Buying a semi-trailer: what should you pay attention to?
A semi-trailer must match the cargo, tractor unit, loading locations, and routes. Body type, payload capacity, flooring, axles, and fifth-wheel height determine whether the combination can be operated safely and efficiently in practice.
Therefore, do not just check the brand, year of manufacture, and price. A semi-trailer with the correct overall dimensions can still be unsuitable due to the loading aperture, floor load capacity, kingpin position, unladen weight, or missing equipment.
Which semi-trailer type suits the cargo?
A curtainsider is flexible when loading frequently from the side with a forklift. A box body offers more protection against weather and unauthorized access. For chilled or frozen goods, insulation, air distribution, temperature recording, and the capacity and maintenance condition of the cooling unit are important.
Container chassis must match the container sizes and twistlocks used. For machinery and heavy equipment, loading floor height, ramp angle, floor load capacity, lashing points, and available width are decisive. A tipper, walking floor, or tanker also requires appropriate hydraulics or other connections on the tractor unit.
Fifth-wheel height and tractor connection
Fifth-wheel height, kingpin height, and kingpin position determine whether the combination is level and has sufficient clearance. When coupling, check the clearance to the cab, chassis finish, and mudguards, both when driving straight ahead and during tight turns and height differences.
Also check air lines, electrical connections, braking system, and any hydraulic couplings. A volume trailer may require a low tractor unit and non-standard tire size, while specialist trailers may need additional chassis space or controls.
Payload, axles, and weight distribution
The payload capacity follows from the permissible gross weight minus the actual unladen weight including fitted options. Spare wheel carriers, taillifts, truck-mounted forklifts, cooling units, and extra storage boxes reduce the remaining cargo capacity.
The position of the cargo determines how much weight rests on the kingpin and individual axles. A lift axle can limit tire wear and rolling resistance during light loads. A steered axle improves maneuverability in tight locations, but adds components and maintenance. Always check whether the selected configuration matches the tractor unit and typical load.
Floor, doors, and loading equipment
Inspect the floor for wear, moisture, repairs, and localized deformation. The specified floor load capacity must match the forklifts, pallet jacks, and concentrated loads encountered in daily operations. Also check lashing rails, stake pockets, and fastening points.
Doors, curtains, sliding roof, and lifting roof must operate smoothly over their full range. For a taillift, platform size, lifting capacity, controls, leaks, and maintenance are relevant. Measure the clear loading aperture; external and internal height do not automatically indicate how much clearance is available at the doors.
Inspecting a used semi-trailer
Inspect the chassis and crossmembers for cracks, corrosion, deformation, and previous repairs. Check axles, bearings, brakes, tires, air bellows, landing legs, lighting, and the electronic braking system. Uneven tire wear may indicate alignment or axle issues.
In addition, test all specific bodywork technology, such as the refrigeration unit, hydraulics, walking floor, tipping cylinder, or container locks. Maintenance and inspection records are an essential part of the purchase inspection for specialist trailers.
Comparing new and used semi-trailers
On TruckTrader you can compare semi-trailers by brand, type, year of manufacture, body style, number of axles, and configuration. Ask the seller for exact dimensions, weights, maintenance information, and documentation for any loading, cooling, or hydraulic systems present.
For example, view Schmitz Cargobull trailer, Krone trailer, Pacton trailer, Wielton trailer, Floor trailer and Lecitrailer trailer and then verify whether the specification matches your tractor unit and cargo.
Looking for a tractor unit or another transport vehicle?
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