the brake drum. Loosen it to remove it from the wheel.

You’ll then see the exposed wheel hub, ready for measurement. Measure across the middle of the wheel hub to get the diameter.

How to Measure Wheel Hub Bolt Pattern

The wheel hub bolt pattern is the number of bolts lugs on the hub and the diameter of the circle in which they are arranged.

The pitch circle diameter (PCD) is the number of wheel bolts and the diameter of an imaginary circle if you drew it through the middle of each of the bolts in the pattern.

If you are swapping wheels, your new wheel will need an identical PCD to the one you’re replacing.

To get the PCD you must measure the wheel bolt pattern:

• In five-bolt patterns, start from the middle of one lug and measure to the outside of the next but one lug
• In four or six-bolt patterns, measure from the middle of one lug to the outside of the opposite lug in the pattern.

How to Measure Wheel Hub Bore Size

The wheel hub size needs to match the centre bore of the wheel perfectly. The centre bore is the hole in the middle of the back of the wheel.

Wheels do come in different hub and centre bore sizes.

Generally, callipers won’t fit inside a wheel, so you will need a ruler or tape measure for this.

Normally the centre bore is covered by a cap, but you can easily pop this off to see the hole underneath.

How to Get the Right Fit

You have three measurements for fitting a new wheel hub:

• Wheel hub
• Bolt pattern
• Bore size.

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