Determining Weight and In What Position to Install Axles on a Trailer Build

Question:

How do I determine the weight of an axle without having to buy one and put it on a scale? Is there a chart of standard or approximate weights for axles, springs, brakes, wheels, and tires according to their weight ratings? Part of the weight an axle needs to support is its own weight and that of the springs, brakes, wheels, and tires. But in a tandem or triple axle arrangement one axle set does not need to bear the weight of the others. Together they share the weight of the trailer plus its cargo. But vendors dont list the weight of their axles or axles packages. I am trying to design a trailer which has significantly more weight forward of the axles than usual and need to compute where to place the axles so that they bear the appropriate percentage of the load 85 to 88 vs. 12 to 15 for the tongue. Each axle will bear 100 of its own weight. I need that weight to position them according to the rest of the anticipated load. The standard 60/40 location will put too much weight on the tongue.

asked by: Randall S

Expert Reply:

On our site, we list the shipping weight of our products, including axles. The shipping weight of our axles will be listed on that axles product page. For example, the Trailer Axle 5 on 4-1/2 Bolt Pattern - 3,500 lbs # e43SR will list the length of the axle, in this parts case 89 inches, the weight rating, 3,500 lbs, and the shipping weight of the axle which for this part is 101 lbs. This physical weight will be pretty exact in that the shipping material for this product adds very minimal weight when shipping. This weight will include the brake and drum assemblies. Other than this information, there is no chart from any of the axle manufacturers that lists the physical weight of the axles and axle components.

Axle weights can vary from axle to axle within the same weight capacity due to the varying lengths of axles. For example, an axle with a 2,000 lbs rating will vary in weight between the 60 and 72 inch lengths.

I have attached a photo that will show you how you can determine where to place your axles based on what your estimated tongue weight will be on your trailer. The formula in the picture will help you determine the placement of your axles by determining if your tongue weight will be more or less than 10 percent of the total carrying weight of your trailer.

The width of the axle and width of the trailer need to be inline with each other. You do not want to have an axle that is too long or too short for your application. You will need to measure the width of the under frame where you will be mounting the spring seats for the axle. From these points, you can get the distance you will need from the spring seat to the hub face of the axle.This measurement will allow you to figure out where you want your trailer wheels will ride on the trailer.

If you can tell me what the axle weight capacity and length of axle you are looking for, I can send a list of parts and their approximate weight per axle. It is important to know what the length of axle you will need on your trailer.

expert reply by: Jared P