In automobiles, a double wishbone (or "upper and lower A-arm") suspension is an independent suspension design using two (occasionally parallel) wishbone-shaped arms to locate the wheel. Each wishbone or arm has two mounting points to the chassis and one joint at the knuckle. The shock absorber and coil spring mount to the wishbones to control vertical movement. Double wishbone designs allow the engineer to carefully control the motion of the wheel throughout suspension travel, controlling such parameters as camber angle, caster angle, toe pattern, roll center height, scrub radius, scuff and more. This article or section does not cite its references or sources. ... The front suspension components of a Ford Model T. Suspension is the term given to the system of springs, shock absorbers and linkages that connects a vehicle to its wheels. ... Independent suspension is broad term for any automobile suspension system that allows each wheel on the same axle to move vertically (i. ... In automobiles, a control arm is a part of the suspension that connects the chassis or frame to the steering knuckles, which allows the body of the car to move relative to the wheel. ... Look up Chassis in Wiktionary, the free dictionary. ... Gasfilled Shock absorber. ... For other uses, see Spring. ... A wheel with a negative camber angle Camber angle is the angle made by the wheel of an automobile; specifically, it is the angle between the vertical axis of the wheel and the vertical axis of the vehicle when viewed from the front or rear. ... θ is the caster angle, red line is the pivot line, grey area is the tire Caster (or castor) angle is the angular displacement from the vertical axis of the suspension of a steered wheel in a car or other vehicle, measured in the longitudinal direction. ... Toe is the symmetric angle that each wheel makes with the longitudinal axis of the vehicle, as a function of static geometry, and kinematic and compliant effects. ... The roll center of a vehicle is the notional point at which the cornering forces in the suspension are reacted to the vehicle body. ... The scrub radius of a suspension is the distance between the steer axis of the suspension where it strikes the ground, and the centre of the contact patch, in front view. ...

Double Wishbone Suspension

The double wishbone suspension can also be referred to as double 'A' arms, and short long arm (SLA) suspension if the upper and lower arms are of unequal length. Download high resolution version (550x700, 64 KB)Left front wheel suspension of a Saab Quantum IV with double wishbones, showing kingpin axis, wheel hub, disc brake, steering arm and tire. ... Download high resolution version (550x700, 64 KB)Left front wheel suspension of a Saab Quantum IV with double wishbones, showing kingpin axis, wheel hub, disc brake, steering arm and tire. ...

SLAs are very common on front suspensions for medium to large cars such as the Honda Accord or Chrysler 300, pickups, SUVs, and are very common on sports cars and racing cars. The Honda Accord is an automobile manufactured by Honda since 1976, debuting as a compact hatchback and evolving into a intermediate vehicle. ...

A single wishbone or A-arm can also be used in various other suspension types, such as MacPherson strut and Chapman strut. This article or section does not cite its references or sources. ... A simple MacPherson strut suspension on the left front wheel of a rear-wheel drive vehicle. ... A Chapman strut is an automobile suspension device. ...

The suspension consists of a pair of upper and lower lateral arms. The upper arm is usually shorter to induce negative camber as the suspension jounces (rises). When the vehicle is in a turn, body roll results in positive camber gain on the outside wheel. The outside wheel also jounces and gains negative camber due to the shorter upper arm. The suspension designer attempts to balance these two effects to cancel out and keep the tire perpendicular to the ground. This is especially important for the outer tire because of the weight transfer to this tire during a turn.

Between the outboard end of the arms is a knuckle with a spindle (the kingpin), hub, or upright which carries the wheel bearing and wheel. Knuckles with an integral spindle usually do not allow the wheel to be driven. A bolt on hub design is commonly used if the wheel is to be driven. Ford Model T front suspension, showing the king pin. ... Bearing is the following: Often, bearing is the state of having something as a quality, characteristic, or permanent attribute. ...

In order to resist fore-aft loads such as acceleration and braking, the arms need two bushings or ball joints at the body. This article is about the vehicle component. ... This article or section does not adequately cite its references or sources. ...

At the knuckle end, single ball joints are typically used, in which case the steering loads have to be taken via a steering arm, and the wishbones look A- or L-shaped. An L-shaped arm is generally preferred on passenger vehicles because it allows a better compromise of handling and comfort to be tuned in. The bushing in line with the wheel can be kept relatively stiff to effectively handle cornering loads while the off-line joint can be softer to allow the wheel to recess under fore aft impact loads. For a rear suspension, a pair of joints can be used at both ends of the arm, making them more H-shaped in plan view.

In elevation view, the suspension is a 4-bar link, and it is easy to work out the camber gain (see camber angle) and other parameters for a given set of bushing or ball joint locations. A wheel with a negative camber angle Camber angle is the angle made by the wheel of an automobile; specifically, it is the angle between the vertical axis of the wheel and the vertical axis of the vehicle when viewed from the front or rear. ...

The various bushings or ball joints do not have to be on horizontal axes, parallel to the vehicle centre line. If they are set at an angle, then antidive and antisquat can be dialed in.

The advantage of a double wishbone suspension is that it is fairly easy to work out the effect of moving each joint, so you can tune the kinematics of the suspension easily and optimize wheel motion. It is also easy to work out the loads that different parts will be subjected to which allows more optimized lightweight parts to be designed. They also provide increasing negative camber gain all the way to full jounce travel unlike the MacPherson strut which provides negative camber gain only at the beginning of jounce travel and then reverses into positive camber gain at high jounce amounts. Kinematics (Greek κινειν,kinein, to move) is a branch of mechanics which describes the motion of objects without the consideration of the masses or forces that bring about the motion. ... A simple MacPherson strut suspension on the left front wheel of a rear-wheel drive vehicle. ...

The disadvantage is that it is slightly more complex than other systems like a MacPherson strut. A simple MacPherson strut suspension on the left front wheel of a rear-wheel drive vehicle. ...

Prior to the dominance of front wheel drive in the 1980s, many everyday cars used double wishbone front suspension systems, or a variation on it. Since that time, the MacPherson strut has become almost ubiquitous, as it is simpler and cheaper to manufacture. Double wishbones are usually considered to have superior dynamic characteristics, load handling capability and are still found on higher performance vehicles. Front wheel drive is the most common form of engine/transmission layout used in modern passenger cars, where the engine drives the front wheels. ... The 1980s refers to the years from 1980 to 1989. ... A simple MacPherson strut suspension on the left front wheel of a rear-wheel drive vehicle. ...

Robert (Bob) Sweat of MetalCraft Products, formerly in Romulus, Michigan, developed the Double Wishbone design as an independent contractor for Chrysler Automotive in the 1950's. Prior to this, only Ford had any that came close to independent.

List of vehicles with full Double Wishbone Suspension

Vehicles with both front/rear double wishbone suspension.

| all koenigseggs

See also

• Short Long Arms Suspension
• Strut bar
• Torsion beam suspension
• Dual ball joint suspension

An SLA is also known as an unequal length double wishbone suspension. ... Front Strut Bar mounted strut bar A strut bar or strut brace is a mostly aftermarket car suspension accessory used in conjunction with MacPherson struts on monocoque or unibody chassis to provide extra strength between the strut towers. ... Torsion beam suspension, also known as a torsion bar or torsion spring suspension, is a vehicle suspension system. ... A dual ball joint suspension uses a pair of arms, one in tension, one in compression, to replace a wishbone, in a MacPherson or SLA suspension. ...

External links

• AutoZine Technical School site