Tridem mechanical suspension is with three rear axles . Different types of semi-trailers are designed to haul different cargoes. Common widths are 8 ft (2.44 m), and 2.6 metres (102.36 in). Generally speaking, most North American type trailers use two axles with dual-tire hubs totaling 8...
Tridem mechanical suspension is with three rear axles .
Different types of semi-trailers are designed to haul different cargoes.
Common widths are 8 ft (2.44 m),and 2.6 metres (102.36 in). Generally speaking, most North American type trailers use two axles with dual-tire hubs totaling 8 wheels, while most European type trailers use three axles with single-tire hubs totaling 6 wheels, with one of the axles being able to be lifted for lighter loads and saving on tire, brake, and axle wear. Nearly all sufficiently tall modern trailers are equipped with a rear underride guard to prevent cars from passing beyond the rear edge of the trailer, and most also have side underride guards for the same reason. There are also other smaller differences with regards to kingpin depth, lighting, door locks, et cetera, though most purpose-built tractor trucks can carry most types of trailer regardless of which continent it was built on and the differences therein.
● Box or van trailers are the most common type. They are quite simply a metal box on wheels with some doors on the back, though some offer additional access doors on the sides. Standard lengths in North America are 28 ft 0 in (8.53 m), 32 ft 0 in (9.75 m), 34 ft 0 in (10.36 m), 36 ft 0 in (10.97 m), 40 ft 0 in (12.19 m), 45 ft 0 in (13.72 m), 48 ft (15 m), 53 ft 0 in (16.15 m) and 57 ft 0 in (17.37 m). Due to maximum length regulations and the need to maximize cargo within said regulations, almost all European semi-trailers are 13.60 m in length (44 ft 7 & 7/16 in).
● Bus-bodied trailers are hitched to a tractor unit to form a trailer bus, a simple alternative to building a rigid bus.
● Car carrier trailers carry multiple cars, usually new cars from the manufacturer. In the US and elsewhere, car carriers often carry used vehicles as well. Similar variants can carry fork lift trucks, light commercial vehicles and agricultural tractors. Single-deck versions are used for larger vehicles.
● Conestoga trailers are a special form of flatbed trailer with a flexible retractable roof and siding used to carry large pieces of equipment that can only be lifted by an overhead crane, but which also need protection from the weather during transit.
● Curtain siders or Tautliners are similar to box trailers except the sides are movable curtains made of reinforced fabric coated with a waterproof coating. To put it another way, it is basically a flatbed trailer with additional aerodynamic and weather protection as well as greater load security. They generally have a restraining system of straps and buckles every foot (30cm) or so to keep the curtain tight and adverse to the elements. Also some have removable gates mounted into the trailer, to help reinforce the load and prevent bulges. The purpose of a curtain sider is to combine the security and weather resistance of a box trailer with the ease of loading of a flatbed. Curtain siders are one of the most common trailer types in Europe.
● Drop-deck trailers (or Step-frame Trailer) have a floor that drops down a level once clear of the tractor unit; the most common types of drop-deck trailers are flatbeds and curtain siders.
● Double deckers or deckers have either a fixed, hinged, or moveable second floor to enable them to carry more palletised goods. In general, a double decker can carry 40 pallets, as opposed to 26 for a standard trailer. Double deck trailers are generally a step-frame construction with the majority being either box or curtain siders, with box trailers having either a fixed or movable (floating) deck, and curtain sides having either a fixed or hinged second deck; this hinged second deck generally swings into a position down the length of the trailer, and can be divided into two or three sections to allow greater load flexibility. In Australia, they are known as mezzanine trailers or mezz-decks for short.
● Dry bulk ("British" Powder tankers) trailers resemble big tankers, but are used for cement, sand, barite, flour, and other dry powder materials.
● Dump trailers ("British" Tippers) are trailers in which one end can be raised to allow the cargo (often building materials or Agricultural produce) to slide out the other end. Commonly, they are hinged at the rear and raised at the front, but side-unloading dump trailers also are used.
● Flatbeds consist of just a load floor and removable side rails and a bulkhead in front to protect the tractor in the event of a load shift. They can haul almost anything that can be stacked on and strapped down.
● Hopper bottoms are usually used to haul grain, but can be used to haul other materials.
● Intermodal trailers are similar in frame design to box trailers, but without any sort of integral cargo-carrying ability as they are designed to carry a variety of standard Intermodal containers
● Live bottom trailers have a conveyor belt on the bottom of the trailer tub that pushes the load material out of the back of the trailer. The tub does not have to be raised to deposit the materials.
● Livestock trailers are used to haul livestock such as cattle, horses, pigs, sheep, etc. Commonly, they have two levels (or three for hogs) to maximize capacity.
● Lowboy ("British/Australian" Low-loader) trailers are a type of flatbed in which the load floor is as close to the ground as possible, most commonly used to haul heavy equipment, cranes, bulldozers, etc.
● Refrigerator trailers are box trailers with a heating/cooling unit (reefer) attached insulated walls, used for hauling produce, frozen foods, meat, flowers, etc. No quite as common but they are also produced in tautliner models with thicker curtains to sustain the fluctuating temperatures.
● Refrigerator tank trailers are well insulated or refrigerated to haul bulk liquid foods, such as liquid sugar, water, wine, milk or juices.
● Sidelifter semi-trailers have hydraulic cranes mounted at both ends of the chassis allowing for the loading and unloading of shipping containers without the need of a forklift or other container-handling equipment. Also known as a Sideloader.
● Tank chassis or "tanker" trailers are used for hauling liquids such as gasoline and alcohol, or various types of gases. They are similar in principle to intermodal trailers but with a very different frame intended to be attached to a liquid or gas tank, hence the name. Some are designed with a lowered centre of gravity to ensure greater stability. Generally bottom loaded with the ability to recover any waste vapor for safety reasons.
● A "frac" tank trailer has a single and fixed axle, and is typically used during hydraulic fracturing at oil wells or for petrochemical industries. It is shaped like a wedge, and when it is unhitched, its bottom side lies flat on the ground.
● "Wing" trailers are mostly found in Japan and are something of a hybrid between a curtain sider and a box trailer, with rigid, motorized Gull-wing doors in place of the fabric curtains. Also found as part of a rigid box truck.