Product information
Trailer vs. Semi-Trailer: Definitions, Differences, and Buying Tips
In road transport, trailers and semi-trailers are familiar vehicle types that play a vital role in moving goods from one place to another. However, not everyone distinguishes these two correctly. To understand “What is a trailer? What is a semi-trailer?” and the importance of both product lines in today’s transport systems, please explore the guide below.
What are trailers and semi-trailers?
Trailers and semi-trailers are non-powered road vehicles engineered with robust structures, purpose-built to carry people or goods and to be coupled to a towing vehicle (tractor). “Trailers and semi-trailers” are also known as “full trailers and semi-trailers.”
What is a trailer?
A trailer is a towed vehicle whose total weight is not imposed on the tractor. Common trailer types include:
- General-purpose trailer – built and equipped to carry goods.
- Caravan – designed as a mobile living accommodation.
- Special trailer – engineered for a dedicated function only.
What is a semi-trailer?
A semi-trailer couples to a road tractor and transfers a substantial share of its total weight onto the tractor.
Popular semi-trailer types:
– General-purpose semi-trailers: structures and equipment for carrying goods.
– Specialized semi-trailers: purpose-built for specific cargoes, such as log carriers, low-bed semi-trailers, or fire-fighting semi-trailers.
Trailer vs. semi-trailer
Similarities
– Non-powered road vehicles towed by a motor vehicle.
– Used for freight transport.
– Common across transport networks.
Trailer vs. semi-trailer
Key differences
| Feature | Trailer | Semi-trailer |
| Axle layout | Axles at the front and rear of the trailer | All axles positioned at the rear section |
| Load transfer | Little to no weight is transferred to the towing vehicle | A significant portion of total weight is supported by the tractor–semi-trailer combination |
| Free-standing | Can stand on its own | Cannot stand without support |
| Towing vehicle | Can be towed by various vehicles | Must be towed by a road tractor |
| Typical use | Short-haul moves in plants, ports, stations, depots | Long-haul freight |
| Examples | Cargo trucks with trailers, passenger vans with trailers, ambulances (with trailers) | Container semi-trailers, tipper (dump) semi-trailers |
Popular semi-trailer categories on the market
Below is a summary of the most popular semi-trailer categories on today’s market, grouped by use case:
Container semi-trailers
Container semi-trailer – the most common type; carries one or more ISO containers moved by sea, rail, and road. A container semi-trailer can be hauled by a road tractor and carry one or more containers.
Container semi-trailer
Tipper (dump) semi-trailers
Tipper (dump) semi-trailers are used for loose commodities such as sand, gravel, or grain. The bed opens and lifts to discharge the load.
Enclosed/cage semi-trailers
Enclosed/cage semi-trailer – protects fragile or high-value goods with a surrounding steel frame.
Flatbed semi-trailers
Flatbed semi-trailer – moves oversized machinery, trucks, etc.; features a flat deck that can be tarped.
Tank semi-trailers
Tank semi-trailer – transports liquids such as oil, gasoline, or chemicals in a large tank.
Inside a Thaco Trailers semi-trailer
Thaco Trailers is a well-known Vietnamese brand producing skeletal, flatbed, and specialized semi-trailers to international standards and exporting to demanding markets such as the US, Australia, and Canada.
Axles, rims & tires
- Rim/tire sets: 8.25×22.5 with 11R22.5 (tubeless); 9.00×22.5 with 12R22.5 (tubeless); 8.00×20 with 11.00R20 (tube-type).
- FUWA axles, 13-ton rated.
Suspension
FUWA suspension with straight spring seat and 4- or 7-leaf spring reduces trailer hop during braking versus curved hangers and improves braking effectiveness and operational safety.
Main beams
High-strength Q345B steel; surface treated by shot-blasting and ED e-coating (electrophoretic coating) for durability; beams are rigidly connected to form a robust frame.
Landing legs (landing gear)
FUWA or Shutsu; 28-ton dynamic and 80-ton static load ratings.
Kingpin
Detachable kingpin 50 mm or 90 mm, selected to match payload and the tractor’s fifth-wheel specification; bolted for easy replacement.
Braking system
Pneumatic (air) brake system interfaced with the tractor.
Electrical system
Seven-pin harness powering front, side, and rear lamps; combined brake/indicator/fog/reverse lamps and license-plate light; 10–30 V operating range.
Locks (container twist locks)
Locking devices secure the trailer to the tractor and, for container models, secure containers. Layout and quantity vary by model.
Other components
THACO Trailers semi-trailers are additionally equipped with side and rear guards, a toolbox, and a spare rim/tire set for operations.
Thaco Trailers – Vietnam’s leading semi-trailer manufacturer
Thaco Trailers – a subsidiary of THACO INDUSTRIES — is among Vietnam’s leading semi-trailer manufacturers, with annual capacity up to 30,000 units. The product range includes:
– Skeleton semi-trailers: Including 20’ skeleton semi-trailers, 40’ skeleton semi-trailers, 45’ skeleton semi-trailers… This is a main export product for THACO INDUSTRIES.
– Flatbed semi-trailers: Including low-bed semi-trailers, 40′ flatbed – 3 axles – 08 twist locks semi-trailers, 45′ flatbed – 3 axles – 10 twist locks semi-trailers, etc.
– Specialized semi-trailers: Including specialized semi-trailers for the automotive sector, livestock carriers, refrigerated semi-trailers… custom-designed to specific customer requirements.
THACO Trailers – Vietnam’s leading semi-trailer manufacturer
The production lines are invested synchronously, meeting the ISO 9001:2015, ISO 14001:2015 quality management system certification. The company operates according to a closed production process, with modern technologies such as: slitting line, fiber laser cutting machine, CNC pressing machine, automatic welding robots, SEMI trailer chain turning equipment, shot blasting booth, ED coating line, automatic powder coating robot assembly line, and inspection line.
THACO Trailers supplies semi-trailers to many international partners. Products meet export standards for the U.S., Australia, Canada, Mexico, Thailand, and more. The company continues expanding exports with the goal of becoming ASEAN’s leading semi-trailer manufacturer.
Outstanding features of THACO Trailers semi-trailers:
- International-standard quality and superior durability
- High payload capacity, suitable for many types of goods
- Reasonable price
- Diverse models tailored to customers’ specific needs
Factors to consider when choosing a semi-trailer
When selecting a semi-trailer, consider the following:
Purpose of use
First, define the use case clearly. Semi-trailers move various cargo types, including containers, bulk goods, oversized loads, and fragile items. Choose the right semi-trailer type based on the cargo.
Payload capacity
Payload capacity is an important factor to consider when choosing a semi-trailer. The semi-trailer must be able to withstand the maximum payload capacity suitable for the type of goods to be transported. If the payload capacity of the semi-trailer is not enough, it may lead to accidents or damage to the goods.
Size
The size of the semi-trailer also needs to be considered in accordance with the tractor. The semi-trailer must be of the appropriate size to be pulled by the tractor. In addition, attention should be paid to the length of the semi-trailer to ensure that it does not exceed the allowable length of the tractor.
Quality
Select high-quality materials and construction to ensure durability and safety.
Price
Pricing varies by semi-trailer type, quality, size, brand, and more. Balance budget with performance and lifecycle value.
Notes when choosing a semi-trailer
Today, THACO Trailers is a leading and trusted semi-trailer manufacturer in Vietnam. With a team of 1,000 engineers and experts, the company continually improves product and service quality to deliver optimal value to customers.
