A (semi) trailing-arm suspension, sometimes referred to as (semi) trailing-link is a vehicle axle or wheel suspension design in which one or more horizontal arms (or "links"),

perpendicular In elementary geometry, two geometric objects are perpendicular if they intersect at a right angle (90 degrees or π/2 radians). The condition of perpendicularity may be represented graphically using the ''perpendicular symbol'', ⟂. It can ...

to and forward of the

axle An axle or axletree is a central shaft for a rotating 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 the former case, beari ...

, are connecting the axle or wheels with pivot joint(s) ahead of them, on the structure (

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 ...

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

) of a motor vehicle. These are typically used on the rear axle or wheels of a vehicle, but also found in aircraft landing gear. 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 (french: link=no, deux chevaux(-vapeur), , lit. "two steam horse(power)s", meaning "two ''taxable'' horsepower") is an air-cooled front-engine, front-wheel-drive, economy family car, introduced at the 1948 Paris Mondial d ...

and its derivatives, and on the

Citroën DS The Citroën DS () is a 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, across three series of one generation. M ...

, 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 als ...

setups often use just two or three links and a Panhard rod 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 i ...

arrangement. Each

wheel A wheel is a circular component that is intended to rotate on an axle bearing. The wheel is one of the key components of the wheel and axle which is one of the six simple machines. Wheels, in conjunction with axles, allow heavy objects to be ...

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 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 takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Marti ...

, 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 where the aircraft is moved by a tug. The aircraft usually moves on wheels, but the term also includes aircr ...

compared to other types of landing gear.

Semi-trailing arm

A semi-trailing arm suspension is a supple

independent rear 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 ...

system for

automobile A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded ...

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

to the car's longitudinal axis; it is generally parallel to the ground. Trailing-arm and

multilink suspension A multi-link suspension is a type of vehicle suspension with one or more longitudinal arms. A wider definition can consider any independent suspensions having three control links or more multi-link suspensions. These arms do not have to be of eq ...

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 engine and transmission layout used in motor vehicles, where the engine drives the front wheels only. Most modern front-wheel drive vehicles feature a transverse engine, rather than the conventional longi ...

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, and is named for American automotive engineer Earl ...

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