5 Tips To Check Trailer Axle Alignment

Home » 5 Tips To Check Trailer Axle Alignment

In the first place, what exactly is the significance of a Trailer axle? Axles are the main shafts that allow a wheel or gear to rotate. They are made of steel. Trailer axles in poor condition or neglected axles can be extremely dangerous.

trailer axle

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For rotation, the trailer axles are directly connected to the wheels. Furthermore, an axle may be attached to the vehicle, allowing its wheels to rotate around it.

Even in a standard light trailer, the trailer torsion axles must function properly for the vehicle to move.

Unattended, built-up trailer axle kit can cause your trailer’s tires to pop out unexpectedly while driving, which can be dangerous. Consider the scenario in which you are traveling at a high rate of speed on the highway, and your axle fails.

The outcome may be disastrous. Increase the likelihood of something as critical as your axles going unmaintained by ten. Unchecked 3500 ~ 7000 lb axles on your trailer can put you and your passengers in danger.

A thorough examination of the features available for moving 5200 lb trailer axle can yield a long-term solution that will provide greater protection, long service life, and a higher return on capital investment.

Importance Of Checking Trailer Axle Alignment

1.Tips To Align Trailer Axle

2. Alignment Area

3. Inspection

4. Trailer Ride Height

5. Toe Length


1. Tips To Align Trailer Axle

One item that is frequently overlooked – and one that can harm the tracking and cornering, as well as the life of the tires – is the alignment of the axle (s).

 Align Trailer Axle

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It is critical to have accurate wheel alignment or proper suspension geometry in your tow vehicle because it impacts the vehicle’s stability and handling. Especially how long its tires will last.

For the suspension layout to work properly, the castor, camber (whether favorable or unfavorable), and toe-in/tow-out must all be set up as designed for the specific suspension layout. It would help if you considered the roll-axes and instant centers as the wheels/tires move up and down.

Controlling the essential handling qualities of the tow vehicle – oversteer/understeer vs. cornering force – is accomplished by adjusting the front and rear axle weights, spring rates, anti-roll-bar rates, and the bump/rebound settings of the suspension.

When a vehicle’s maximum maneuvering ability is exceeded, the vehicle is inherently designed to ‘plow’ off the road rather than spin off the road.

Changing one of these components, such as stiffening the rear springs, can result in dangerous and unexpected changes in the large tow truck’s handling. It is possible that towing a heavy, high-inertia oscillatory trailer or caravan will exacerbate this situation seriously and unpredictably.

It is also critical for caravans and camper-trailers to be properly aligned, regardless of whether they are equipped with independent suspension or a non-independent (solid-axle) suspension system.

2. Alignment Area

Identify the suitable alignment area from the drop-down menu. This location should be flat, level, and free of any debris. You should check the tires to ensure that each dual wheelset is still within 3/4-inch of one another in circumference size.

Using new tires in conjunction with worn tires will result in unreliable data. The pressure in all of the tires should be the same.

Example: If the trailer does not have sliding doors, alter the trailer’s landing legs to ensure sufficient ground headroom while the trailer is still connected to the tractor.

After that, gently press the trailer service brakes after pulling the trailer forward at least ten feet in either direction. Reduce the height of the trailer landing legs now. Disconnect the trailer from the vehicle. Maintain disengagement of the trailer parking brakes.

It is now necessary to raise the front of the trailer to the height specified by the manufacturer. This intended height should be noted on the trailer’s identification tag.

Measure the distance between the ground and the kingpin mounting plate with a tape measure to determine the height of the kingpin. Adjust the height of the landing legs trailer to the specified kingpin mark.

Confirm the original axle orientation by installing a kingpin extender or adapter and a wheel-end extender, and then check the alignment again. Check that the wheel-end extenders are a perfect pair before using them.

3. Inspection

Following that, take measurements of the wheel-end extension and the length of the axle track. With the help of a tape measure, four separate measurements must be taken.

To properly size the trailer, you must first measure the distance between the kingpin and the end of the wheel extender on the front axle on both flanks of the trailer (A & B).

You’ll also need to measure the distance between the center points of the two external wheels on each side of the trailer to ensure that the trailer is level (C & D).

The front axle target distance (A & B measurement) varies depending on the length of the wheel-end extender and the spacing of the axle track.

The range is +/- 3/16-inch to +/- 7/32-inch depending on the length of the wheel-end extender and the width of the axle track.

This indicates that the trailer axle is within specification and that no adjustment is required.

If there is a difference between the A-B measurements less than or equal to a target value, the axle is out of configuration, and no changes should be made.

The C and D measurements refer to the distance between the axles, measured from the center of one hub to the center of the other hub. To determine these values, a trammel bar should be used.

Assemble the trammel bar by aligning the pointers so that they are in the center of the front and rear axle spindles, respectively. 

These measured values should be accurate to one-sixteenth of an inch. If the distance between them is greater, the rear axle position should be adjusted. 

4. Trailer Ride Height

The ride height is the spacing between the midpoint of the axle and the base of the sub-frame. If it’s a slider crate, the bottom of the crate is the starting point. If it’s a regular trailer flatbed, the bottom frame will be the most vulnerable.

The quickest and most accurate method is to measure from the suspension-mounting surface to the top of the axle. And then, once you’ve determined the diameter of the axle, you can subtract the difference.

Using a tape measure, it is measured from the bottom of the trailer’s subframe up to the top of the axle if it has a five-inch diameter.

Take that measurement and multiply it by 2.5 inches to get the trailer ride height. A description tag is present on all suspensions, and this tag will inform you of the ride height of that particular suspension.

The ride height must be set correctly because you want the suspension to have the max number of jounce, which is up transportation, and rebound, which is down traveling.

What could go wrong if the ride height is not set correctly? We may have air-spring damage. Shock absorbers are susceptible to becoming overextended. The sub-frame of the trailer is the most severely damaged.

5. Toe Length

The final and most important measurement is the axle toe, which has a massive effect on the vehicle’s alignment.

Trace the tire centerline with chalk on both external tires on the front axle using a trammel bar and a chalk pen. Remove the trammel bar and tilt the trailer backward so that the tires rotate one-fifth turn on their own.

Using the same trammel bar as before, but this time starting from the backside of the front axle, scribe a new chalk line in the same manner as before. As soon as the toe reaches zero, the second line marked will be overlaid on the first line marked.

If the two written lines are not superimposed, the spacing between them corresponds to the amount of toe-in or toe-out.

An axle with excessive toe makes it impossible to align the axle to achieve acceptable tire wear.

A bent trailer spindle usually causes an excessive toe due to an impact. The option to adjust the toe on a trailer is to bend the axle, which the manufacturers of trailer axles do not suggest. 


Using a little practice and the right tools, you can quickly determine trailer alignment, allowing you to in maximizing tire wear and fuel economy by ensuring that their trucks are moving down the highway in a straight line. If the trailer axle bend seriously, you’d better replacing the trailer axle.