A trailing-arm suspension, also referred to as trailing-link, is a form of

vehicle suspension Suspension is the system of tires, tire air, spring (device), springs, shock absorbers and Linkage (mechanical), linkages that connects a vehicle to its wheels and allows relative motion between the two. Suspension systems must support b ...

. In a motor vehicle it places one or more horizontal arms (or "links") perpendicular to and forward of the

axle An axle or axletree is a central shaft for a rotation, rotating wheel and axle, wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In ...

on the

chassis A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of a manufactured object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart ...

unibody A vehicle frame, also historically known as its ''chassis'', is the main supporting structure of a motor vehicle to which all other components are attached, comparable to the skeleton of an organism. Until the 1930s, virtually every car had ...

, which are connected to the axle or wheels with pivot joint(s). These are typically used on the rear axle or wheels of vehicles, but also found in both front and main landing gear of aircraft. A "semi trailing-arm" (or semi trailing-link) is a common form of independent rear suspension on automobiles, particularly those with

front wheel drive Front-wheel drive (FWD) is a form of internal combustion engine, engine and transmission (mechanics), transmission layout used in motor vehicles, in which the engine drives the front wheels only. Most modern front-wheel-drive vehicles feature ...

(where it allows a flatter rear floor pan). Leading arms are similar horizontal arms, perpendicular to the axle, but connecting the wheels to the vehicle structure via pivot joints ''to the rear'' of them. These are typically used on the front axle or wheels, as on the

Citroën 2CV The Citroën 2CV (, , lit. "two horses", meaning "two Tax horsepower#France, ''taxable'' horsepower") is an economy car produced by the French company Citroën from 1948 to 1990. Introduced at the 1948 Paris Paris Auto Show, Salon de l'Automobi ...

and its derivatives, and on the

Citroën DS The Citroën DS () is a Front-mid-engine, front-wheel-drive layout, front mid-engined, front-wheel drive executive car manufactured and marketed by Citroën from 1955 to 1975, in fastback/sedan, wagon/estate, and convertible body configurations ...

, as well as on the M422 Mighty Mite jeep.

Types

Trailing-arm

Trailing-arm designs in

live axle A beam axle, rigid axle, or solid axle is a dependent suspension design in which a set of wheels is connected laterally by a single beam or shaft. Beam axles were once commonly used at the rear wheels of a vehicle, but historically, they have a ...

setups often use just two or three links and a

Panhard rod A Panhard rod (also called Panhard bar, track bar, or track rod) is a suspension link that provides lateral location of the axle. Invented by the Panhard automobile company of France in the early twentieth century, this device has been widely use ...

to locate the wheel laterally. A trailing arm design can also be used in an

independent suspension Independent suspension is any automobile suspension system that allows each wheel on the same axle to move vertically (i.e. reacting to a bump on the road) independently of the others. This is contrasted with a beam axle or deDion axle system in ...

arrangement. Each

wheel A wheel is a rotating component (typically circular in shape) that is intended to turn on an axle Bearing (mechanical), bearing. The wheel is one of the key components of the wheel and axle which is one of the Simple machine, six simple machin ...

hub is located only by a large, roughly triangular arm that pivots at one point, ahead of the wheel. Seen from the side, this arm is roughly parallel to the ground, with the angle changing based on road irregularities. A

twist-beam rear suspension The twist-beam rear suspension (also torsion-beam axle, deformable torsion beam, or compound crank) is a type of automobile suspension (vehicle), suspension based on a large H- or C-shaped member. The front of the H attaches to the body via rub ...

is very similar except that the arms are connected by a beam, used to locate the wheels and which twists and has an anti-roll effect. Some aircraft also use trailing arms in their

landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for taxiing, takeoff or landing. For aircraft, it is generally needed for all three of these. It was also formerly called ''alighting gear'' by some manufacturers, s ...

, with

oleo strut An oleo strut is a pneumatic air–oil hydraulic shock absorber used on the landing gear of most large aircraft and many smaller ones. This design cushions the impacts of landing and damps out vertical oscillations. It is undesirable for an air ...

s for shock absorption. A trailing arm landing gear results in smoother landings and a better ride when

taxiing Taxiing (rarely spelled taxying) is the movement of an aircraft on the ground, under its own power, in contrast to towing or pushback (aviation), pushback where the aircraft is moved by a tug. The aircraft usually moves on wheels, but the term ...

compared to other types of landing gear.

Semi-trailing arm

A semi-trailing arm suspension is a supple independent rear suspension system for

automobile A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, peopl ...

s where each

hub is located only by a large, roughly triangular arm that pivots at two points. Viewed from the top, the line formed by the two pivots is somewhere between parallel and

perpendicular In geometry, two geometric objects are perpendicular if they intersect at right angles, i.e. at an angle of 90 degrees or π/2 radians. The condition of perpendicularity may be represented graphically using the '' perpendicular symbol'', � ...

to the car's longitudinal axis; it is generally parallel to the ground. Trailing-arm and multilink suspension designs are much more commonly used for the rear wheels of a vehicle where they can allow for a flatter floor and more cargo room. Many small,

front-wheel drive Front-wheel drive (FWD) is a form of internal combustion engine, engine and transmission (mechanics), transmission layout used in motor vehicles, in which the engine drives the front wheels only. Most modern front-wheel-drive vehicles feature ...

vehicles feature a

MacPherson strut The MacPherson strut is a type of automotive suspension system that uses the top of a telescopic damper as the upper steering pivot. It is widely used in the front suspension of modern vehicles. The name comes from American automotive engineer ...

front suspension and trailing-arm rear axle.

References

{{DEFAULTSORT:Trailing Arm Automotive suspension technologies Aircraft components

Types

Trailing-arm

Semi-trailing arm

See also

References