Whether you’re replacing your trailer rims, buying new tyres, or ensuring the safety of your trailer, identifying the correct stud pattern can prevent costly mistakes. In this article, we’ll walk you through how to identify your trailer’s stud pattern, why it’s important, and tips for ensuring accuracy.

What Is a Trailer Stud Pattern?

A trailer stud pattern, often referred to as a bolt pattern, is the arrangement of the lug holes on the trailer’s hub. These patterns determine which wheels can be mounted on the trailer. They are expressed as a combination of two numbers: the number of lug holes and the diameter of the circle that passes through the centre of those holes. For example, a common stud pattern is 5×114.3, where 5 refers to the number of lugs and 114.3mm is the diameter of the circle.

Why Is Identifying the Right Stud Pattern Important?

Ensuring that your wheels are compatible with your trailer’s hub is critical for both safety and performance. Using a mismatched wheel can lead to uneven wear, unsafe driving conditions, or even a complete failure of the wheel assembly. Knowing the exact stud pattern can help avoid these issues and ensure your trailer runs smoothly.

How to Identify Your Trailer’s Stud Pattern

Count the Lug Holes

The first step is to determine how many lug holes are present on your trailer’s hub. This number will generally be between 4 and 8, depending on the size and weight of your trailer. For example, smaller trailers may have 4 or 5 lugs, while heavier trailers might require 6 or more.

• 4-lug: Common in light trailers.
• 5-lug: One of the most common patterns for medium-weight trailers.
• 6-lug or more: Typically found in larger, heavy-duty trailers.

Measure the Bolt Circle Diameter (BCD)

Once you’ve counted the lug holes, the next step is to measure the diameter of the circle that the lug holes create. Here’s how:

• For even numbers of lug holes (4, 6, etc.): Measure from the centre of one lug hole directly across to the centre of the opposite lug hole.
• For odd numbers of lug holes (5, 7, etc.): Measure from the centre of one lug hole to the outer edge of the hole furthest from it.

Make sure to measure in millimetres, as bolt patterns are usually expressed in metric units. For example, a 5-lug trailer may have a bolt circle diameter of 114.3mm, expressed as 5×114.3.

Check the Stud Size

Stud size refers to the diameter of the lug bolts that secure the wheel to the hub. Measure the stud diameter using a caliper for the most accurate result. This is particularly important if you’re replacing or upgrading your wheels.

Confirm with Manufacturer Specifications

Once you’ve measured your trailer’s stud pattern, it’s always a good idea to confirm with the manufacturer’s specifications. Many manufacturers provide stud pattern details in the trailer’s manual or on their websites. This ensures that your measurements are accurate and prevents issues when ordering new parts.

Stud Pattern Table

IMPORTANT: The lines highlighted in yellow are the products we supply.

Common Trailer Stud Patterns

Here are some of the most common stud patterns you might encounter on trailers in Australia:

• 4×100: Found on lighter trailers.
• 5×114.3: One of the most popular patterns for medium trailers.
• 6×139.7: Often used in heavy-duty trailers.

Troubleshooting Common Issues

Even when following the correct process, it’s easy to encounter a few hiccups when identifying a stud pattern. Here are some tips to overcome common challenges:

• Difficulty in Measuring: If you’re struggling to get an accurate measurement, it’s best to use a digital caliper or consult a professional.
• Worn Studs or Bolt Holes: In older trailers, the lug holes may be worn, making measurements more difficult. When in doubt, compare with a new or less worn part.
• Mismatched Wheels: If you’re unsure whether the wheel matches your stud pattern, seek professional advice before installation. Mismatched wheels can be dangerous.

Make sure to consult your trailer’s manual for specific details, and when in doubt, don’t hesitate to contact us. Keeping your trailer in top condition starts with the basics, and knowing your stud pattern is one of the most important fundamentals.