To meet Wikipedia's quality standards, capitalizations in this article need to be corrected: All proper names should be capitalized in the body of the text Use standard capitalization rules for trademarks (even if the trademark owner encourages special treatment). Never use all caps, and album/song names should be in title case, (Let It Be)

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. Suspension systems serve a dual purpose – contributing to the car's handling and braking for good active safety and driving pleasure, and keeping vehicle occupants comfortable and reasonably well isolated from road noise, bumps, and vibrations. These goals are generally at odds, so the tuning of suspensions involves finding the right compromise. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different. Image File history File links Acap. ... Capitalization (or capitalisation) is writing a word with its first letter as a majuscule (upper case letter) and the remaining letters in minuscules (lower case letters), in those writing systems which have a case distinction. ... Image File history File links Download high resolution version (2272x1704, 514 KB) The suspension components of a Ford Model T. The coil spring device is an aftermarket accessory shock absorber. ... Image File history File links Download high resolution version (2272x1704, 514 KB) The suspension components of a Ford Model T. The coil spring device is an aftermarket accessory shock absorber. ... For the blues musician, see T-Model Ford. ... Helical or coil springs designed for tension A spring is a flexible elastic object used to store mechanical energy. ... Gasfilled Shock absorber. ... The locking pliers is an example of a four-bar, one degree of freedom mechanical linkage; or a five-bar, two DOF linkage when the adjustment screw is considered. ... The Trikke is a Human Powered Vehicle (HPV) Automobiles are among the most commonly used engine powered vehicles. ... For other uses, see Wheel (disambiguation). ... Car handling and vehicle handling is a description of the way wheeled vehicles perform transverse to their direction of motion, particularly during cornering and swerving. ... This article needs additional references or sources for verification. ... Although front-wheel drive cars usually have one of a few varieties of independent rear suspensions, it is the greater variety and the reasons for each particular design which concern this article, which concerns rear-wheel drive cars. ...

This article is primarily about four-wheeled (or more) vehicle suspension. For information on two-wheeled vehicles' suspensions see the suspension (motorcycle), motorcycle fork, bicycle suspension, and bicycle fork articles. A motorcycles suspension is similar to the suspension in an automobile in its purpose: But a motorcycle suspension is usually simpler, since it does not have to contend with lateral forces such as body roll. ... 1968 BMW R60US with conventional telescopic fork Yamahas inverted telescopic fork The worlds first oil-damped telescopic fork, on a 1939 BMW R12 Trailing link fork on a 1928 BMW R57 Unusual trailing bottom link on a Honda Rune Earles front forks on three BMWs BMW Telelever fork... A full suspension Mountain Bike // Bicycle suspension refers to the system or systems used to suspend the rider and all or part of the bicycle in order to protect them from the roughness of the terrain over which they travel. ... bicycle fork A bicycle fork is the portion of a bicycle that holds the front wheel and allows one to steer. ...

History

Please help improve this article or section by expanding it. Further information might be found on the talk page or at requests for expansion. (May 2007)

Leaf springs have been around since the Early Egyptians. Image File history File links This is a lossless scalable vector image. ... A leaf spring is a simple form of spring, commonly used for the suspension in wheeled vehicles. ...

Ancient military engineers used leaf springs in the form of bows to power their siege engines, with little success at first. The use of leaf springs in catapults was later refined and made to work years later. Springs were not only made of metal, a sturdy tree branch could be used as a spring, such as with a bow.

Early suspension devices were developed for stagecoaches in early modern Britain. The physical laws of damping were not discovered until the 19th century^{[citation needed]}. Stagecoach in Switzerland A stagecoach is a type of four-wheeled enclosed passenger and/or mail coach, strongly sprung and drawn by four horses, widely used before the introduction of railway transport. ... Early Modern Britain is a term used to define the period in the history of Great Britain roughly corresponding to the 16th, 17th, and 18th centuries. ... Damping is any effect, either deliberately engendered or inherent to a system, that tends to reduce the amplitude of oscillations of an oscillatory system. ...

Important properties

Spring rate

Further information: Spring rate

Spring rate (or suspension rate) is a component in setting the vehicle's ride height or its location in the suspension stroke. Vehicles which carry heavy loads will often have heavier than desired springs to compensate for the additional weight that would otherwise collapse a vehicle to the bottom of its travel (stroke). Heavier springs are also used in performance applications when the suspension is constantly forced to the bottom of its stroke causing a reduction in the useful amount of suspension travel which may also lead to harsh bottoming. The rate of a spring is the change in the force it exerts, divided by the change in deflection of the spring. ...

Springs that are too hard or too soft will both effectively cause the vehicle to have no suspension at all. Vehicles that commonly experience suspension loads heavier than normal have heavy or hard springs with a spring rate close to the upper limit for that vehicle's weight. This allows the vehicle to perform properly under a heavy load when control is limited by the inertia of the load. Riding in an empty truck used for carrying loads can be uncomfortable for passengers because of its high spring rate relative to the weight of the vehicle. A race car would also be described as having heavy springs and would also be uncomfortably bumpy. However, even though we say they both have heavy springs, the actual spring rates for a 2000 lb race car and a 10,000 lb truck are very different. A luxury car, taxi, or passenger bus would be described as having soft springs. Vehicles with worn out or damaged springs ride lower to the ground which reduces the overall amount of compression available to the suspension and increases the amount of body lean. Performance vehicles can sometimes have spring rate requirements other than vehicle weight and load. This article is about inertia as it applies to local motion. ...

Mathematics of the spring rate

Spring rate is a ratio used to measure how resistant a spring is to being compressed or expanded during the spring's deflection. The magnitude of the spring force increases as deflection increases according to Hooke's Law. Briefly, this can be stated as A ratio is a quantity that denotes the proportional amount or magnitude of one quantity relative to another. ... This article or section does not cite any references or sources. ... Hookes law accurately models the physical properties of common mechanical springs for small changes in length. ...

F = − kx

where F is the spring force, k the spring constant, and x the displacement. Spring rate is confined to a narrow interval by the weight of the vehicle, the load the vehicle will carry, and to a lesser extent by suspension geometry and performance desires.

Spring rates typically have units of N/mm (or lbf/in). An example of a linear spring rate is 500 lbf/in. For every inch the spring is compressed, it exerts 500 lbf. A non-linear spring rate is one for which the relation between the spring's compression and the force exerted cannot be fitted adequately to a linear model. For example, the first inch exerts 500 lbf force, the second inch exerts an additional 550 lbf (for a total of 1050 lbf), the third inch exerts another 600 lbf (for a total of 1650 lbf). In contrast a 500 lbf/in linear spring compressed to 3 inches will only exert 1500 lbf. For other uses, see Newton (disambiguation). ... A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ... The pound-force is a non-SI unit of force or weight (properly abbreviated lbf or lbf). The pound-force is equal to a mass of one pound multiplied by the standard acceleration due to gravity on Earth (which is defined as exactly 9. ... An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ...

The spring rate of a coil spring may be calculated by a simple algebraic equation or it may be measured in a spring testing machine. The spring constant k can be calculated as follows:

where d is the wire diameter, E is the spring's elastic modulus (e.g., about 12,000,000 lbf/in² or 83 GPa for steel), and N is the number of wraps and D is the diameter of the coil. An elastic modulus, or modulus of elasticity, is the mathematical description of an object or substances tendency to be deformed when a force is applied to it. ... A pressure gauge reading in PSI (red scale) and kPa (black scale) The pound-force per square inch (symbol: lbf/in2) is a non-SI unit of pressure based on avoirdupois units. ... The initials GPA can refer, among other things, to Grade Point Average; see Grade (education) Guinness Peat Aviation General Practice Australia, a private, independent medical accreditation society Greyhound Pets of America This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same...

Wheel rate

Wheel rate is the effective spring rate when measured at the wheel. This is as opposed to simply measuring the spring rate alone.

Wheel rate is usually equal to or considerably less than the spring rate. Commonly, springs are mounted on control arms, swing arms or some other pivoting suspension member. Consider the example above where the spring rate was calculated to be 500lbs/inch, if you were to move the wheel 1 inch (without moving the car), the spring more than likely compresses a smaller amount. Lets assume the spring moved 0.75 inches, the lever arm ratio would be 0.75 to 1. The wheel rate is calculated by taking the square of the ratio (0.5625) times the spring rate. Squaring the ratio is because the ratio has two effects on the wheel rate. The ratio applies to both the force and distance traveled.

Wheel rate on independent suspension is fairly straight-forward. However, special consideration must be taken with some non-independent suspension designs. Take the case of the straight axle. When viewed from the front or rear, the wheel rate can be measured by the means above. Yet because the wheels are not independent, when viewed from the side under acceleration or braking the pivot point is at infinity (because both wheels have moved) and the spring is directly inline with the wheel contact patch. The result is often that the effective wheel rate under cornering is different than it is under acceleration and braking. This varying wheel rate can be minimized by locating the spring as close to the wheel as possible without damaging the tire during cornering. Race cars (like NASCAR) often have rear leaf springs showing signs of contact with the tire. The paint has been polished off but no damage to the tire has occurred.(Note: NASCAR legal race cars have coil springs on all four corners)

Roll couple percentage

Roll couple percentage is the effective wheel rates, in roll, of each axle of the vehicle as a ratio of the vehicle's total roll rate. Roll Couple Percentage is critical in accurately balancing the handling of a vehicle.

A vehicle with a roll couple percentage of 70% will transfer 70% of its sprung weight transfer at the front of the vehicle during cornering.

Wheel rates used in roll couple calculations must include anti-roll bar wheel rates. Many "very knowledgable, well paid" engineers have made the error of calculating the anti-roll bar's spring rate incorrectly for use in roll couple calculations. "Bump" wheel rate of the anti-roll bar is calculated by moving 1 wheel 1 inch with the other end fixed. But, roll couple is different.

Total front wheel rates are measured by deflecting both wheels 1 inch in opposite directions giving you a 2 inch movement on the Anti-Roll Bar. The Anti-Roll Bar Wheel Rate should be calculated by using only half the length of the bar, not the entire length. The same would be true of a Rear Anti-Roll Bar. (Endless NASCAR, Indy, Formula-1 etc. teams set up their cars in the shop and take them to the track and wonder why they have a noticeable Understeer. Many teams only discover the error after installing data acquisition systems that include monitoring Anti-Roll Bar loads. Most only monitor force loads and deflection on the actual springs but not the forces on the Anti-Roll Bar.) ^{[citation needed]}

Weight transfer

Weight transfer during cornering, acceleration or braking is usually calculated per individual wheel and compared with the static weights for the same wheels. Cornering wheel weights requires knowing the static wheel weights and adding or subtracting the unsprung, sprung and jacking forces at each wheel. Some auto racing circles use false terms, or combine things like jacking forces and sprung weight transfer and call it by terms like "side bite". They are either unknowing by ignorance or intentionally confusing competitors by not dealing with vehicle fundamentals and using commonly accepted anthropomorphic terms. Anthropomorphism, also referred to as personification or prosopopeia, is the attribution of human characteristics to inanimate objects, animals, forces of nature, and others. ...

Unsprung weight transfer

Unsprung Weight Transfer is calculated based on the weight of the vehicles components that are not supported by the springs. This includes tires, wheels, brakes, spindles, half the control arm's weight and other components. These components are then (for calculation purposes) assumed to be connected to a vehicle with zero sprung weight. They are then put through the same dynamic loads. The weight transfer for cornering in the front would be equal to the total unsprung front weight times the G-Force times the front unsprung center of gravity height divided by the front track width. Likewise for the rear.

Sprung weight transfer

Sprung Weight Transfer is the weight transferred by only the weight of the vehicle resting on the springs not the total vehicle weight. Calculating this requires knowing the vehicles sprung weight (total weight less the unsprung weight), the front and rear roll center heights and the sprung center of gravity height (used to calculate the roll moment arm length). Calculating the front and rear sprung weight transfer will also require knowing the roll couple percentage. In a vehicle with a suspension, such as an automobile or a tank, sprung mass (or sprung weight) is the portion of the vehicles total mass that is supported by the suspension. ...

The roll axis is the line through the front and rear roll centers that the vehicle rolls around during cornering. The distance from this axis to the sprung center of gravity height is the roll moment arm length. The total sprung weight transfer is equal to the G-force times the sprung weight times the roll moment arm length divided by the effective track width. The front sprung weight transfer is calculated by multiplying the roll couple percentage times the total sprung weight transfer. The rear is just the total minus the front transfer. The term g force or gee force refers to the symbol g, the force of acceleration due to gravity at the earths surface. ...

Jacking forces

Jacking forces can be thought of as the centripetal force pushing diagonally upward from the tire contact patch into the suspension roll center. The front jacking force is calculated by taking the front sprung weight times the G-force times the front roll center height divided by the front track width. The rear is calculated the same way except at the rear.

Travel

Travel is the measure of distance from the bottom of the suspension stroke (such as when the vehicle is on a jack and the wheel hangs freely), to the top of the suspension stroke (such as when the vehicles wheel can no longer travel in an upward direction toward the vehicle). Bottoming or lifting a wheel can cause serious control problems or directly cause damage. "Bottoming" can be either the suspension, tires, fenders, etc. running out of space to move or the body or other components of the car hitting the road. The control problems caused by lifting a wheel are less severe if the wheel lifts when the spring reaches its unloaded shape than they are if travel is limited by contact of suspension members. (See Triumph TR3B.) Triumph TR2 The Triumph TR3B was produced by the Triumph Motor Company (Standard Motor Company) in 1962. ...

Damping

Damping (not to be confused with dampening) is the control of motion or oscillation, as seen with the use of hydraulic gates and valves in a vehicles shock absorber. This may also vary, intentionally or unintentionally. Like spring rate, the optimal damping for comfort may be less than for control. Damping is any effect, either deliberately engendered or inherent to a system, that tends to reduce oscillations. ...

Damping controls the travel speed and resistance of the vehicles suspension. An undamped car will oscillate up and down. With proper damping levels, the car will settle back to a normal state in a minimal amount of time. Most damping in modern vehicles can be controlled by increasing or decreasing the resistance to fluid flow in the shock absorber.

Camber control

See dependent and independent below.

Camber changes with wheel travel and with body roll. A tire wears and brakes best perpendicular to the road. Depending on the tire, it may hold the road best at a slightly different angle. Small changes in camber, front and rear, are used to tune handling. 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. ... This article needs additional references or sources for verification. ...

Roll center height

This is important to body roll and to front to rear roll moment distribution. However, the roll moment distribution in most cars is set more by the antiroll bars than the RCH. It may affect the tendency to roll over. A sway bar (also stabilizer bar, anti-sway bar, roll bar, or anti-roll bar, ARB) is an automobile suspension device. ...

Instant center

A tire's force vector points from the contact patch of the tire through a point referred to as the "instant center". This imaginary point is the effective geometric point at which the suspension force vectors are transmitted to the chassis. Another way of looking at this is to imagine each suspension control arm mounted only at the frame. The axis that the arm rotates around creates an imaginary line running through the vehicle. Forces, as far as suspension geomentry are concerned, are transmitted either along this axis (usually front to rear) or through this axis at a right angle (usually right to left and intersects the ball joint). When you intersect the force lines of the upper and lower control arms, where they cross is the Instant Center. The Instant Centers when viewed from the front or side may not seem to have much of a relation to each other until you imagine the points in three dimensions. Sometimes the Instant Center is at ground level or at a distant point due to parallel control arms.

The instant center can also be thought of as having the effect of converting multilink suspension into a single control arm which pivots at the Instant Center. This is only true at a given suspension deflection, because an unequal length, multi-link system has an instant center that moves as the suspension is deflected.

Anti-dive and anti-squat

Anti-dive and anti-squat are expressed in terms of percentage and refer to the front diving under braking and the rear squating under acceleration. They can be thought of as the counterparts for braking and acceleration as roll center height is to cornering. The main reason for the difference is due to the different design goals between front and rear suspension, whereas suspension is usually symmetrical between the left and right of the vehicle.

Anti-dive and anti-squat percentage are always calculated with respect to a vertical plane that intersects the vehicle's Center of Gravity. Consider Anti-dive first. Locate the front Instant Centers of the suspension from the vehicle's side view. Draw a line fron the tire contact patch through the Instant Center, this is the tire force vector. Now draw a line straight down from the vehicle's center of gravity. The Anti-dive is the ratio between the height of where the tire force vector crosses the center of gravity plane expressed as a percentage. An Anti-dive ratio of 50% would mean the force vector under braking crosses half way between the ground and the center of gravity.

Anti-squat is the counterpart to Anti-dive and is for the rear suspension under acceleration.

Anti-dive and anti-squat may or may not be desirable depending on the suspension design. Independent suspension using multiple control arms can be an issue if the percentage is too high (say over 30%). A percentage of 100% in this case would indicate the suspension is taking 100% of the weight transfer under braking instead of the springs. This effectively binds the suspension and turns the independent suspension into no suspension like a go-cart. However, in the case of leaf spring rear suspension the Anti-squat can often exceed 100% (meaning the rear may actually raise under acceleration) yet because there isn't a second arm to bind against and the suspension can freely move. Traction bars are often added to drag racing cars with leaf spring rear to increase the Anti-squat to its maximum. This has the effect of forcing the rear of the car in the air and the tires onto the ground for better traction.

Flexibility and vibration modes of the suspension elements

In modern cars, the flexibility is mainly in the rubber bushings.

Isolation from high frequency shock

For most purposes, the weight of the suspension components is unimportant, but at high frequencies, caused by road surface roughness, the parts isolated by rubber bushings act as a multistage filter to suppress noise and vibration better than can be done with only the tires and springs. (The springs work mainly in the vertical direction.)

Contribution to unsprung weight and total weight

These are usually small, except that the suspension is related to whether the brakes and differential(s) are sprung.

Space occupied

Designs differ as to how much space they take up and where it is located. It is generally accepted that MacPherson struts are the most compact arrangement for front-engined vehicles, where space between the wheels is required to place the engine. A simple MacPherson strut suspension on the left front wheel of a rear-wheel drive vehicle. ...

Force distribution

The suspension attachment must match the frame design in geometry, strength and rigidity.

Air resistance (drag)

Certain modern vehicles have height adjustable suspension in order to improve aerodynamics and fuel efficiency. Height adjustable suspension is a feature of certain automobile suspension (vehicle) systems that allow the motorist to vary the ride height or ground clearance. ...

Cost

Production methods improve, but cost is always a factor. The continued use of the solid rear axle, with unsprung differential, especially on heavy vehicles, seems to be the most obvious example.

Springs and dampers

Most suspensions use springs to absorb impacts and dampers (or shock absorbers) to control spring motions. Some notable exceptions are the hydropneumatic systems, which can be treated as an integrated unit of gas spring and damping components, used by the French manufacturer Citroën and the hydrolastic, hydragas and rubber cone systems used by the British Motor Corporation, most notably on the Mini. A number of different types of each have been used: Helical or coil springs designed for tension A spring is a flexible elastic object used to store mechanical energy. ... Gasfilled Shock absorber. ... Hydropneumatic is the name given to a suspension system invented by Citroën and fitted to Citroën cars, as well as being adapted by other car manufacturers, notably Rolls-Royce, Mercedes-Benz and Peugeot. ... Citroën is a French automobile manufacturer, founded in 1919 by André Citroën. ... Hydrolastic is a type of automotive suspension system used in many cars produced by British Motor Corporation (BMC) and its successor companies. ... Hydragas is a type of automotive suspension system used in many cars produced by British Leyland and its successor companies. ... BMC rosette logo old BMC share A preserved BMC ambulance. ... For the new MINI, see MINI (BMW). ...

Conventional passive, semi-active/active, and interconnected suspensions

Traditional springs and dampers are referred to as passive suspensions. If the suspension is externally controlled then it is a semi-active or active suspension.

Semi-active suspensions include devices such as air springs and switchable shock absorbers, various self-levelling solutions, as well as systems like Hydropneumatic, Hydrolastic, and Hydragas suspensions. Delphi currently sells shock absorbers filled with a magneto-rheological fluid, whose viscosity can be changed electromagnetically, thereby giving variable control without switching valves, which is faster and thus more effective. Self-levelling refers to an automobile suspension system that maintains a constant ride height of the vehicle above the road, regardless of load. ... Hydropneumatic is the name given to a suspension system invented by Citroën and fitted to Citroën cars, as well as being adapted by other car manufacturers, notably Rolls-Royce, Mercedes-Benz and Peugeot. ... Hydrolastic is a type of automotive suspension system used in many cars produced by British Motor Corporation (BMC) and its successor companies. ... Hydragas is a type of automotive suspension system used in many cars produced by British Leyland and its successor companies. ... A magnetorheological fluid is a type of smart fluid. ...

For example, a hydropneumatic Citroën will "know" how far off the ground the car is supposed to be and constantly reset to achieve that level, regardless of load. It will not instantly compensate for body roll due to cornering however. Citroën's system adds about 1% to the cost of the car versus passive steel springs.

Fully active suspensions use electronic monitoring of vehicle conditions, coupled with the means to impact vehicle suspension and behavior in real time to directly control the motion of the car. Lotus Cars developed several prototypes, and introduced them to F1, where they have been fairly effective, but have now been banned. Nissan introduced a low bandwidth active suspension in circa 1990 as an option that added an extra 20% to the price of luxury models. Citroën has also developed several active suspension models (see hydractive). A recently publicised fully active system from Bose Corporation uses linear electric motors, ie solenoids, in place of hydraulic or pneumatic actuators that have generally been used up until recently. The most advanced suspension system is Active Body Control, introduced in 1999 on the top-of-the-line Mercedes-Benz CL-Class. Lotus Logo with monogram of its founder, Anthony Colin Bruce Chapman Lotus Cars is a British manufacturer of sports and racing cars based at Hethel, Norfolk, England. ... Nissan Motor Co. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... The Bose Corporation is a privately-held American company based in Framingham, Massachusetts that specializes in audio equipment[2][3] and holds the philosophy of supporting its technological development through research (thus the company motto). ... Mercedes-Benz S Class Mercedes-Benz CL Class Mercedes-Benz SL Class Active Body Control, or ABC, is the Mercedes-Benz brand name used to describe fully-active suspension, that allows control of the vehicle body motions and therefore virtually eliminates body roll in many driving situations including cornering, accelerating... 1993 Mercedes-Benz 600 SEC, a predecessor of the modern CL-Class 2005 Mercedes-Benz CL65 AMG 2001 Mercedes-Benz CL63 AMG The Mercedes-Benz CL-Class is a grand tourer produced by the German automaker Mercedes-Benz. ...

With the help of control system, various semi-active/active suspensions could realize an improved design compromise among different vibrations modes of the vehicle, namely bounce, roll, pitch and warp modes. However, the applications of these advanced suspensions are constrained by the cost, packaging, weight, reliability, and/or the other challenges.

Interconnected suspension, unlike semi-active/active suspensions, could easily decouple different vehicle vibration modes in a passive manner. The interconnections can be realized by various means, such as mechanical, hydraulic and pneumatic. Anti-roll bars are one of the typical examples of mechanical interconnections, while it has been stated that fluidic interconnections offer greater potential and flexibility in improving both the stiffness and damping properties. Considering the considerable commercial potentials of hydropneumatic technology (Crolla, 1996), interconnected hydropneumatic suspenisons have also been explored in some recent studies, and their potnetial benefits in enhancing vehicle ride and handling have been demonstrated. The control system can also be used for further improving performance of interconnected suspensions. Apart from academic research, an Australian company, Kinetic, is having some success (WRC: 3 Championships, Dakar Rally: 2 Championships, Lexus GX470 2004 4x4 of the year with KDSS, 2005 PACE award) with various passive or semi-active systems, which generally decouple at least two vehicle modes (roll, warp (articulation), pitch and/or heave (bounce)) to simultaneous control each mode’s stiffness and damping, by using interconnected shock absorbers, and other methods. In 1999 Kinetic was bought out by Tenneco. WRC is a three-letter abbreviation with multiple meanings, as described below: World Rally Championship, a series of automobile rally races and World Rally Car, the class of cars involved in them Will Rice College, a residential college of Rice University Western Reserve College, a prep school in Hudson, Ohio... For information about the 2007 Dakar Rally, see 2007 Dakar Rally. ...

Historically, the first mass production car with front to rear mechanical interconnected suspension was the 1948 Citroen 2cv. The suspension of the 2CV was extremely soft — it had low roll stiffness, but its pitch stiffness was increased by using an interconnected suspension. The leading arm / trailing arm swinging arm, fore-aft linked suspension system together with inboard front brakes had a much smaller unsprung weight than existing coil spring or leaf designs. The interconnection transmitted some of the force deflecting a front wheel up over a bump, to push the rear wheel down on the same side. When the rear wheel met that bump a moment later, it did the same in reverse, keeping the car level front to rear. The 2CV had a design brief to be able to be driven at speed over a ploughed field. It originally featured friction dampers and tuned mass dampers. Later models had tuned mass dampers at the front with telescopic dampers / shock absorbers front and rear. 1960 2CV. Notice suicide doors The 2CV (deux chevaux - French, literally two horses, from the tax power rating) was a popular French car made by Citroën. ... A trailing-arm suspension is an automobile suspension design in which one or more arms (or links) are connected between (and perpendicular to) the axle and the chassis. ... This does not cite its references or sources. ... This article does not cite any references or sources. ... This article does not cite any references or sources. ... Gasfilled Shock absorber. ...

Some of the last post war Packard models also featured interconnected suspension. The original Mini and some more recent British Leyland models also featured interlinking, when fitted with Moulton's Hydrolastic or Hydragas suspensions^[1]. The Packard family coat of arms, adopted as the companys logo in 1928 Packard red hexagon wheel hub center made its debut in 1905, with the color red added in 1913 Packard was a United States based brand of luxury automobile built by the Packard Motor Car Company of...

Springs

• Leaf spring - AKA Hotchkiss, Cart, or semi-elliptical spring
• Torsion beam suspension
• Coil spring
• Rubber bushing
• Air spring

A traditional leaf spring arrangement. ... Torsion beam suspension, also known as a torsion bar or torsion spring suspension, is a vehicle suspension system. ... A compression coil spring A tension coil spring A selection of conical coil springs A Coil spring, also known as a helical spring, is a mechanical device, which is typically used to store energy and subsequently release it, to absorb shock, or to maintain a force between contacting surfaces. ... This does not cite any references or sources. ... This article or section does not adequately cite its references or sources. ...

Dampers or shock absorbers

The shock absorbers damp out the (otherwise resonant) motions of a vehicle up and down on its springs. They also must damp out much of the wheel bounce when the unsprung weight of a wheel, hub, axle and sometimes brakes and differential bounces up and down on the springiness of a tire. The regular bumps found on dirt roads (nicknamed "corduroy", but properly washboarding) are caused by this wheel bounce. These bumps are more common on US dirt roads, where solid rear axles are common, than they are in e.g. French dirt roads, where unsprung weight tends to be low and suspensions well damped. This does not cite its references or sources. ... In an automobile and other four-wheeled vehicles, a differential is a device, usually consisting of gears, for allowing each of the driving wheels to rotate at different speeds, while supplying equal torque to each of them. ... This article does not cite its references or sources. ... Washboarding is a process which results in roads (particularly gravel roads or dirt roads) developing a series of regular bumps with short spacing in the road surface. ...

Suspension types

Suspension systems can be broadly classified into two subgroups - dependent and independent. These terms refer to the ability of opposite wheels to move independently of each other.

A dependent suspension normally has a live axle (a simple beam or 'cart' axle) that holds wheels parallel to each other and perpendicular to the axle. When the camber of one wheel changes, the camber of the opposite wheel changes in the same way (by convention on one side this is a positive change in camber and on the other side this a negative change). A live axle is a type of beam axle suspension system that uses the driveshafts that transmit power to the wheels to connect the wheels laterally so that they move together as a unit. ... 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. ...

An independent suspension allows wheels to rise and fall on their own without affecting the opposite wheel. Suspensions with other devices, such as anti-roll bars that link the wheels in some way are still classed as independent. Independent suspension is broad term for any automobile suspension system that allows each wheel on the same axle to move vertically (i. ... A sway bar (also called an anti-sway bar or anti-roll bar) is an automobile suspension device. ...

A third type is a semi-dependent suspension. In this case, jointed axles are used, on drive wheels, but the wheels are connected with a solid member, most often a deDion axle. This differs from "dependent" mainly in unsprung weight. A de Dion tube is an automobile suspension technology. ...

Dependent suspensions

Dependent systems may be differentiated by the system of linkages used to locate them, both longitudinally and transversely. Often both functions are combined in a set of linkages.

Examples of location linkages include:

• Trailing arms
• Satchell link
• Panhard rod
• Watt's linkage
• WOBLink
• Mumford linkage
• leaf springs used for location (transverse or longitudinal)
  • Fully elliptical springs usually need supplementary location links and are no longer in common use
  • Longitudinal semi-elliptical springs used to be common and still are used on some US cars and on trucks. They have the advantage that the spring rate can easily be made progressive (non-linear)
  • A single transverse leaf spring for both front wheels and/or both back wheels, supporting solid axles was used by Ford Motor Company, before and soon after World War II, even on expensive models. It had the advantages of simplicity and low unsprung weight (compared to other solid axle designs), as well as the other advantages of solid axles.

In a front engine rear drive vehicle, dependent rear suspension is either "live axle" or deDion axle, depending on whether or not the differential is carried on the axle. Live axle is simpler but the unsprung weight contributes to wheel bounce. A trailing-arm suspension is an automobile suspension design in which one or more arms (or links) are connected between (and perpendicular to) the axle and the chassis. ... A Panhard rod is a component of a car suspension system that provides lateral location of the axle. ... Watts Linkage The Watts linkage was invented by James Watt (1736--1819) to constrain the movement of a piston in a steam engine to move in a straight line. ... A traditional leaf spring arrangement. ... “Ford” redirects here. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... A de Dion tube is an automobile suspension technology. ...

Because it assures constant camber, dependent (and semi-independent) suspension is most common on vehicles that need to cary large loads, as a proportion of the vehicle weight, that have relatively soft springs and that do not (for cost and simplicity reasons) use active suspensions. However the use of dependent front suspension has become limited to a few trucks.

Independent suspensions

Main article: Independent suspension

The variety of independent systems is greater and includes: Independent suspension is broad term for any automobile suspension system that allows each wheel on the same axle to move vertically (i. ...

• Swing axle
• Sliding pillar
• MacPherson strut/Chapman strut
• Upper and lower A-arm (double wishbone)
• multi-link suspension
• semi-trailing arm suspension
• swinging arm
• leaf springs
  • Two transverse leaf springs, or four quarter elliptics on one end of a car are similar to wishbones in geometry, but are more compliant. Examples are the front of the Panhard Dyna Z and the early examples of Peugeot 403 and the back of the AC Ace and AC Aceca.

Because the wheels are not constrained to remain perpendicular to a flat road surface in turning, braking and varying load conditions, control of the wheel camber is an important issue. Swinging arm was common in small cars that were sprung softly and could carry large loads, because the camber is independent of load. Some active and semi-active suspensions maintain the ride height, and therefore the camber, independent of load. In sports cars, optimal camber change when turning is more important. A swing axle suspension is a simple type of independent suspension used in automobiles. ... A sliding pillar suspension is one in which a wheel is positioned laterally and longitudinally by a circular piece which slides vertically along a simple rod (the pillar). ... A simple MacPherson strut suspension on the left front wheel of a rear-wheel drive vehicle. ... A Chapman strut is an automobile suspension device. ... This article or section does not cite its references or sources. ... A double wishbone suspension is an automobile independent suspension design using two parallel wishbone-shaped arms to locate the wheel. ... A multi-link suspension is a type of vehicle suspension design typically used in independent suspensions, using three or more lateral arms, and one or more longitudinal arms. ... A trailing-arm suspension is an automobile suspension design in which one or more arms (or links) are connected between (and perpendicular to) the axle and the chassis. ... A 1959 Panhard Dyna Z A rare Dyna Z pick-up The Panhard Dyna Z was one of the last Panhard cars to be made, perhaps the last (potentially) really important model. ... The Peugeot 403 was an automobile produced by the French manufacturer Peugeot from 1955 to 1966. ... The classic 1951-1962 AC Ace. ... The Aceca (pronounced A-See-Ka) was a closed coupe from AC Cars, produced from 1954 through 1963. ... 1963 Jaguar E-Type, a classic sports car 1963 Chevrolet Corvette was based upon European sports cars A sports car is an automobile designed for performance driving. ...

Wishbone and multi-link allow the engineer more control over the geometry, to arrive at the best compromise, than swing axle, MacPherson strut or swinging arm do; however the cost and space requirements may be greater. Semi-trailing arm is in between, being a variable compromise between the geometries of swinging arm and swing axle.

Armoured fighting vehicle suspension

This Grant I tank's suspension has road wheels mounted on wheel trucks, or bogies.

Military AFVs, including tanks, have specialized suspension requirements. They can weigh more than seventy tons and are required to move at high speed over very rough ground. Their suspension components must be protected from land mines and antitank weapons. Tracked AFVs can have as many as nine road wheels on each side. Many wheeled AFVs have six or eight wheels, to help them ride over rough and soft ground. Download high resolution version (1024x828, 113 KB)M3 Lee tank June 1942, Fort Knox Source: [1] Copyright: Library of Congress, Public Domain File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Download high resolution version (1024x828, 113 KB)M3 Lee tank June 1942, Fort Knox Source: [1] Copyright: Library of Congress, Public Domain File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... The M3 Lee was an American tank used during World War II. The British modified version of this tank, with a larger cast turret to house the radio, was called the Grant M3 tank History Used Australia Britain (600) Both Lee and Grant types, also modified Grant with armoured Searchlight... A bogie is a wheeled wagon or trolley. ... An armoured fighting vehicle (AFV) is a military vehicle, protected by armour and armed with weapons. ... “Minefield” redirects here. ... Anti-tank, or simply AT, refers to any method of combating military armored fighting vehicles, notably tanks. ... </nowiki> Rear sprocket of a Leclerc tank Track of a Leclerc tank U.S. M60 Patton tank. ... For other uses, see Wheel (disambiguation). ...

The earliest tanks of the Great War had fixed suspensions—with no movement whatsoever. This unsatisfactory situation was improved with leaf spring suspensions adopted from agricultural machinery, but even these had very limited travel. Ypres, 1917, in the vicinity of the Battle of Passchendaele. ... A traditional leaf spring arrangement. ...

Speeds increased due to more powerful engines, and the quality of ride had to be improved. In the 1930s, the Christie suspension was developed, which allowed the use of coil springs inside a vehicle's armoured hull, by redirecting the direction of travel using a bell crank. Horstmann suspension was a variation which used a combination of bell crank and exterior coil springs, in use from the 1930s to the 1990s. A British Comet with Christie suspension The Christie suspension is a suspension system developed by Walter Christie for his tank designs. ... A compression coil spring A tension coil spring A selection of conical coil springs A Coil spring, also known as a helical spring, is a mechanical device, which is typically used to store energy and subsequently release it, to absorb shock, or to maintain a force between contacting surfaces. ... A bell crank is a type of crank that changes motion around a 90 degree angle. ... Vickers Mark VI light tank, with suspension components visible. ...

By the Second World War the other common type was torsion-bar suspension, getting spring force from twisting bars inside the hull—this had less travel than the Christie type, but was significantly more compact. The torsion-bar suspension, sometimes including shock absorbers, has been the dominant heavy armored vehicle suspension since the Second World War. Mushroom cloud from the nuclear explosion over Nagasaki rising 18 km into the air. ... Torsion beam suspension, also known as a torsion bar or torsion spring suspension, is a vehicle suspension system. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000...

See also

• Automotive suspension design
• Bicycle fork
• Bicycle suspension
• Bump Steer
• Magnetic levitation and maglev train.
• Motorcycle fork
• Strut bar
• Suspension (motorcycle)
• Sway bar
• Wheel and wheel-less.

References

External links

Wikimedia Commons has media related to:

Automotive suspension technologies

• The Suspension Bible
• Bose Suspension System
• Kinetic news article
• Air Ride Suspension information
• Benefits of Adding Air Springs to a vehicle's suspension
• Camaro Suspension Modification
• Car Hydraulics