subject: Semi - Trailer or Truck Trailer - Explanation and Definition [print this page] Semi - Trailer or Truck Trailer - Explanation and Definition
A semi-trailer (also known as atruck trailer) is a type of over-the-road freight vehicle that does not have a front axle. Semi-trailers are pulled by truck-tractors. A large proportion of a semi-trailer's weight is supported by the road tractor or by a detachable front axle assembly called a dolly. A semi-trailer is equipped with legs, called dolly legs, that can be lowered to support it when it is unhooked from the tractor. When coupled together, the tractor and trailer combination is often referred to as a semi, 18-wheeler, big-rig, articulated lorry, or truck and trailer.The purpose of a semi-trailer is to carry freight. The majority of products are transported in semi-trailers. Truck trailers are sold by manufacturer owned and independent dealerships.
Common Types of Trailers
Types include dry freight vans, refrigerated vans (reefers), flatbeds (straight platform, step-deck, lowboy, double drop, etc.) and tanks. Sizes vary, but the most common sizes in use today are 53' or 48' in length; 102" or 96" in width; and, up to 13'6" in height. Typically, trailers carry 45,000 lbs. of freight.
A flatbed is non-enclosed with no sides, no roof and no doors. Flatbed trailers can be loaded or unloaded from the sides, and they do not require an elevated forklift for load entry or removal. Flatbeds are also referred to as Platform or Deck trailers. Varieties include standard straight floor flatbeds, drop decks, lowboys and other specialized flatbeds.
A dry van is a fully enclosed vehicle. It is the most common type. Standard varieties include Sheet & Post Construction and Plate Construction. Dry vans are also known as dry boxes.
Vans used for hauling products requiring temperature controls are known as Refrigerated Vans or Reefers. Reefers are insulated in the nose, sides, roof and floor. A refrigeration unit is mounted on the nose. Reefers are capable of maintaining below zero temperatures.
For more information about semi-trailers, please see American Trailer Exchange
