Uneven tire wear on trailers is a frustrating but remarkable common occurrence. Many trailer owners find themselves asking this question quite frequently when examining or replacing trailer tires.
The primary causes for trailer tires’ uneven wearing are bent axles, riding on incorrect tire pressure, overloaded or underloaded trailers. In addition, too much load for the tires to handle, wheel misalignment, bent struts, bent wheels from potholes, or similar road hazards are among other reasons.
With various reasons why your trailer tires are wearing unevenly, let’s look at these in more detail and how you can prevent or at least reduce your trailer tire wear.
What Is The Camber Effect
In general, trailer tires don’t wear evenly due to the physics of the tires being under load. The Camber effect measures how straight-up-and-down the tires are under load, and you will find then when the inside of the tires wear out faster than the outside.
Unloaded trailer tires are duck-footed if they point outwards as the trailer axle is built with a slight upward bend; when loaded, the axle flattens out and brings the tires into more significant contact with the road across the tire surface.
Properly aligning the trailer wheels can rectify The negative camber effect. Ensuring proper alignment means that the wheels and tires will come down straight and prevent uneven wear when the trailer is loaded.
Uneven Tire Wear Could Be Due To A Bent Axle
The trailer axle bends slightly upward by default, but when it has been overloaded too many times and incurs damage, the axle remains in the ‘bent down’ position as if it was under load.
When the axle is bent, it will cause the tires to wear unevenly on the inside as it keeps them pointing inwards, even if the trailer itself has little or no load.
How Do Trailer Tires Wear When Under- And Overloaded
The wear on trailer tires is different when underloaded vs. overloaded.
When the weight on the trailer is too light, the tire wear will be focused on the outside of the tire as there isn’t enough weight on the axle to bring the tire to a straight up and down position, so it remains ‘pigeon-toed’ while driving.
When overloaded, the axle bends too profoundly, and this causes the tires to wear on the inside as they now point in the opposite direction to being underloaded. If you see all four tires wearing more inside, the trailer load is too heavy.
How Does Incorrect Tire Pressure Cause Uneven Tire Wear
Having your tires inflated to the correct pressure for the load is critical as under- or overinflating your trailer tires will cause them to wear unevenly. Check the maximum tire pressure for the trailer tires so that both the tires and the trailer can handle the load capacity.
If you have one underinflated tire, that will cause the trailer load to prefer that lower side due to gravity and affect the second tire wearing unevenly. Trailer tires wearing out on both inside and outside could point to underinflation.
To Prevent Uneven Tire Wear, Check The Tire Load Capacity
Another cause of uneven trailer tire wear is when the load exceeds the tire’s load capacity. This will have the same effect on the tires as an overloaded trailer, even if the trailer is not.
For example, if you have a tandem trailer with a gross load weight of 2000 lbs, each of the four tires would need to bear 500lbs each. Each tire has a Rated Load Range, which indicates the load range that each tire can safely handle.
Suppose you have a 3000lbs trailer with two wheels, and each tire is only rated at 1200lbs Rated Load. In that case, your actual capacity is only 1200 lbs, and fully loading the trailer to the axle capacity and not the tire capacity will cause uneven wear.
You should always know the maximum load on the trailer and then ensure that the trailer tires you choose can handle that load, plus a bit extra to be on the safe side.
It’s also advisable to run horses for courses here and use Special Trailer (ST) tires designed to carry the load of the different kinds of trailers. Light Truck tires have different structures designed for carrying people, as are the standard vehicle tires.
Uneven Tire Wear Could Be Caused By Damaged Suspension
Any part of the trailer suspension system is damaged, like bent or broken struts, you will see uneven tire wear. Bent spindles or axles can all cause the tires to wear unevenly, and if you suspect this may be the case, then you should get them checked.
A damaged suspension system will also cause the trailer to bounce while in motion, affecting the towing vehicle in terms of handling, cornering, and braking. Any damaged suspension components should be replaced, and then the wheel alignment should be checked to ensure proper camber when the trailer is under load.
If you have hit a pothole and then find that there is uneven wear on the tires, this is a good indication that there could be an issue with the suspension or that one of the wheels is bent.
What Are Other Causes Of Uneven Tire Wear On Trailers
Besides all the possibilities above, other causes for uneven tire wear can be :
- Faulty or failing wheel bearings that will cause wheels to run unevenly
- The axle bow has flipped, meaning that instead of facing upwards, it’s facing downward
- Exceeding the speed rating of your trailer tires
- Flat spots on the tires caused by parking the trailer in one spot for an extended period
- Poorly balanced tires
- An unbalanced load where load weight is more to one side than the other
- Uneven towing where the trailer is pointed up or down on the back or front
As you can see, there are a fair number of reasons why your trailer tires would wear unevenly, and quite a few of them can be resolved with little or no expense and some time taken to ensure the tires are matched to the task.
When you have been through the list above and still find uneven wear, it may be time to consult a professional to determine the cause, as there is always time to make sure you are towing safely.