Understanding wheel stud patterns and bolt pattern measurements is essential for selecting the right wheels for your vehicle. This guide will cover the fundamentals, including definitions, types, measurement methods, and display formats, and provide a conversion chart for reference.
What Is A Stud Pattern?
The short answer is: A stud pattern refers to the arrangement of bolt holes on a wheel, dictating how the wheel attaches to the vehicle’s hub. It is typically denoted by two numbers: the number of bolt holes and the diameter of the circle they form (e.g., 5×114.3). This pattern ensures that the wheel aligns correctly with the hub for safe and secure installation.
Types Of Stud Patterns
Bolt patterns vary based on the number of bolt holes and their arrangement. Common types include:
4 Lug: Features four bolt holes arranged in a square or “+” pattern.
5 Lug: Consists of five bolt holes in a pentagonal layout.
6 Lug: Comprises six bolt holes forming a hexagon.
8 Lug: Includes eight bolt holes arranged in an octagonal pattern.
Dual Drill: Contains multiple sets of bolt holes to accommodate different vehicles.
The number of lugs often correlates with the vehicle’s weight and intended use, with more lugs providing greater strength for heavier applications.
How To Measure Wheel Stud Pattern?
Accurately measuring wheel stud pattern is crucial for ensuring compatibility with new wheels. Here’s how to do it:
Measuring 4-Lug, 6-Lug, and 8-Lug Patterns
For even-numbered lug patterns, measuring is straightforward. The bolt holes are evenly spaced, so you can measure from the centre of one stud to the centre of the one directly across from it.
Steps:
- Select two opposite studs (they should form a straight line).
- Measure from the centre of one stud to the centre of the stud directly across from it.
- The measurement is your bolt circle diameter (BCD).
Example Measurements:
- 4-lug example: A 4-lug pattern with a 100mm measurement is written as 4×100.
- 6-lug example: A 6-lug pattern with a 139.7mm measurement is written as 6×139.7.
- 8-lug example: An 8-lug pattern with a 165.1mm measurement is written as 8×165.1.
Measuring 5-Lug Patterns
Measuring a 5-lug pattern is slightly trickier because there is no directly opposite lug. Instead, you measure from the centre of one stud to the outside edge of the farthest stud (not centre to centre).
Steps:
- Pick one stud and find the stud directly across from it (not the adjacent ones).
- Measure from the centre of the starting stud to the outer edge of the opposite stud.
- This gives you the bolt circle diameter (BCD).
Example Measurements:
- 5×114.3 means it has 5 lugs with a 114.3mm bolt pattern.
- 5×120 means it has 5 lugs with a 120mm bolt pattern.
What Is Pitch Circle Diameter (PCD)?
The Pitch Circle Diameter (PCD), also known as the Bolt Circle Diameter (BCD), is the measurement of the imaginary circle that passes through the centre of all the bolt holes on a wheel or hub. This diameter is a crucial factor in determining wheel fitment, as it dictates whether a wheel will align correctly with the vehicle’s hub. The measurement is typically expressed in millimetres (mm) or inches and is included in the bolt pattern notation (e.g., 5×114.3 means five bolt holes arranged in a 114.3mm diameter circle).
How Bolt Pattern Measurements Are Displayed?
Bolt pattern measurements are typically presented in a two-number format:
Number of Bolt Holes X Pitch Circle Diameter
For example, a “5×114.3” pattern indicates five bolt holes arranged in a circle with a 114.3 mm diameter. This standardized notation helps identify and match compatible wheels and hubs.
Bolt Pattern Conversion Chart
Converting bolt pattern measurements between inches and millimetres is helpful when selecting wheels, especially for vehicles with different measurement standards. Understanding these conversions ensures you can accurately match aftermarket wheels to your vehicle’s hub. Below is a quick reference chart to help with common bolt pattern conversions.
| BOLT PATTERN | MILLIMETERS | INCHES |
| 4 LUG | 4×98 | 4×3.86 |
| 4 LUG | 4×100 | 4×3.94 |
| 4 LUG | 4×108 | 4×4.25 |
| 4 LUG | 4×110 | 4×4.33 |
| 4 LUG | 4×114.3 | 4×4.5 |
| 5 LUG | 5×98 | 5×3.86 |
| 5 LUG | 5×100 | 5×3.94 |
| 5 LUG | 5×105 | 5×4.13 |
| 5 LUG | 5×108 | 5×4.25 |
| 5 LUG | 5×110 | 5×4.33 |
| 5 LUG | 5×112 | 5×4.41 |
| 5 LUG | 5×114.3 | 5×4.5 |
| 5 LUG | 5×115 | 5×4.52 |
| 5 LUG | 5×118 | 5×4.65 |
| 5 LUG | 5×120 | 5×4.72 |
| 5 LUG | 5×127 | 5×5 |
| 5 LUG | 5×130 | 5×5.12 |
| 5 LUG | 5×135 | 5×5.3 |
| 5 LUG | 5×139.7 | 5×5.5 |
| 5 LUG | 5×150 | 5×5.91 |
| 6 LUG | 6×114.3 | 6X4.5 |
| 6 LUG | 6X120 | 6X4.72 |
| 6 LUG | 6X130 | 6X5.12 |
| 6 LUG | 6X135 | 6X5.3 |
| 6 LUG | 6X139.7 | 6X5.5 |
| 8 LUG | 8×165.1 | 8X6.5 |
| 8 LUG | 8×170 | 8X6.69 |
| 8 LUG | 8×180 | 8X7.09 |
In this blog post, you’ll gain a clear understanding of stud patterns and how to measure them, allowing you to confidently choose wheels that fit your vehicle while ensuring safety and optimal performance.
