They also have a natural upwards bend so that when loaded they straighten out to be flatter rather than to sag in the middle under a load. Incredibly light and very expensive to purchase, all-aluminum trailers are very slippery when wet. Which is the lightest allowing for more cargo to be legally carried without overweight permits. These types often have a wood portion for nailing down dunnage boards, and aluminum. The ever-popular combo with a steel frame and aluminum bed. Body and frame can be one of 3 general designs: the heaviest and sturdiest is all steel, usually with wood planks. Several lengths and combination setups can only be legally driven on turnpike/toll roads which are far too long for most roadways. Some older trailers are only 45 feet or shorter if used in sets of doubles or triples, often used to haul hay. Including rub rails and stake pockets on the sides, which generally placed every 2 feet. The length is either 48 feet or 53 feet, and the width of 96 or 102 inches. Types of Trailers Flatbed Trailerįlatbed trailers are the most popular and common of the semi-trailer use today. Read below for a list of the different types of trailers for semi-trucks. The first semi-trailer is connected to the power unit using the tractor’s fifth wheel coupling while the converter dolly, already attached to the second semi-trailer, is connected to the first semi-trailer with a drawbar. A double-trailer combination is possible with the use of a dolly, or “converter dolly”, essentially one to three additional axles placed under the front of a second semi-trailer. Other terms used are “ B-train ” or (when there are three or more trailers) “ road train “. Semi-trailers with two trailer units are called tandem tractor-trailers tandem rigs or doubles. Ease of backing is cited as one of the semi’s best advantages. Many trailers have wheels that are capable of being totally dismounted and are also relocatable (repositionable) to better distribute the load to bearing wheel weight factors Semi-trailers are more popular for transport than full trailers, which have both front and rear axles. A trailer is normally equipped with landing gear (legs which can be lowered) to support it when it is uncoupled. Ī large proportion of a semi-trailer’s weight is supported by a tractor unit, or a detachable front-axle assembly known as a dolly, or the tail of another trailer. In the United States, the term is also used to refer to the combination of a truck and a trailer also called a tractor-trailer. So, what is a trailer? What are the different types of trailers for semi-trucks? A semi-trailer is a trailer without a front axle. This article will cover the different types of trailers for semi-trucks.

Semi truck and trailers