For transporting construction machinery, the trailer is chosen according to the machine's transport height, operating weight and type of undercarriage. Light, low machines are carried on a flatbed with ramps or a semi-lowbed trailer; tall and heavy excavators and dozers need a lowbed trailer. The aim is to keep the total height including the load below the 4.00 m limit and to distribute the axle loads evenly.
Which measurements determine the choice of trailer?
Three pieces of information are needed to find the right trailer: the machine's height in transport position, its actual operating weight including attachments, and its widest point. Article 128 of the Road Traffic Regulation (Karayolları Trafik Yönetmeliği) sets limits of 2.55 m width and 4.00 m height including the load; for combinations with five or more axles, the total weight is limited to 40 tonnes. An indivisible load exceeding any of these dimensions may only go on the road with a special permit from KGM (General Directorate of Highways). All the limit values are listed in the entry legal road dimension limits.
The weight in the catalogue is often given with a standard bucket and boom. A hydraulic breaker, a long boom, additional counterweight or mud built up on the tracks can make a difference of several tonnes. The dimensions and weight should therefore be stated as the machine will be loaded.
Which trailer suits which machine?
| Machine | Typical trailer | Point to watch |
|---|---|---|
| Mini excavator, backhoe loader, forklift | Flatbed with ramps or semi-lowbed | Ramp gradient, tyre and track slippage |
| 20–30 tonne tracked excavator | Semi-lowbed or well-deck lowbed | Height of the folded arm and cab |
| Dozer | Lowbed | Blade width exceeds 2.55 m on most models; the blade can be carried separately |
| Grader, roller | Semi-lowbed or lowbed | Length and front-rear overhang on a grader |
| Excavator over 40 tonnes, crawler crane base | Multi-axle lowbed with detachable gooseneck | Counterweight and boom on a separate vehicle |
| Long-boom drill rig, piling rig | Extendable lowbed | Marking of the rear overhang |
The choice often comes down to a few centimetres. A dozer with a transport height of 3.15 m rises to 4.05 m on a semi-lowbed with a 0.90 m deck and exceeds the limit. The same machine stays at 3.85 m on a lowbed trailer with a 0.70 m well. For lighter and lower machines, on the other hand, a semi-lowbed is both easier to find and more economical.
How is a machine loaded onto the trailer?
- Ground and ramp check: The trailer stands on level, firm ground, and the ramps are set at an angle suited to the machine's climbing ability. Mud, oil and ice are cleaned off the ramps and deck.
- Driving on under its own power: The operator drives up at low speed in a straight line, guided by a banksman from below. No steering corrections or slewing of the upper structure are made on the ramp.
- Positioning: The machine's centre of gravity is placed relative to the axle group; a load shifted forward or backward overloads a single axle even if the total weight is within limits.
- Securing the arm and bucket: The arm is folded, the bucket is lowered onto the deck and supported with chocks. The upper structure swing lock is engaged, the parking brake is applied and hydraulic pressure is released.
- Lashing: The machine is chained in at least four directions from the lashing points indicated by the manufacturer. Removed buckets, blades and attachments are secured separately. The required force is found with a lashing calculation according to EN 12195-1.
- Final measurement: After loading is complete, the highest point on the cab, exhaust, beacon and arm is measured again. The actual dimension is compared with the dimension in the permit.
Who is responsible for what?
The shipper provides the correct dimension and weight information for the machine and a document showing the lashing points. The carrier provides a suitable trailer, lashing equipment and the necessary permits. The machine is usually driven onto the trailer by the shipper's operator; the division of roles during loading should therefore be agreed in writing in advance.
Common mistakes
- Relying on the catalogue weight and not accounting for a breaker or additional counterweight.
- Leaving the bucket raised, or carrying material inside the bucket.
- Setting off without cleaning the mud off the tracks; falling mud creates both a weight and a traffic risk.
- Declaring the height based on a pre-loading estimate, so that the permit dimension and the actual dimension do not match.
How does Voltim Global support you?
For construction machinery shipments, Voltim Global handles trailer selection, the lashing arrangement and oversize and heavy load permits in a single plan. On the Voronezh–Mersin shipment, it obtained the KGM special permit in 1 day.