Bolt Pattern & Trailer Towing Capacity

Aug 12, 2023 | Trailer Axles

This article answers the popular question, Does my trailer’s bolt pattern reveal my trailer’s towing capacity?

What is a bolt pattern?

First, let’s understand what a bolt pattern is. A bolt pattern, also known as a lug pattern, is determined by the number of bolt holes on your wheel, and the diameter of the circle that they form. 

How do you measure your trailer’s bolt pattern? 

The process is simple. First count, then measure. This helpful article from BlueSwift Axles will walk you through the process of accurately measuring your bolt pattern. There is a different process for measuring the bolt pattern with an odd or even number of bolts.

Does your bolt pattern determine your trailer’s towing capacity?

Your trailer’s wheel bolt pattern is not the most accurate way to reveal your trailer’s actual weight capacity. But, it can help you narrow it down and get a close idea of your trailer’s max towing capacity.

For example, If you’ve also got 6 bolts, you know it’s probably not a 7,000-lb axle, since most axles of that capacity have 8 lugs. So you’re likely looking at either a 2,500-lb axle or a 5,200-lb axle.

The general rule of thumb for bolt pattern & towing capacity

Please note: These are just towing capacity estimates, and you should always refer to your trailer’s axle rating for the most accurate towing capacity on the trailer. 

  • 4 Bolt = 2K
  • 5 Bolt = 2K or 3.5K
  • 6 Bolt = 2.5K or 5.2K
  • 8 Bolt = 6K, 7K, 8K

What makes up the axle rating?

The axle rating limit includes the weight of the trailer and all of the trailer’s cargo. Oftentimes, people forget to factor in the total weight of the trailer when empty before loading it with cargo. For example, a trailer that has two 3,500 lb axles has an axle rating of 7,000 pounds. The trailer may weigh 2,500 pounds, leaving the remaining towing capacity for cargo at 4,500 lb.

Read this article to learn more about why knowing your axle’s rating is important.