Semi-trailer types and what they're used for

1. Flatbed trailer

Flatbed trailers offer versatility and are therefore some of the most commonly used trailers. The name derives from the fact that flatbed trailers have a flat deck that is open on all sides, with no roof or box to cover the load. This open layout makes it an easy trailer to load and unload, but does not protect the cargo from weather and road factors. Flatbed trailers are ideal for carrying wide or large loads because the goods can be lifted from above with a crane or lifted from the side with a forklift.

Flatbed trailer Typical cargo type:

Building Materials

Heavy equipment and machinery

Oversized or abnormally shaped loads

wood

Legal load specification of flatbed trailer:

* Maximum cargo weight of flatbed trailer :48,000 LBS

* Maximum cargo size of flatbed trailer:

Maximum trailer length :48 feet - 53 feet

Maximum trailer width :8.5 feet

Maximum legal cargo height :8.5 feet

2. Step deck or drop deck trailer

Step deck trailers, also known as drop deck trailers, are similar to flatbed trailers in that they are an open trailer, but there are some differences. Flatbed trailers have only one level, step deck trailers have two levels of deck, known as upper deck and lower deck.

The upper deck is between 10 and 13 feet in length and sits above the tractor unit. The lower deck is between 38 and 40 feet in length and only 3 feet 3 inches off the ground. This lowered deck provides stepped deck trailer capability to haul higher loads.

Step deck or hanging deck trailer Typical cargo types:

Tall cargo over the legal height limit on a conventional flatbed trailer

Legal load specifications for step deck or hanging deck trailers:

Step deck trailer maximum cargo weight :48,000 LBS.

Maximum cargo size of step trailer:

Maximum trailer length :48 feet - 53 feet.

Maximum trailer width :8.5 feet.

Maximum legal cargo height :10 feet.

3. Dump Trailers

Dump trailers are a type of hauling trailer that use hydraulics to lift the trailer bed up and tilt it to unload heavy hauls with ease and the help of gravity. Although dump trailers are oftentimes confused with dump trucks, dump trailers allow you to customize the trailer size to correspond to your load. Dump trailers are less expensive than dump trucks but still offer the ability to haul heavy payloads safely and efficiently.

You’ll find dump trailers are available with a frame or frameless. Frameless dump trailers allow for heavier payloads because they’re made of aluminum and are lighter weight. Steel frame dump trailers are a great choice for larger hauls, like equipment and large boulders.

Another thing to consider when selecting a dump trailer is the style of dumping. It’s helpful to compare end dump vs. side dump vs. bottom dump trailers so you know which one is the right one for your project.

Dump Trailer Typical Cargo Types:

· Gravel

· Sand

· Stone

· Fill dirt

· Trash

· Branches

Dump Trailer Legal Load Specifications:

Dump Trailer Maximum Freight Weight: Dependent on local regulations

Dump Trailer Maximum Freight Dimensions:

Maximum Trailer Length: 45 feet

Maximum Trailer Width: 8.5 ft.

Maximum Legal Trailer Height: 13’6”

4. End Dump Trailers

End dump trailers operate the same way most dump trucks do and unload cargo out of the rear of the trailer while the front of the trailer is lifted into the air. Because the load is shifted out of the bed of the trailer by gravity, the front of the box needs to be lifted high enough to encourage this movement to happen. This raised position lends itself to some instability and may be worsened by uneven ground or shifted loads. End dumps are not used to haul liquids because it’s difficult to make the rear gate watertight.

5.Side Dump Trailers

Side dump trailers are a newer concept developed to resolve the instability issues of end dump trailers. By tilting the trailer to one side to unload cargo, side dump trailers offer greater stability regardless of even

and uneven ground. Side dump trailers allow operators to safely haul and release a variety of materials with a more rapid dump cycle.

6.Bottom Dump Trailers

Bottom dump trailers, also known as belly dump trailers, unload material directly from the bottom of the box. Most models today use a “clam shell” type of dump gate so that the contents can be windrowed, or released in a low ridge, long line instead of a single pile. Bottom dump trailers are not suitable for all types of materials considering fine material and liquid will likely leak out and the axles of the trailer must be able to clear the windrow.

7. Tanker trailer

Tank truck trailers are usually used to transport liquids and are made of aluminum or stainless steel. Due to their unique shape, tank truck trailers are cylindrical, and for good reason. The tank car has a cylindrical construction because it reduces pressure on the tank itself, provides a lower center of gravity, prevents fluid from surging, and is easier to extract and clean.