Should I Buy a Single Axle or a Tandem Axle Trailer?
One of the most common questions our team is asked is about the main differences between single axle trailers and dual axle trailers. In this blog we summarise the relative merits and benefits of each trailer type to help you make an informed choice about whether a single axle trailer or double axle trailer is going to be right for your needs.
Making sure you select the right size and type of trailer is crucial for ensuring greater stability on the road, better weight distribution and a smoother ride when towing on both roads and work sites.
How to choose the perfect trailer for your needs
One of the most important considerations when choosing a trailer is the load capacity you require.
A single axle trailer (i.e. a trailer with one axle, two tyres and two sets of bearings), will generally be suitable for carrying lighter loads over short trips, and typically has an Aggregate Trailer Mass (ATM) of 1,350 kg when fully loaded (although this can usually be upgraded to 1,600 kg or 1,990 kg if required).
For heavier loads, a double axle or dual axle trailer will generally be required. This is because tandem axle trailers have two axles and four wheels so the weight load is more evenly distributed, meaning they can handle a larger load capacity and will provide increased stability and fuel efficiency when towing on longer journeys, on rough terrain, uneven roads, or at highway speeds. Double axle trailers generally have a 1,990kg ATM as standard but this can be increased if greater weight capacity is required.
Triple axle trailers are fitted with an extra axle and two extra wheels and can have an ATM up to 4,800 kg, making them ideal for industrial and heavy duty applications when you need more interior space and to carry significantly heavier loads.
Other considerations when choosing between a single axle or tandem axle trailer
As well as the weight and types of loads you regularly carry, there are some other factors that need to be considered when making the choice between a single axle vs tandem trailer.
The compact design of single axle trailers means they generally have less weight capacity and are easier to move by hand or manoeuvre in tight spaces. As they usually carry lighter loads, single axle trailers are fuel efficient for the towing vehicle both over short distances and longer journeys.
Tandem trailers are generally larger and designed to carry more weight and heavier loads. This can mean that they need more space to store them, are more challenging to move by hand, and may not be as fuel efficient as smaller trailers. A dual axle trailer may also require more maintenance, as there are four wheels, and four sets of brakes and bearings to be serviced. However, they are more equipped for towing over long distances, and provide better stability on country roads and worksites.
When it comes to registration, however, there is no difference in cost when you register a single axle or tandem axle trailer in South Australia.
Dual axle trailers provide enhanced stability when carrying heavier loads
If you are regularly towing heavier loads, a double axle trailer delivers a number of major advantages. Most notably, the two axles provide more stability and braking power than a single axle when properly loaded, essential when you have more weight onboard, are towing over long distances, or travelling at higher speeds.
The second axle and additional wheels ensures better weight distribution and prevents trailer sway, one of the biggest risks when towing a trailer, and also makes a big difference in terms of tow vehicle fuel efficiency and when towing in rough conditions.
Understanding the maximum weight and load capacity your trailer can safely carry
When choosing between a single axle trailer or double axle trailer, it's essential to understand the weight capacity you require and whether or not you use your vehicle to regularly tow heavy or smaller loads.
As you look at different trailers, you may come across a measurement known as Gross Trailer Mass (GTM), which is the maximum permissible weight that can be supported by the wheels and axles when connected to the tow vehicle.
However, at Basic Trailers we think a more useful way of looking at trailer capacity is Aggregate Trailer Mass (ATM). This is the combined weight of the trailer and load when not connected to a towing vehicle. The ATM and the sort of load you usually haul should ultimately determine how many axles you require.
A single axle trailer will generally be sufficient for lighter loads, typically up to 1,990kg, over short trips on good road surfaces. However, for heavier loads up to 4,500kg a dual axle trailer with more wheels will likely be required.
Tandem trailers come in a variety of designs, including plant trailers, mower trailers, flat top trailers and car trailers, and offer more interior space and greater weight capacity, so are ideal for long haul jobs and carrying vehicles, heavy machinery, plant and building materials.
Choose the right trailer suspension components for a smoother ride
Trailer suspension is designed to absorb shocks from the road and minimise the force that is transferred to trailer body and cargo. This helps to maintain structural integrity, reduce tyre wear, improve fuel efficiency and produce better stability on both roads and rough terrain.
The type of suspension that you ultimately choose for will depend on the size, type and ATM of the trailer, whether you use your trailer for home or work, and the loads you mot often carry.
Slipper spring suspension
Slipper spring suspension featuring 7 leaf springs can be fitted to both single axle and tandem axle trailers. Slipper leaf springs have an eye at one end and open leaves at the other, and this forms a tail which is inserted into a hanger that's welded to the trailer chassis.
Slipper spring suspension is usually sufficient for trailers with an ATM up to 1,990 kg, but if you tow heavier loads or regularly drive on rough terrain, an upgrade will be required.
Eye to eye trailer suspension
Single axle trailers and double axle trailers with an ATM of 2,000 kg or more can be fitted with eye to eye suspension(also known as shackle or double eye suspension), which is designed to carry more load and be more durable than slipper springs.
Both ends of the spring form circular 'eyes'; the front eye is held in place by a hanger, while the rear coil swings on shackle bolts. On double axle trailers, the springs will usually be connected in the centre with a load sharing rocker beam.
Rocker roller suspension
Rocker roller suspension is a full load sharing system that is ideal for trailers up to 4,500kg ATM and towing heavier loads.
A variation on a standard rocker assembly, two of the bolted connections are replaced with roller bearings making them less rigid and able to absorb impacts more effectively. Rocker roller suspension is also very tough and durable, resulting in lower maintenance costs.
Basic Trailers single axle and tandem axle trailers
At Basic Trailers, we design and manufacture a large range of single axle and tandem trailers designed to meet ally types of everyday and heavy duty towing needs.
No matter whether you require a trailer for work or at home, and regardless of the size of load or what you carry, we have a single axle or tandem axle trailer that will get the job done. We can also design and custom build single axle trailers and dual axle trailers fitted with a variety of additional components and add-ons to suit your specific needs.
Need more assistance in deciding between a single axle or tandem axle trailer?
If you still aren't sure whether a single axle trailer or a tandem axle trailer is going to best suit your needs, we are here to help.
Call Basic Trailers on 1300 770 770, or email us with your enquiry, and a member of our friendly, knowledgeable team will be happy to discuss your precise requirements.
Single axle vs tandem axle trailers FAQs
What is the key difference between single axle and double axle trailers?
A single axle trailer has one axle with two wheels, while a double axle trailer has two axles and four wheels. Single axle trailers typically have an ATM (Aggregate Trailer Mass) between 1,350kg – 2,000 kg, while the ATM of trailers with dual axles usually starts at around 1,990 kg ATM, although this can be upgraded to as much as up to 4,500 kg if required.
When is a single axle trailer the right choice?
If you only need to carry smaller loads under 2 tonnes, or generally use your trailer for short trips to the dump or to move furniture, a single axle trailer will likely meet your needs. There is the added advantage that trailers with a single axle are easy to hitch and can be moved and stored in tight spaces.
When should I choose a double axle trailer?
If you regularly carry loads of more than 2 tonnes, have to travel long distances, or want increased stability at highway speeds, a dual axle trailer will be the best choice. The extra axle and four wheels provide a smoother ride, better stability and less risk of trailer sway, plus there is enhanced brake capacity and less potential danger from a puncture or flat tyre. Double axle trailers are designed to suit the needs of gardeners, tradies, builders or anyone working in construction.
What else should I consider when choosing between a single axle or tandem axle trailer?
When considering whether a dual axle or single axle trailer will be right for you, factors like ATM, load weight, tow vehicle capacity, brake and suspension requirements all need to be taken into account. You should also bear in mind what sort of add-ons and additional components are available if you want to customise your trailer.
What are the brake requirements for single axle and dual axle trailers?
In Australia, single axle trailers with an ATM below 750kg do not require brakes. Any trailer with an ATM between 750kg and 2,000kg must have brakes on both wheels on at least one axle. For double axle trailers with an ATM above 2,000kg, brakes must be fitted on all wheels on both the front axle and rear axle. These are required to be electric brakes and fitted with a breakaway system that automatically apply the brakes if the trailer becomes separated from the tow vehicle.
