The Astatic was a French cyclecar manufactured from 1920 to 1922 by Automobiles Astatic, Saint-Ouen , Seine, France.
33-421: Built at Saint-Ouen, the car was an attempt to market a vehicle with independent suspension all round. This was done by coupling each wheel to a horizontal coil spring by a right angle link. At the rear the differential housing was fixed to the chassis and drive was taken to the wheels through jointed drive shafts. The engine was an 894 cc or 1100 cc S.C.A.P. This French history –related article
66-411: A shear force across it. The centrifugal (outwards) force is compensated for by applying negative camber, which turns the contact surface of the tire outwards to match, maximizing the contact patch area. Note that this is only true for the outside tire during the turn; the inside tire would benefit most from positive camber — again, only with a short long arms system. However, due to
99-399: A distinction can be drawn between systems where the spring also acts as a locating link and those where the spring only acts as a spring member. The AC Cobra is an example of a transverse, multi-leaf steel spring suspension that uses the leaf spring as the upper suspension arm. Alternatively, the 1963 Corvette 's rear suspension is an example where the transverse leaf spring is used only as
132-439: A ride spring. In both examples, the leaf spring is centrally mounted, preventing displacement of the wheel on one side from affecting the wheel on the other side. In 1981, General Motors pioneered the use of a FRP plastic transverse leaf spring on the third-generation Corvette . As in the examples above, the spring used a single, central mount which isolated the left and right movements. The FRP spring reduced weight and eliminated
165-413: Is a stub . You can help Misplaced Pages by expanding it . This article about classic and vintage automobiles produced between 1915 and 1930 is a stub . You can help Misplaced Pages by expanding it . 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
198-413: 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 wider definition considers any independent suspensions having three control links or more multi-link suspensions. These arms do not have to be of equal length, and may be angled away from their "obvious" direction. It was first introduced in the late 1960s on
231-417: Is allowed to pivot inside of the mounts which allows the displacement of the spring on one side to affect the other side. This mechanical communication between the left and right sides of the suspension results in an effect similar to that of an anti-roll bar . Chevrolet Corvettes, starting with the 4th generation in 1984 have combined the dual pivot mounts with FRP leaf springs . The transverse leaf spring
264-423: Is applied, the vehicle's tires will wear unevenly, a condition known as "camber wear". A suspension with excessive negative camber places more load on the inboard shoulder of the tire, causing the inboard shoulder to wear out quicker than the outboard shoulder. Depending on suspension design, a minor negative camber setting may slightly improve tire wear, as during turns the vehicle's center of gravity shifts toward
297-406: Is further out than the top, it is called negative camber . Camber angle alters the handling qualities of some suspension designs; in particular, negative camber improves grip in corners especially with a short long arms suspension . This is because it places the tire at a better angle to the road, transmitting the centrifugal forces through the vertical plane of the tire rather than through
330-729: Is not used as commonly as it was earlier. It is very rare on modern cars, the Corvette and a few Volvo models being examples. In the past it was more widely used in many Triumphs . The Herald , Vitesse , Spitfire , and GT6 all used a rear transverse leaf spring, as well as the 1995-98 Volvo 960/S90/V90 and a rare Swedish sports car incorporating the Volvo 960 rear suspension called the JC Indigo . This type of suspension should not be confused with earlier, rigid axle applications such as those used on early Ford cars . Camber angle Camber angle
363-406: Is one of the angles made by the wheels of a vehicle; specifically, it is the angle between the vertical axis of a wheel and the vertical axis of the vehicle when viewed from the front or rear. It is used in the creation of steering and suspension . If the top of the wheel is further out than the bottom (that is, tilted away from the axle), it is called positive camber ; if the bottom of the wheel
SECTION 10
#1733093643440396-442: Is the only component that separates the driver and/or passenger from the ground. The suspension in a vehicle helps absorb harshness in the road. There are many systems and designs that do this, such as independent suspension. This system provides many advantages over other suspension systems. For example, in solid axle suspension systems, when one wheel hits a bump, it affects both wheels. This will compromise traction, smoothness of
429-455: The differential unit does not form part of the unsprung elements of the suspension system. Instead, it is either bolted directly to the vehicle's chassis or more commonly to a subframe . The relative movement between the wheels and the differential is achieved through the use of swinging driveshafts connected via universal joints (U joints) , analogous to the constant-velocity (CV) joints used in front-wheel-drive vehicles. Suspension
462-426: The weight transfer inherent while turning, the outside wheels bear more of the force of turning and negative camber will improve handling overall. Caster angle will also compensate for this to a degree, as the top of the outside tire will tilt slightly inward, and the inner tire will respectively tilt outward. However, any camber affects the contact patch of the tire while driving in a straight line. Zero camber gives
495-539: The 1970s with the bōsōzoku cars coming out of Japan. This trend began with the intent of making street cars look more like race cars by lowering their suspension and adding a little negative camber. As time went by, such cars were being customarily lowered more and more, as well as having much more negative camber than before. With the growing of stance-car culture, it also attracted criticism, since extreme amounts of negative camber and minimal ground clearance can make these cars impractical. Accordingly they sometimes became
528-602: The Mercedes-Benz C111 prototype and put into production later on their W201 and W124 series. This is the most common, widely used front suspension system in cars today. It is a very simple and effective design that uses a strut-type spring and shock absorber that work as a team that will pivot on a single ball joint. This system was popularized in British Fords in the 1950s, then adopted by BMW (1962) and Porsche (1963). Later, this space-efficient system became widespread with
561-412: The ability of each wheel to address the road undisturbed by activities of the other wheel on the vehicle. Independent suspension requires additional engineering effort and expense in development versus a beam or live axle arrangement. A very complex IRS solution can also result in higher manufacturing costs. The key reason for lower unsprung weight relative to a live axle design is that, for driven wheels,
594-418: The adjustment will engender a change of up to two degrees. Control arms (or A-arms) with adjustable ball joints represent another avenue for allowing side-by-side adjustability. With these control arms installed, tire camber can effectively be changed by simply moving the tires. After that, one tightens the bolts in order to lock the ball joint in the desired position. Yet another aftermarket solution for changing
627-447: The best traction as it maximises the contact patch between the road and the tires and puts the tire tread flat on the road. Therefore excessive camber impairs straight driving in rain and snow and when accelerating hard. Proper management of camber angle is a major factor in suspension design, and must incorporate not only idealized geometric models, but also real-life behavior of the components; flex, distortion, elasticity, etc. What
660-442: The camber angle is via control rods of adjustable length. However, this solution is only amenable to vehicles which employ control rods, not A-arms. Because control rods (in vehicles so equipped) are responsible for locating the suspension points and keeping them in place, changing the overall length of the rods influences the camber angle. Off-road vehicles such as agricultural tractors generally use positive camber. In such vehicles,
693-443: The commonly modified models of cars. Some aftermarket coilovers come with built-in camber plates already in place, and there are certain other aftermarket solutions which allow the modification of the camber angle of the wheels. Camber bolts with eccentrics allow adjustable camber on some vehicles. These bolts feature large washers that are either eccentric or offset. If the original-equipment bolts are replaced with eccentric ones, then
SECTION 20
#1733093643440726-443: The factory. Negative camber was primarily used in motor sports due to the traction increase around turns. However, it eventually became popular to use negative camber in order to be able to lower a car and fit wheels on it which would not normally fit in the fender wells. Cars with these modifications eventually were given the name "stance cars". It is difficult to pinpoint when exactly this trend began, although it became mainstream in
759-685: The growing popularity of front-wheel drive vehicles. One problem with this system is that once the spring or the top plate becomes worn, the driver of a car with this system may hear a loud "clonk" noise at full lock (i.e. steering wheel turned to the extreme left or extreme right positions), as the strut's spring jumps back into place. This noise is often confused with CV-joint knock. Several independent suspension designs have featured transverse leaf springs. Most applications used multi-leaf steel springs, although more recent designs have used fiber reinforced plastic (FRP, typically fibers are fiberglass) springs. In addition to spring type (multi-leaf steel, FRP),
792-451: The inner leaf friction as compared to the multi-leaf metal spring which was standard on the car. Rather than centrally mounting the transverse leaf spring and thus isolating the left and right sides of the springs, some manufacturers, starting with Fiat used two widely spaced spring mounts. This was first used on the front of the 1955 Fiat 600 and later at the rear on the Fiat 128 . The spring
825-422: The name implies, has the rear wheels independently sprung. A fully independent suspension has an independent suspension on all wheels. Some early independent systems used swing axles , but modern systems use Chapman or MacPherson struts , trailing arms , multilink , or wishbones . Independent suspension typically offers better ride quality and handling characteristics, due to lower unsprung weight and
858-570: The others. This is contrasted with a beam axle or deDion axle system in which the wheels are linked. "Independent" refers to the motion or path of movement of the wheels or suspension. It is common for the left and right sides of the suspension to be connected with anti-roll bars or other such mechanisms. The anti-roll bar ties the left and right suspension spring rates together but does not tie their motion together. Most modern vehicles have independent front suspension ( IFS ). Many vehicles also have an independent rear suspension ( IRS ). IRS, as
891-497: The outside of the outer wheel. On a vehicle with zero camber this places load on the outboard shoulder of the tire, causing uneven wear over time. A small negative camber angle allows this load to be more evenly distributed across the tread. Positive camber will generally place more load on the outboard shoulder, causing it to wear more quickly than the inboard shoulder. This is among the many reasons vehicles are not typically aligned with extreme positive or negative camber settings from
924-513: The positive camber angle helps achieve a lower steering effort. Also, some single-engined general-aviation aircraft that are primarily meant to operate from unimproved surfaces, such as bush planes and cropdusters , have their taildragger gear's main wheels equipped with positive-cambered main wheels to better handle the deflection of the landing gear, as the aircraft settles on rough, unpaved airstrips. If excessive camber — either positive or negative —
957-443: The ride, and could also cause a dangerous wheel shimmy when moving at high speeds. With independent suspension systems, the bump primarily affects only the contacted wheel. This offers many advantages such as greater ride comfort, better traction, and safer, more stable vehicles on the road. In automobiles, a double wishbone suspension is an independent suspension design using two (occasionally parallel) wishbone-shaped arms to locate
990-427: The upper control arm or strut mounting points be altered to allow for some inward or outward movement, relative to the longitudinal centerline of the vehicle, for camber adjustment. With aftermarket plates containing slots for strut mounts instead of merely holes, this allows the entire shock absorber to be able to move back and forth, allowing for fine-tuning the camber of a vehicle. These plates are available for most of
1023-465: 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. A multi-link suspension
Astatic - Misplaced Pages Continue
1056-579: The whole vehicle lowers, the wheels are almost vertical. In cars with double wishbone suspensions , camber angle may be fixed or adjustable, but in MacPherson strut suspensions, it is normally fixed. The elimination of an available camber adjustment may reduce maintenance requirements, but if the car is lowered by use of shortened springs , the camber angle will change. Excessive camber angle can lead to increased tire wear and impaired handling. Significant suspension modifications may correspondingly require that
1089-403: Was once an art has become much more scientific with the use of computers, which can optimize all of the variables mathematically instead of relying on the designer's intuition and experience. As a result, the handling of even low-priced automobiles has improved dramatically. Heavy-duty vehicles, such as tractors, trucks, etc., tend to have more positive camber angle, so that when they are loaded and
#439560