Overlander Trailer Axle: Timbren Axle-Less Suspension

While frame selection is critical, choosing the right overlander trailer axle is also a key component for a number of reasons.

First, your axle selection is going to dictate (for the most part) the weight your trailer can carry. For those that are not aware, there are several terms to be aware of and they are as follows:

GVW

Gross Vehicle Weight. This is your vehicle’s standard curb weight, plus an estimate of the typical load of passengers, fuel and stuff.

GVWR

Gross Vehicle Weight Rating. This is the maximum safe weight for your vehicle. Exceeding this weight will place stress on your engine, transmission, and brakes beyond what they are designed for.

Tongue Weight

The amount of weight at the coupler (where the trailer meets the vehicle).

GCW

Gross Combination Weight. This is the combined weight of your vehicle and the trailer (Not the tongue weight, but the total weight.) This number cannot exceed the GCWR.

GCWR

Gross Combination Weight Rating. This is the maximum safe weight of your vehicle and trailer when both are fully loaded with people, fuel, and all your stuff. And like the GVWR above; exceeding this weight will place stress on your engine, transmission, and brakes beyond what they are designed for.

GAW

Gross Axle Weight. This is the amount of weight that carried by each of the vehicle’s axles. They will be different based on engine weight and trailer tongue weight capacity.

GAWR

Gross Axle Weight Rating. This is the maximum safe weight you can place on the front and rear axles. And just like the other two weight ratings above, exceeding these numbers will damage your vehicle and create dangerous driving conditions.

Source: https://www.4wheelparts.com/the-dirt/towing-your-trailer-determining-the-towing-capacity/

All vehicles have a towing capacity as well as tongue weight restriction so will want to find out what yours is before you get too far down the road with your build.

In our case we will be pulling our trailer with either a GMC Canyon pickup or a Subaru Ascent SUV. Believe it or not, the Subaru Ascent can tow 5,000lbs and has a tongue weight max of 500.

The Ironton trailer frame we purchased actually comes with an axle that allows for 1,715lbs, which is decent for a trailer that is not going to have sleeping arrangements or a roof top tent. However, it was still going to be too close and we wanted to create a trailer that was truly off-road capable and a through axle would certainly complicate that without the right lift set up.

Enter the Timbren Axle-less suspension system. These come in a variety of configurations to meet various needs and budget requirements. Though as I right this, we have not actually tested them yet, having installed them I can say with absolute certainty that these things are BURLEY and far more substantial than the axle that came with the trailer kit.

We opted for the Heavy Duty version that provides a load capacity of 3,500lbs, will accommodate larger off road tires, and gives and additional 4″ of lift and we got a great deal on them through etrailer.com.

A few things to note with these:

Watch the video on etrailer.com on how to install these and read the instructions provided by Timbren. It’s a very straight forward process, but does require some precision.
While some do come assembled, ours did not and required the spindles to be bolted on first (the bolts are provided). This requires a torque wrench which can be purchased at Lowes for about $90 – you will also need it when attaching the axles to the frame.
Depending on your trailer build, you may find it much easier to flip the trailer over when installing them. Since our trailer was only in a frame state, it was easy to turn it over. This allows the axles to rest flush against the bottom of the frame vs. having to hold them in place when trying to measure and drill the mounting holes in the frame.
While our trailer did have the support crossmembers directly below the axle (as Timbren mentions in the install directions), we decided adding the steel tubing wouldn’t hurt. So after getting the axle system loosely bolted to the frame, we measured the distance required for the tubing and found 5′ would work (seems about right since it’s a 5×8′ trailer). I was able to find a piece of steel at a local weld shop and had them cut it to length for $25 – which was half the price I was able to find online.
Once you have everything together and bolted firmly down, you will likely need some help flipping the trailer back over – like I said, these things are BURELY!