Bolt Pattern 101 - How to measure a lug pattern in a wheel or car.
We’ll start off by answering the question, what’s a bolt pattern? A bolt pattern, also known as the lug pattern or PCD (pitch center diameter), is the measurement of an imaginary circle formed by the lug holes at the center of your wheel.
The first number indicates how many bolt holes or wheel studs the wheel or vehicle has. The second number is the diameter of the imaginary circle around the holes. For example, a wheel with a 5x100 has 5 lug holes equally spaced around a circle with a 100mm diameter, the same goes for the wheel studs on the vehicle.
Now that’s pretty easy, right?
Typically, larger vehicles have more lugs, while smaller vehicles have fewer. Found on passenger cars, SUVs and small pickups, wheels/cars with a five lug pattern are the most common. Four, six and eight are also used.
And why does your wheel lug pattern matter to you? That’s a good question!
Knowing your bolt pattern is critical because it’s how your wheels are secured to your vehicle using lug nuts or lug bolts. Having the right bolt pattern ensures a proper fit, and nothing is more important than safety. It’s usually not necessary to measure the bolt pattern on the vehicle because extensive data is kept on that aspect. More common use is on wheels, new wheels will be ordered to match the car but in the case of a used set of wheels the pattern is usually not marked so measuring is required.
Never try to install wheels on your vehicle that don’t match your OE bolt pattern, no matter how close in size they might seem to be. The wrong bolt pattern can prevent the wheel from mounting safely.
4-bolt patterns are measured in a straight line from center to center of two bolt holes sitting directly across from each other.
5-bolt patterns can be more difficult to measure since the bolt holes are not directly across from each other. This one is the most common to be measured incorrectly, unlike 4, 6 or 8 lug it's not center to center. You can estimate the measurement by using a straight line from the outside edge of one hole to the center of the third bolt hole. The accurate measurement is depicted here and can only be measured with a special tool called a bolt pattern gauge or by using a complex geometric equation.
6-bolt patterns are measured in a straight line from center to center of two bolt holes sitting directly across from each other.
8-bolt patterns are measured in a straight line from center to center of two bolt holes sitting directly across from each other.
Available for purchase is a sliding bolt pattern gauge, it's inexpensive and a great option to keep in your tool box.
Please ask if you have any questions, we're here to help!