the best way to load a reefer trailer

• How do Reefer Trailers Work?
• Why Proper Loading is so Important
• Signs of an Improperly Loaded Trailer
• Reefer Trailer Loading Checklist
• How to Properly Load a Reefer Trailer Step-by-step
• Load Distribution and Weight Management
• Maintaining Airflow and Temperature Integrity
• Common Mistakes to Avoid
• The Role of Rollertrack Systems in Reefer Loading
• Frequently Asked Questions (FAQs)

How a Reefer Trailer Maintains Temperature Control

Standard reefer trailers feature insulated walls, a floor, ceiling, refrigeration unit, air circulation system and temperature-monitoring sensors or devices. You’ll also find a compressor and evaporator. The trailer controls the temperature as follows:

1. The compressor pressurises the refrigerant, which causes the refrigerant’s temperature to increase.
2. The hot refrigerant travels through the condenser and releases heat to the outside air.
3. The cooled refrigerant goes through an expansion valve, which reduces its temperature even more.
4. Cold refrigerant flows through an evaporator and absorbs heat from the inside of the trailer.
5. Fans circulate the cold air throughout the reefer trailer so that it maintains the desired temperature.

Proper loading of any truck trailer, not just reefer truck ones, is essential. Improper loading can cause accidents because the vehicle can become more difficult to manoeuvre and to brake. Cargo can shift while the truck is moving. It also places wear and tear on tires, which may overheat and experience issues during journeys, and the driver may misjudge their vehicle’s ability to stop. It can also affect the level of contact of the tyres with the road if too much weight or too little is on one of the axles.

In the context of reefer trucks, improper loading by not following loading practices can cause additional problems such as hot spots, spoilage of goods and, due to the damage of the goods, claims against businesses.

Claims

Improper loading can not only damage the goods and/or cause them to spoil, but it also inflicts financial damage. Angry customers may subject claims against you. You may also face financial penalties for not complying with regulations around temperature control. In addition to this, delivering spoiled or compromised goods could harm your reputation.

Improperly loaded trailers can create dangerous situations on the road, damage the vehicle and cause delays, so it’s essential to be able to recognise an improperly loaded tailer.

How to tell if your trailer is overloaded or unbalanced

Your vehicle or the load will give you clear signs if they’re unbalanced or you’ve overloaded it:

• The towing vehicle will sway from side to side because the overloading is causing the trailer to pivot on the towbar;
• The drawbar on the towing vehicle will be heavy to lift because the trailer is unbalanced too far to the front;
• The drawbar will be too easy to lift, or in extreme cases, the rear of the trailer is tilted to the ground, because the load is too far back;
• The sides will bulge, which suggest the cargo isn’t properly secured and is pushing against the walls;
• Loose or absent straps, which suggest the load has shifted and/or isn’t securely fastened;
• The trailer is unlevel: the nose is up, which suggests it’s riding too high, or down, which suggests too low.

An overheated axle after a long haul is another sign of trailer overloading. As time goes by, you may also notice uneven tire wear patterns, another warning you could be overloading your trailer.

Before loading

• Pre-cool the trailer to stop excess heat from transferring through the walls. Bring it to target temperature before loading.
• Turn off the refrigeration unit to stop the fan drawing warm into the trailer.
• Inspect the trailer for any damage that could compromise the temperature, including the side walls, ceilings and doors. Check the air chutes and seals are intact.
• Clean, sweep and sanitise the trailer. Remove any debris.
• Pre-cool the goods to the desired temperature before loading.

After loading

• Seal and close doors quickly to reduce air loss.
• Check the load for proper airflow
• Check all bulkheads, straps, load locks and other load-securing equipment is secure.
• Verify the temperature and unit mode: continuous is best for fresh produce and pharmaceuticals, whereas cycle mode is acceptable for frozen goods, but if in doubt, choose continuous mode.
• Monitor temperature and conditions and document them for load compliance. Use temperature sensors and real-time monitoring systems to track trailer conditions.

Understanding axle balance and legal weight limits

Always check the towing vehicle’s load capacity and the trailer’s load capacity. Respecting axle balance and legal weight limits is essential for safe loading and transportation. Both the operator and the driver are liable for penalties if a loaded vehicle exceeds the limits displayed on the manufacturer or ministry’s plates. 

On its website, the UK Government sets out clear maximum gross weight limits, plus definitions and specific circumstances, for vehicles as below:

British regulations also set out weight limits per axle, based on the types of axles, vehicles, number of axles and space between axles.  

Using load sensors or automation to verify even weight

Logistics operators don’t have to load completely in the dark when it comes to knowing whether they’re overloading or not. They can weigh loads with onboard weighing equipment and automated technology that uses load sensors to measure load weights in diverse aspects, such as weight per axle, load weight and gross weight.

These pieces of technology detect potential overloads, some by monitoring degrees of body lean to the left and right, and provide automatic alerts of any overload. Some systems also issue automatic notifications if weight changes, which indicate the load may have shifted and isn’t secure, or if there has been possible tampering with the load, detected through unusual sensor activity.

Air chute and bulkhead use in multi-temp trailers

Not all reefer trailers maintain the same temperature throughout the entire trailer like single-temperature reefers do. Multi-temperature reefers use bulkheads to divide goods into compartments set at different temperatures so users can transport different goods all in one trip. A typical example of this is dividing the trailer into fresh goods in one part and frozen in another. This helps businesses save on their costs.

Multi-temp trailers also contain air chutes. Often, these are fitted to the ceiling of a reefer trailer unit and run to the back of the trailer, ensuring air from the refrigeration unit reaches the back and flows evenly throughout the trailer. Air chutes are often compatible with movable bulkheads to work within multi-temp trailers.

Overloading the trailer

A reefer trailer isn’t like a dry van, and lots of operators pack the trailer so tightly the goods touch the walls. That’s a big mistake. Air must be able to flow around the sides, underneath the goods and across the top.

Blocking airflow with packaging

Always load cargo into trailers on pallets so air flows underneath the goods. Flat boxes should never be loaded directly onto the floor. Be sure, too, to secure the cargo. If not, it can shift and create blockages that obstruct airflow.

Mixing frozen and chilled items in single-temp trailers

Mixing items in single-temp trailers is more likely to cause quality issues, so multi-temperature trailers are better if you’re transporting a mixture of fresh and frozen goods. You should separate the goods with one or more bulkheads to prevent cross contamination.

Rollertrack systems can support your reefer trailer loading. Their loading speed, precision and efficiency can keep things moving swiftly to reduce the risk of cargo spoiling. Explore our Truck Loading Solutions to see how they improve speed, safety, and cargo protection.

How rollertrack floors improve loading consistency and protect cargo integrity

Our Rollertrack systems allow consistent cargo loading in trailers. These are:

• Built-in Rollerbed System
• Modular Rollerbed System: Block Pallet
• Modular Rollerbed System: Air Cargo
• Powered Cargo Roller

All Rollerbed Systems are designed to handle pallets or air cargo. Each system allows logistics personnel to load large amounts of cargo into trailers quickly and safely, and since it’s possible to roll cargo into the trailers, forklifts have much less chance of piercing the cargo and damaging the load, so goods can arrive intact. Systems like the Modular Rollerbed with Powered Cargo Rollers also make it easier to position ULDs, again reducing the risk of damage.

Similar principles apply in air cargo, where temperature-sensitive goods are transported in Unit Load Devices, learn more in our guide to What a ULD is and How to Load and Unload Air Freight.

We can also customise these systems, which we can retrofit in standard trailers and which operators can transfer from one trailer to another, in line with the types of loads you’re carrying. For load stability, pallet stops are a standard part of each MRS so that cargo can’t slide out of the back of the trailer.

With over 60 years of experience in loading and unloading solutions, Joloda Hydraroll systems are used globally across logistics, air cargo, and cold-chain operations.

Minimising door-open time and thermal shock with fast, safe loading

The quicker you can load the goods into a reefer trailer and close the doors, the better. Rollerbed systems enable you to load reefers with large volumes of goods in just a few minutes, allowing you to shut the doors as soon as possible, minimise thermal shock and preserve cargo.

What temperature should a reefer trailer be set at?

The correct temperature depends on the cargo type:

• Fresh produce: 0°C to 4°C
• Frozen goods: -18°C or lower
• Pharmaceuticals: typically 2°C to 8°C

Always pre-set and stabilise the temperature before loading, as reefer units are designed to maintain temperature.

How do you properly load a reefer trailer?

To properly load a reefer trailer, pre-cool both the trailer and cargo to the required temperature before loading. Load quickly and keep doors closed to prevent heat ingress. Leave space around pallets to allow airflow, avoid blocking floor vents, and follow the 60/40 weight distribution rule (60% front, 40% rear). Secure all cargo with load locks or straps to prevent shifting and ensure consistent temperature throughout the journey.

How do you load a reefer container differently from a trailer?

A reefer container is loaded using the same core principles as a reefer trailer: pre-cooling, airflow, and load securing, but requires stricter airflow management due to its sealed design. Cargo must not block the T-bar floor, which distributes cold air, and spacing between pallets is critical to prevent hot spots. Containers are typically loaded for intermodal transport, so stability and tight securing are even more important to withstand multiple handling stages.

How do reefer trailers work?

Reefer trailers work by using a refrigeration unit to remove heat from the trailer and maintain a set temperature. A compressor pressurises refrigerant, which releases heat through a condenser before cooling further in an expansion valve. The cold refrigerant then absorbs heat inside the trailer via an evaporator, while fans circulate cold air evenly around the cargo to maintain consistent conditions.

Is a reefer trailer the same as a refrigerated trailer?

Yes, a reefer trailer is the same as a refrigerated trailer. “Reefer” is simply industry shorthand for a temperature-controlled, insulated trailer equipped with a refrigeration unit used to transport perishable or temperature-sensitive goods.