How to correctly measure and choose appropriate PCD in the wheel?

When we buy wheels for our cars, many people will face a problem: They don’t know what PCD is and how to measure PCD. This article will introduce how to measure and choose appropriate PCD for your wheels in detail.

INTRODUCTION:

Bolt Pattern

Bolt pattern or bolt circle means the diameter of an imaginary circle formed by the centers of the wheel lugs, which can be 4-, 5-, 6-, or 8-lug holes, while less common have 3, 7, or 10 lug bolt patterns.

A bolt circle of 4×100 would indicate a 4-lug pattern on a circle with a diameter of 100mm.

Dual Drill Bolt Patterns

Dual bolt patterns are wheels that have two different bolt patterns on the same wheel. This allows you to mount them on multiple vehicles. These wheels offer greater versatility and can be used on a broader range of cars.

Lug Bolts

Lug bolts have a shank that gets threaded into the wheel hub. They also have a shoulder near the end that sits against the wheel, helping keep it in place.
Lug bolt length is another factor to keep in mind. The wheel won’t fit flat against the hub if the lug bolts are too long. Alternatively, a shorter lug bolt won’t be able to grab the threads to provide a secure fit.

Lug Nuts

Lug nuts secure a wheel to a vehicle’s hub.
As opposed to lug bolts, lug nuts have internal threads allowing them to screw onto the wheel studs. The thread pitch and length must be compatible with your specific vehicle to avoid complications down the road.

How to correctly measure PCD?

The detailed way to measure and choose appropriate PCD  is as follows:
1.Identify the size of the rim or tyre size. (This helps to narrow down the likely PCD sizes)
2. Measure the distance ‘S’ between two adjacent studs from the centre of each hole. (see diagrams below)
3. Using the relevant diagram depending on the number of studs you have you should be able to identify the correct PCD.

Note about how to measure appropriate PCD:

1. When measuring a 5-lug wheel, you cannot measure in the same way as with a 4-bolt hole rim, because the holes aren’t directly opposite to each other, so the measurement is only an estimate unless accurately measured using a bolt pattern gauge, which is a specialty tool and not widely available.

2.Imperial sizes are commonly used on UK trailers whereas European trailers use metric.

Finally it is very important to check the the wheel’s offset and center bore to match the vehicle’s specifications to ensure proper fitment and avoid potential issues.