A tire or tyre is a ring-shaped vehicle component that covers the wheels rim to protect it and enable better vehicle performance. Most tires, such as those for automobiles and bicycles, provide traction between the vehicle and the road providing a flexible cushion that absorbs shock. The materials of modern tires are synthetic rubber, natural rubber and wire, along with carbon black. They consist of a tread and a body, the tread provides traction while the body provides containment for a quantity of compressed air. Before rubber was developed, the first versions of tires were bands of metal fitted around wooden wheels to prevent wear and tear. Pneumatic tires are used on many types of vehicles, including cars, motorcycles, trucks, heavy equipment, and aircraft. Metal tires are used on locomotives and railcars, and solid rubber tires are still used in various non-automotive applications, such as some casters, lawnmowers. The etymology of tire is that the word is a form of attire. The spelling tyre does not appear until the 1840s when the English began shrink fitting railway car wheels with malleable iron, traditional publishers continued using tire.
The Times newspaper in Britain was still using tire as late as 1905, the spelling tyre began to be commonly used in the 19th century for pneumatic tires in the UK. However, over the course of the 20th century, tyre became established as the standard British spelling, the earliest tires were bands of leather, placed on wooden wheels, used on carts and wagons. The tire would be heated in a fire, placed over the wheel and quenched, causing the metal to contract. A skilled worker, known as a wheelwright, carried out this work, the outer ring served to tie the wheel segments together for use, providing a wear-resistant surface to the perimeter of the wheel. The word tire thus emerged as a variant spelling to refer to the bands used to tie wheels. The first patent for what appears to be a standard pneumatic tire appeared in 1847 lodged by the Scottish inventor Robert William Thomson, this never went into production. The first practical pneumatic tire was made in 1888 on May Street, Belfast, by Scots-born John Boyd Dunlop and it was an effort to prevent the headaches of his 10-year-old son Johnnie, while riding his tricycle on rough pavements.
His doctor, Sir John Fagan, had prescribed cycling as an exercise for the boy, Fagan participated in designing the first pneumatic tires. In Dunlops tire patent specification dated 31 October 1888, his interest is only in its use in cycles, in September 1890, he was made aware of an earlier development but the company kept the information to itself
The Chapman strut is a design of independent rear suspension used for light cars, particularly sports and racing cars. It takes its name from, and is best known for its use by, the designs origin lies with William Stouts 1932 Stout Scarab. This rear-engined car used swing axle independent rear suspension, with long near-vertical coilover struts from high mounting points on the space frame chassis. Stout had been a designer and considered that the long-travel oleo struts made. The lower ends of the struts were attached to the axle casings by swivel bushes. Forward radius rods handled the longitudinal forces, in 1947 Earle MacPherson patented the MacPherson strut for use on the Chevrolet Cadet. New car designs were lighter and faster than pre-war cars, drivers demanded roadholding and comfort that required independent front suspension. MacPhersons strut was cheap to manufacture and reliable in service, having few moving joints and using the new shock absorbers. The MacPherson strut appears to have had influence on Chapman at this time.
Double wishbone suspension was already well-established for the front of high-performance cars, a front strut would have required much greater height than was available in a racing car. In 1957, the lightweight Goggomobil used a suspension design to the Scarab. Much simpler though, the Goggomobil had bare drive shafts that acted as the suspension links, the swing axle shafts were only carried by the trailing radius rods, rather than an axle casing, and the long struts were shortened to a simple coilover shock absorber. In 1956 Chapman was using de Dion rear axles for his Lotus racing cars and these had initially used transverse leaf springs, but changed to coilover shock absorbers. The first Lotus Twelve Formula 2 cars used the same system, at a 750 Motor Club meeting in 1957, Chapman saw the Goggomobil system and was impressed by its Lotus-like simplicity and light weight. The use of the shafts for both drive and as a suspension component appealed to Chapman, who always favoured solutions that could make one component do double duty.
Chapman struts were introduced in Lotus first single-seater car, the Lotus Twelve and this was developed as a 1. 5-litre Formula 2 in 1957, but re-engined in 1958 it competed in Formula 1. This same car introduced Lotus wobbly-web wheel, there were two differences from these precursors to the Chapman strut. As the Lotus Twelve had inboard disk brakes, there was no need to pass the braking torque through the radius rods, Chapman avoided the swing axle and its camber changes with suspension travel, in favour of a drive shaft with two universal joints
A vehicle frame 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 a structural frame and this construction design is known as body-on-frame. Over time, nearly all cars have migrated to unibody construction, meaning their chassis. Nearly all trucks and most pickups continue to use a frame as their chassis. The main functions of a frame in motor vehicles are, To support the mechanical components and body To deal with static and dynamic loads. These include, Weight of the body and cargo loads and torsional twisting transmitted by going over uneven surfaces. Transverse lateral forces caused by conditions, side wind. Torque from the engine and transmission, longitudinal tensile forces from starting and acceleration, as well as compression from braking. In the case of a chassis, the frame is made up of structural elements called the rails or beams. These are ordinarily made of steel sections, made by folding, rolling or pressing steel plate.
There are three designs for these. If the material is folded twice, an open-ended cross-section, either C-shaped or hat-shaped results and it is made by taking a flat piece of steel and rolling both sides over to form a c-shaped beam running the length of the vehicle. Hat Hat frames resemble a U and may be either right-side-up or inverted with the area facing down. Not commonly used due to weakness and a propensity to rust, however they can be found on 1936–1954 Chevrolet cars, abandoned for a while, the hat frame gained popularity again when companies started welding it to the bottom of unibody cars, in effect creating a boxed frame. Boxed Originally, boxed frames were made by welding two matching C-rails together to form a rectangular tube, modern techniques, use a process similar to making C-rails in that a piece of steel is bent into four sides and welded where both ends meet. While appearing at first glance as a form made of metal. The first issue addressed is beam height, or the height of the side of a frame.
The taller the frame, the better it is able to resist vertical flex when force is applied to the top of the frame and this is the reason semi-trucks have taller frame rails than other vehicles instead of just being thicker
Simca was a French automaker, founded in November 1934 by Fiat and directed from July 1935 to May 1963 by Italian Henri Théodore Pigozzi. Simca was affiliated with Fiat and then, after Simca bought Fords French activities, in 1970, Simca became a subsidiary and brand of Chrysler Europe, ending its period as an independent company. Simca disappeared in 1978, when Chrysler divested its European operations to another French automaker, PSA replaced the Simca brand with Talbot after a short period when some models were badged as Simca-Talbots. During most of its activity, Simca was one of the biggest automobile manufacturers in France. For instance the Simca 1307 was sold in Britain as the Chrysler Alpine, Simca vehicles were manufactured by Simca do Brasil in São Bernardo do Campo and Barreiros in Spain. They were assembled in Australia, Chile and the Netherlands during the Chrysler era, Henri Théodore Pigozzi was active in the automotive business in the early 1920s when he met Fiat founder, Giovanni Agnelli.
They began business together in 1922 with Pigozzi acting as a merchant, buying old automobile bodies. Two years Pigozzi became Fiats General Agent in France, in 1928, SAFAF started the assembly of Fiat cars in Suresnes near Paris, and licensed the production of some parts to local suppliers. By 1934, as many as 30,000 Fiat cars were sold by SAFAF, the SIMCA company was founded in 1935 by FIAT, when Fiat bought the former Donnet factory in the French town of Nanterre. The first cars produced were Fiat 508 Balillas and Fiat 518 Arditas and they were followed during 1936 by the Simca Cinq or 5CV, a version of the Fiat Topolino announced in the Spring, but only available for sale from October 1936. The Huit, an 8CV version of the Fiat 508C-1100, appeared in 1937, production of the 6CV and 11CV stopped in 1937, leaving the 5CV and the 8CV in production until the outbreak of World War II. The firm nevertheless remained closely connected with Fiat, and it was not until 1938 that the shortened name Simca replaced Simca-Fiat, of the businesses that emerged as Frances big four auto-makers after the war, Simca was unique in not suffering serious bomb damage to its plant.
Despite France being occupied, Simca cars continued to be produced in numbers throughout the war. Nevertheless, shortly after the liberation the Nanterre plants financial sustainability received a boost when Simca won a contract from the American army to repair large numbers of Jeep engines, on 3 January 1946 the new government’s five-year plan for the automobile industry came into force. Grégoire owed his influence to a powerfully persuasive personality and an engineering talent. Regarding the future of the French automobile industry, Grégoire held strong opinions, a few weeks after the liberation Grégoire joined the Simca board as General Technical Director, in order to prepare for the production of the AFG at the company’s Nanterre factory. For Simca, faced with a determinedly dirigiste left-wing French government, in return, Grégoire obtained the personal commitment of the surviving Director General to the production at Nanterre of his two-door AFG. It is very easy to see how the two-door AFG looked, because its four-door equivalent went into production, little changed from Grégoire’s prototype and it was a car designed by an engineer, and Pigozzi thought it ugly
A spring is an elastic object used to store mechanical energy. Springs are usually out of spring steel. There are a number of spring designs, in everyday usage the term often refers to coil springs. When a spring is compressed or stretched from its resting position, the rate or spring constant of a spring is the change in the force it exerts, divided by the change in deflection of the spring. That is, it is the gradient of the force versus deflection curve, an extension or compression springs rate is expressed in units of force divided by distance, for example lbf/in or N/m. A torsion spring is a spring that works by twisting, when it is twisted about its axis by an angle, a torsion springs rate is in units of torque divided by angle, such as N·m/rad or ft·lbf/degree. The inverse of spring rate is compliance, that is, if a spring has a rate of 10 N/mm, the stiffness of springs in parallel is additive, as is the compliance of springs in series. Springs are made from a variety of materials, the most common being spring steel.
Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel, some non-ferrous metals are used including phosphor bronze and titanium for parts requiring corrosion resistance and beryllium copper for springs carrying electrical current. Simple non-coiled springs were used throughout history, e. g. the bow. In the Bronze Age more sophisticated spring devices were used, as shown by the spread of tweezers in many cultures, coiled springs appeared early in the 15th century, in door locks. The first spring powered-clocks appeared in that century and evolved into the first large watches by the 16th century, in 1676 British physicist Robert Hooke discovered Hookes law which states that the force a spring exerts is proportional to its extension. Compression spring – is designed to operate with a compression load, flat spring – this type is made of a flat spring steel. Machined spring – this type of spring is manufactured by machining bar stock with a lathe and/or milling operation rather than a coiling operation, since it is machined, the spring may incorporate features in addition to the elastic element.
Machined springs can be made in the load cases of compression/extension, torsion. Serpentine spring - a zig-zag of thick wire - often used in modern upholstery/furniture, the most common types of spring are, Cantilever spring – a spring which is fixed only at one end. Coil spring or helical spring – a spring is of two types, Tension or extension springs are designed to become longer under load and their turns are normally touching in the unloaded position, and they have a hook, eye or some other means of attachment at each end. Compression springs are designed to become shorter when loaded and their turns are not touching in the unloaded position, and they need no attachment points
Honda Civic Type R
The Honda Civic Type R is the highest performance version of the Honda Civic made by Honda Motor Company of Japan. It features a lightened and stiffened body, specially tuned engine and upgraded brakes, Red is used in the interior to give it a special sporting distinction and to separate it from other Honda models. The first Civic to receive the Type R name was based on the 6th-generation fan-base EK Civic, the contributing base model was the JDM Civic 3-door hatchback called SiR, code named EK4. The first Civic to receive the Type R badge was introduced in August 1997, the B16B engine boasted one of the highest power output per litre of all time for a naturally-aspirated engine with 185 PS from 1. 6L of engine displacement. For the first time, a seam welded monocoque chassis was used to improve chassis rigidity. The interior featured red seats, red cards, red Type R floor mats, a titanium shift knob. In 1998, the Civic Type R Motor Sports edition was released and it came with steel wheels, no air conditioning, no power windows, no power steering, no radio, and came with the standard Type R interior.
In 2001 Honda introduced the next generation of the Civic Type R as a unique 3-door hatchback to the UK market and this EDM Civic Type R featured a 200 PS2. However, Honda of Japan marketed a JDM version of the EP3, all of the Japan-spec K20A Type-R powertain were built in Japan and shipped to the Swindon plant to be installed in the Japan-spec Type-R EP3. The JDM EP3 was available in the traditional Type R championship white while the EDM was not, the EDM has more relaxed gear ratios and some high rpm torque traded for low rpm torque compared to the JDM. The JDM Civic was said to be the better of the two, the EDM EP3 Civic Type R was much acclaimed by motoring journalists across the UK, winning Hot Hatch of the Year awards more than once from Top Gear, Fifth Gear and What Car. The Civic Type R became an alternative for mainstream drivers clocking huge sales numbers. The base price for the 2001 Civic Type R in the United Kingdom was of £23,100, performance 0–60 mph in 5, 8/5, 8seconds,5, 8/5, 8secs 0–100 mph in 15.
In 2003 –2004 facelift and pre facelift Honda decided to celebrate 30 years of producing the Civic by offering a special edition 30th Anniversary Type-R. The special edition features special red and black sports seats Type R from world-renowned seat maker Recaro, air conditioning and it has a lighter fly-wheel and clutch. The JDM addition has red bucket seats from Recaro, red carpet and door cards, a leather MOMO steering wheel, 30th Anniversary models were available in Nighthawk Black, Satin Silver and Milano Red and the JDM addition comes in championship white. Only 300 of these models were produced,100 in each colour and they were available in Milano Red, Nighthawk Black, Cosmic Grey and Satin Silver. The Japanese market Civic Type R went on sale on March 30,2007, for the first time, the JDM Civic Type R was sold as a four-door sports sedan rather than a three-door hot hatch
The Stout Scarab is a 1930–1940s American minivan designed by William Bushnell Stout and manufactured by Stout Engineering Laboratories and by Stout Motor Car Company of Detroit, Michigan. Stout, president of the Society of Automotive Engineers, had met Buckminster Fuller at a major New York auto show, the front-mounted engine typically drove the rear axle through a connecting drive shaft running underneath the floor of the vehicle. This layout worked well, but had space limitations, the car’s creator and aviation engineer and journalist William B. Stout, envisioned his traveling machine to be an office on wheels, to that end, the Scarabs body, styled by John Tjaarda, a well known Dutch automobile engineer, closely followed the construction of an aluminium aircraft fuselage. Although reminiscent of the Chrysler Airflow and the slightly KdF-Wagen — all aerodynamically efficient in appearance, today its futuristic design and curvaceous, finely detailed nose earn it respect as an Art Deco icon.
Passengers entered through a single, large common door, a flexible seating system could be easily reconfigured, except for the drivers seat, which was fixed. Anticipating the seating in modern minivans, such as the Chrysler Voyager and Renault Espace, interiors were appointed in leather and wood. Design elements worked in a stylized ancient Egyptian scarab motif, visibility to the front and sides was similar to that of an observation car, although rearward vision was negligible and there were no rear-view mirrors. The innovations did not end with the layout and body design. In an era where almost everything on the road had rigid axles with leaf springs, the rear-engine-induced weight bias coupled to the coil spring suspension endowed the Scarab with very good handling and traction. The rear swing axle suspension with coil spring struts was inspired by aircraft landing gear. The Scarab suspension itself inspired the Chapman strut used by Lotus from their Lotus Twelve model of 1957, the Ford flathead V8 drove the rear wheels via a custom Stout-built three-speed manual transaxle.
The engine was reversed from its position, mounted directly over the rear axle and with the flywheel. The transmission was mounted ahead of this and lowering the back to the axle. This unusual layout would be repeated by the Lamborghini Countach, the first running prototype of the Scarab was completed in 1932, probably the first car ever with an aluminum spaceframe unit-construction body, although the frame parts were steel. The second Scarab, completed in 1935, was an evolution of the first, incorporating some styling and mechanical changes. The headlamps were set behind a fine, vertical-bar grille, and at the rear, narrow chrome bars curved from the window down to the bumper. The body was now steel to reduce cost, Stout issued a statement that the car would be manufactured in limited quantities and sold to those who were invited to buy
With global headquarters at the Renaissance Center in Detroit, United States, GM manufactures cars and trucks in 35 countries. In 2008,8.35 million GM cars and trucks were sold globally under various brands, current auto brands are Buick, Chevrolet, GMC, and Wuling. Former GM automotive brands include McLaughlin, Oldsmobile, Hummer, Saturn, the company was founded by William C. Durant on September 16,1908 as a holding company. The company was the largest automobile manufacturer from 1931 through 2007, in addition to brands selling assembled vehicles, GM has had various automotive-component and non-automotive brands, many of which it divested in the 1980s through 2000s. General Motors produces vehicles in 37 countries under twelve brands, Buick, GMC, Holden, HSV, Vauxhall, Baojun, Jie Fang, and Ravon. The current company, General Motors Company LLC, was formed in 2009 following the bankruptcy of General Motors Corporation, the new company purchased the majority of the assets of the old GM, including the brand General Motors.
In addition to its twelve brands, General Motors holds a 20% stake in IMM, General Motors employs 212,000 people and does business in more than 140 countries. General Motors is divided into five segments, GM North America, Opel Group, GM International Operations, GM South America. General Motors led global vehicle sales for 77 consecutive years from 1931 through 2007, longer any other automaker. General Motors acts in most countries outside the U. S. via wholly owned subsidiaries, GMs OnStar subsidiary provides vehicle safety and information services. In 2009, General Motors shed several brands, closing Saturn and Hummer, in 2010, the reorganized GM made an initial public offering that was one of the worlds top five largest IPOs to date, and returned to profitability that year. General Motors Corporation was formed on September 16,1908, in Flint, Michigan, GMs co-founder was Charles Stewart Mott, whose carriage company was merged into Buick prior to GMs creation. Over the years, Mott became the largest single stockholder in GM, and spent his life with his Mott Foundation, GM acquired Oldsmobile that year.
In 1909, Durant brought in Cadillac, Oakland, in 1909, GM acquired the Reliance Motor Truck Company of Owosso and the Rapid Motor Vehicle Company of Pontiac, the predecessors of GMC Truck. Durant, along with R. S. McLaughlin, lost control of GM in 1910 to a bankers trust, because of the amount of debt taken on in its acquisitions. The next year, Durant started the Chevrolet Motor Car Company in the U. S. and in Canada in 1915, Durant took back control of the company after one of the most dramatic proxy wars in American business history. Durant reorganized General Motors Company into General Motors Corporation in 1916, merging Chevrolet with GM, shortly thereafter, he again lost control, this time for good, after the new vehicle market collapsed. These facilities were added to the factories that were exclusive to Cadillac, Oldsmobile, Oakland
Car drifting is caused when the rear slip angle is greater than the front slip angle, to such an extent that often the front wheels are pointing in the opposite direction to the turn. The desired line is usually dictated by the judge or judges, although the origin of drifting is not known, Japan was one of the birthplaces of drifting as a sport. It was most popular in the All Japan Touring Car Championship races, the famous motorcyclist turned driver, Kunimitsu Takahashi, was the foremost creator of drifting techniques in the 1970s. This earned him several championships and a legion of fans who enjoyed the spectacle of smoking tires, the bias ply racing tires of the 1960s-1980s lent themselves to driving styles with a high slip angle. As professional racers in Japan drove this way, so did the street racers, Keiichi Tsuchiya, known as the Drift King, became particularly interested by Takahashis drift techniques. Tsuchiya began practicing his skills on the mountain roads of Japan. In 1987, several popular car magazines and tuning garages agreed to produce a video of Tsuchiyas drifting skills, the video, known as Pluspy, became a hit and inspired many of the professional drifting drivers on the circuits today.
In 1988, alongside Option magazine founder and chief editor Daijiro Inada and he drifted every turn in Tsukuba Circuit in Japan. One of the earliest recorded drift events outside Japan was in 1996, held at Willow Springs Raceway in Willow Springs, hosted by the Japanese drifting magazine and organization Option. Daijiro Inada, the NHRA Funny Car drag racer Kenji Okazaki, rhys Millen and Bryan Norris being two of the entrants. Drifting has since exploded into a form of motorsport in North America, Asia, Drifting has evolved into a competitive sport where drivers compete to earn points from judges based on various factors. At the top levels of competition, the D1 Grand Prix in Japan pioneered the sport, the drivers within these series were are able to keep their cars sliding for extended periods of time, often linking several turns. Drifting competitions are judged based on line, speed, line involves taking the correct line, which is usually announced beforehand by judges. The show factor is based on things, such as the amount of smoke, how close the car is to the wall or designated clipping point.
Angle is the angle of a car and more importantly the wheels in a drift, speed is the speed entering a turn, the speed through a turn. Style is scored on a combination of a rate-to-angle during the initiation, how fluid the car looks through the course, the rate-to-angle is how quickly during initiation or Furidashi and transitions or Furikaeshi a car gets to its sliding angle. Commitment is about how much throttle the driver applies, and the confidence and dedication the driver shows when approaching track edges, the judging takes place on just a small part of the circuit, a few linking corners that provide good viewing, and opportunities for drifting. The rest of the circuit is irrelevant, except as it pertains to controlling the temperature of the tires, there are typically two sessions - a qualifying/practice session, and a final session
In automotive suspension, a control arm, known as an A-arm, is a hinged suspension link between the chassis and the suspension upright or hub that carries the wheel. The inboard end of an arm is attached by a single pivot. It can thus control the position of the end in only a single degree of freedom. Although not deliberately free to move, the single bushing does not control the arm from moving back and forth and this is in contrast to the wishbone. Wishbones are triangular and have two widely spaced inboard bearings and these constrain the outboard end of the wishbone from moving back and forth, controlling two degrees of freedom, and without requiring additional links. Most control arms form the link of a suspension. A few designs use them as the link, usually with a lower wishbone. The additional radius rod is attached to the upper arm. Control arms are most commonly encountered as part of the MacPherson strut independent front suspension, the control arms are perpendicular to the axis of the vehicle and are termed track control arms.
A diagonal radius rod constrains the strut from moving forward and back, in MacPhersons original design, an anti-roll bar acted as the radius rod. This requires the bar to be attached through a ball joint, in most contemporary designs, still commonly termed MacPherson struts, the radius rod and anti-roll bar are now separate, with the anti-roll bar mounted in a sliding bush. A control arm may be used to carry the suspension load, torsion bar suspension commonly does this, with the outboard end of the torsion bar attached to the inboard bearing of the control arm
Cottin & Desgouttes
Cottin & Desgouttes was a French automobile manufacturer from the beginning of the 20th century. In 1904, Pierre Desgoutte started manufacturing automobiles under the name “Desgouttes & Cie”, in Lyon, the first model was the type A, powered by a 9. 5-liter,45 hp, six-cylinder engine. Only two cars of type were built. In December 1905, a chassis with a four-cylinder, 24/40 hp engine was presented at the Salon de Paris and it exhibited many innovative features and enjoyed a huge success. At the beginning of 1906, Pierre Desgoutte was joined by an industrial partner. They decided to call the new company “Automobiles Cottin & Desgouttes”, Pierre Desgoutte acting as Technical Director, the company progressively specialized in luxury and sports models. Between 1906 and 1914, most of the production was devoted to four-cylinder models, en 1907, the company produced a 2.5 liter,12 hp model that was so well accepted by the public that it was produced without any major changes for more than four years.
Over the next years, growth was regular and the factories thrived. In 1913, Cottin & Desgouttes could be proud of producing close to 450 cars with a staff of 300. The fame of Cottin & Desgouttes was due to their participation in a number of car races, as soon as May 1906, a Cottin & Desgouttes car driven by engineer Auguste Fraignac won the Limonest race in its category. Cyrille Cottin, a great sportsman himself, drove at a number of races, rallies or other sports events, at the beginning of World War I, the company produced a series of fast Utility Vehicles and delivered several large 36 hp “Torpedoes” to the French Army General Staff. The reliability of the used by the Army was legendary. During the war, Cottin & Desgouttes built engines for tractors. In 1915 the Cottin & Desgouttes factory manufactured aircraft motors for Gnome et Rhône, at the end of the War, Cottin & Desgoutte had well equipped production facilities, and their financial situation was good enough to start again producing luxury cars.
Their staff, accustomed to high quality standards, easily moved from the production back to tourist cars. The manufacturing of trucks was continued, in addition to the powerful models built immediately after the war, the company launched a smaller, all new and lower priced car in 1922, the type M. Shortly after this car was presented, Pierre Desgoutte quit the company, paul Joseph, selected by Cottin to replace him, was charged with building a more powerful and faster car, based on the type M, and aimed at racing. One such car won the Grand Prix du Tourisme de lAutomobile Club de France, in 1925, the company launched the “Sans Secousse”, with Houdaille-type paddle-based shock absorbers and separate springs for the 4 wheels
Kingpin (automotive part)
The kingpin, king-pin and king pin, is the main pivot in the steering mechanism of a car or other vehicle. The term is used to refer to part of a fifth wheel coupling apparatus. Originally, with the steering of horse-drawn wagons, this was a single pin on which the moveable axle was pivoted beneath the wagons frame. This located the axle from side to side, but the weight of the wagon was carried on a wooden ring turntable surrounding this. Similar centre pivot steering was used by traction engines, the kingpin being mounted on the perch bracket beneath the boiler. Some early cars used centre pivot steering, although it became apparent that it was unsuitable for their increasing speeds, ackermann steering separates the steering movement into two pivots, one near the hub of each front wheel. The beam axle between them remains fixed relative to the chassis, linked by the suspension, the kingpins were now fixed to the axle ends and the hub carriers pivoted upon them. Kingpins were always clamped in the centre and the bearings at the ends, to increase the lever arm.
Independent front suspension developed through the 1930s, for cars at least. This performance encouraged the reduction of unsprung weight, the hub carrier extended vertically to span the ends of both wishbones, with a ball joint at each end. In the 1950s and 1960s, such independent suspension became commonplace through light cars in all price ranges, although the kingpin was no longer an identifiable physical component, suspension geometry was still designed in terms of a virtual kingpin along a line between the ball joint centres. Although they are obsolete, kingpin suspensions have the advantage of being able to carry much heavier weights. Dana produced the king pin version of the D60 axle until 1991 and this virtual king pin angle remains a fundamental design parameter. King pin angle, virtual or physical, is referred to as its acronym KPA, or alternatively king pin inclination, or steering axis inclination. On most modern designs, the angle is set relative to the true vertical line. Kingpin inclination is non-adjustable, since it would change if the wheel spindle or steering knuckles are bent.
This has an important effect on the steering, making it tend to return to the straight ahead or centre position, a second effect of the kingpin inclination is to set the scrub radius of the steered wheel. This is the offset between the contact point with the road surface and the projected axis of the steering down through the kingpin