 Ideally, when the car reaches the turn, the driver will steer it along the line marked with green dots. However, if the car is too 'tight', it will understeer, following the red dotted line and leaving the road. Understeer is a term for a car handling condition during cornering in which the circular path of the vehicle's motion is of a markedly greater diameter than the circle indicated by the direction its wheels are pointed. The effect is opposite to that of the oversteer and in simpler words understeer is the condition in which the front tires don't follow the trajectory the driver is trying to impose while taking the corner, instead following a more straight line trajectory. Image File history File links This is a lossless scalable vector image. ...
Image File history File links This is a lossless scalable vector image. ...
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. ...
The Trikke is a Human Powered Vehicle (HPV) This article is about the means of transport. ...
The force bearing on the axle has an eccentricity e with the point of contact to the rolling surface and exerts a moment about the contact point. ...
Ideally, when the car reaches the turn, the driver will steer it along the line marked with green dots. ...
This is also often referred to as pushing, plowing, or refusing to turn in. The car is referred to as being 'tight' because it is stable and far from wanting to spin.
As with oversteer, understeer has a variety of sources such as mechanical traction, aerodynamics and suspension.
Classically, understeer happens when the front tires have a loss of traction during a cornering situation, thus causing the front-end of the vehicle to have less mechanical grip and become unable to follow the trajectory in the corner. Traction usually refers to friction between a drive member and the surface it runs on, where friction is used to provide motion. ...
In modern race cars, especially open wheel cars, understeering is caused mainly due to the aerodynamic configuration. In this respect, the lack of a heavy aerodynamic load (downforce) in the front side prevents the front tires from gaining enough traction. At the same time understeer can be caused by having a heavier aerodynamic load at the rear end of the car giving the rear tires more traction than the front tires. Also, suspension balance should take into account the types of surfaces being driven - differing levels of friction in each surface influence the potential understeer behavior. Camber angles, ride height, tire pressure and centre of gravity are important factors that determine the understeer/oversteer handling condition. Auto racing (also known as automobile racing or autosport) is a sport involving racing automobiles. ...
Modern Formula One Renault 1993 Indy Car Open wheel car is a term for cars, usually purpose built racecars, with the wheels located outside the cars main body, as distinct from cars which have their wheels below the body or fenders, in the manner of most street cars, stock...
Automotive aerodynamics is the study of the aerodynamics of road vehicles. ...
Three different styles of front wings from three different Formula 1 eras, all designed to produce downforce on the front wheels. ...
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. ...
In physics, the center of gravity (CoG) of an object is the average location of its weight. ...
Understeer covers several different phenomena, in particular, there is a big difference between linear range understeer, typically between 0 and 0.4g, and limit handling understeer, which is at higher lateral accelerations, and is what racing drivers are talking about.
Common practice
It is common practice among automobile manufacturers to configure production cars deliberately to have a slight linear range understeer by default. If a car understeers slightly, it tends to be more stable (within the realms of a driver of average ability) if a violent change of direction occurs, improving safety. However, if the owner fits new tires to the front axle only they will tend to reduce the understeer margin, which can cause handling problems, as claimed in San Luis Obispo County Court Case CV078853, and others. [1]. The recommendation from most manufacturers when replacing only two tires is to fit the unworn ones to the rear, and the best of the old ones to the front axle, for this reason. However, this is not ideal either.
Physics Under all high speed (greater than approximately 10mph (16 km/h) for a typical automobile) cornering conditions a wheeled vehicle with pneumatic tires develops a greater lateral (i.e. sideslip) velocity than is indicated by the direction in which the wheels are pointed. The difference between the circle the wheels are currently tracing and the direction in which they are pointed is the slip angle. If the slip angles of the front and rear wheels are equal, the car is in a neutral steering state. If the slip angle of the front wheels exceeds that of the rear, the vehicle is said to be understeering. If the slip angle of the rear wheels exceeds that of the front, the vehicle is said to be oversteering. Karl Benzs Velo (vélo means bicycle in French) model (1894) - entered into the first automobile race 2005 MINI Cooper S. An automobile (also motor car or simply car) is a wheeled passenger vehicle that carries its own motor. ...
For a table of tire companies, see List of tire companies. ...
Ideally, when the car reaches the turn, the driver will steer it along the line marked with green dots. ...
An old bit of racing humor says that an understeering car goes through the fence nose first, an oversteering car goes through the fence tail first, and with a neutral-steering car, both ends go through the fence at the same time. “Racing cars†redirects here. ...
Design Any vehicle may understeer or oversteer at different times based on road conditions, speed, available traction, and driver input. The design of a vehicle, however, will tend to produce a particular "terminal" condition when the vehicle is pushed to and past its limits of adhesion. "Terminal understeer" refers to a vehicle which, as a function of its design, tends to understeer when cornering loads exceed tire traction.
Terminal handling balance is a function of front/rear relative roll resistance (suspension stiffness), front/rear weight distribution, and front/rear tire traction. A front-heavy vehicle with low rear roll stiffness (from soft springing and/or undersized or nonexistent rear anti-roll bars) will have a tendency to terminal understeer: its front tires, being more heavily loaded even in the static condition, will reach the limits of their adhesion before the rear tires, and thus will develop larger slip angles. Front-wheel drive cars are also prone to understeer because not only are they usually front-heavy, transmitting power through the front wheels also reduces their grip available for cornering. This often leads to a "shuddering" action in the front wheels which can be felt in the car as grip is suddenly being changed from planting the engines power on the road and steering. This is why rear wheel drive cars tend to handle better as the rear wheels main job is to handle the engines torque and the front wheels to steer. Helical or coil springs designed for tension A spring is a flexible elastic object used to store mechanical energy. ...
A sway bar (also called an anti-sway bar or anti-roll bar) is an automobile suspension device. ...
Front-wheel drive is the most common form of engine/transmission layout used in modern passenger cars, where the engine drives the front wheels. ...
Torque applied via an adjustable end wrench Relationship between force, torque, and momentum vectors in a rotating system In physics, torque (or often called a moment) can informally be thought of as rotational force or angular force which causes a change in rotational motion. ...
Although understeer and oversteer can each cause a loss of control, many automakers design their vehicles for terminal understeer in the belief that it is easier for the average driver to control than terminal oversteer. Unlike terminal oversteer, which often requires several steering corrections, understeer can often be reduced simply by reducing speed. A slight danger in some cars which traditionally understeer is actually sudden oversteer. So for example if a car is driving hard and understeering, the driver may be tempted to take his foot off the accelerator (increasing steering effectiveness of the front wheels as there is no engine torque to deal with) causing the car to snap oversteer and spin, often without warning. Not many production cars react like this, as it is not a desirable characteristic. Lift-off oversteer (also known as snap-oversteer, trailing-throttle oversteer, lift-throttle oversteer, or drop-throttle oversteer) is a form of oversteer in an automobile that occurs when the vertical load on the tires shifts from the rear to the front quickly due to throttle release while cornering. ...
Understeer is not just present during acceleration through a corner, it can also be found during heavy braking. If the brake balance (the strength of the brakes in terms of the front and rear wheels) is too heavy at the front this can cause understeer. This is caused by the front wheels locking and losing any effective steering. The opposite is true if the brake balance is too strong towards the rear wheels causing the rear end to spin out (like a child skidding on a bicycle). In ordinary road cars a safe brake balance (tending towards slight understeer) must be found.
Racing drivers, on asphalt surfaces, generally prefer a neutral condition (with a slight tendency toward understeer or oversteer, depending on the track and driver preference) because both understeer and oversteer conditions will scrub off speed while cornering. In rear wheel drive cars understeer is generally faster on a circuit because the rear wheels need to have some grip available to accelerate the vehicle out of the turn.
In a straight line, or when cornering gently (typically up to 0.4g) the characteristic is called linear range understeer. This is a difficult chracteristic to sense directly, but is responsible for many important facets of the handling in this regime, including step steer response, frequency response, and yaw gain linearity. Usually this is developed using a Bundorf analysis. A Bundorf analysis is a way of describing the characteristics of a vehicle that govern its understeer balance. ...
Understeer values How much a car understeers can be measured in the number of degrees more the steering wheel have to be turned per G of lateral acceleration. Here are the measured linear range values for some cars.[1] The higher the number the more the car understeers. The Nissan 350Z is a sports car manufactured by Nissan Motor Co, LTD. The 350Z is the fifth (and current) generation of Nissans Z-car line, originally introduced in 1970 as the Datsun 240Z. The 350Z entered production in late 2002 and was sold and marketed as a 2003...
The Mazda MX-5, also known as Miata (IPA: /miαrə/ or /miαtə/) in North America and Roadster (IPA: /lodostα/) in Japan, is a sports car built by Mazda in Hiroshima, Japan, since 1989. ...
The Nissan 350Z is a sports car manufactured by Nissan Motor Co, LTD. The 350Z is the fifth (and current) generation of Nissans Z-car line, originally introduced in 1970 as the Datsun 240Z. The 350Z entered production in late 2002 and was sold and marketed as a 2003...
The Ford Mustang is an automobile produced by the Ford Motor Company, originally based on the Ford Falcon compact. ...
The Renault Mégane is a compact automobile made by Renault. ...
The Maserati Gran Sport is equipped with a standard 4. ...
Minis The Mini is the name of a small car produced from 1959 to 2000, and the name of its replacement (known as New MINI) launched in 2001. ...
The BMW 3 Series is a line of mid-size sports sedan manufactured by BMW since May 1975. ...
The Alfa Romeo 147 is a small family car produced by Italian automaker Alfa Romeo since 2000. ...
The Chevrolet Corvette is the sixth and current generation of Chevrolet Corvettes built and marketed by Chevrolet. ...
The Chevrolet Corvette is a sports car first manufactured by Chevrolet in 1953 and is built today exclusively at a General Motors assembly plant in Bowling Green, Kentucky. ...
The Lotus Elise is a roadster conceived in early 1994 and released in September 1996 by the English manufacturer Lotus Cars. ...
The Porsche Type 997, or simply 997 (nine-nine-seven or nine-ninety-seven) is the project code name for the current version of the sports car Porsche 911, built by the German manufacturer Porsche since 2004. ...
The Saab 9-3 is a compact executive car produced by the automaker Saab in Trollhättan, Sweden, although the convertible (cabriolet) version is made under license in Austria. ...
The Å koda Octavia is a medium family car introduced in 1996 by the car manufacturer Å koda. ...
The Porsche Type 997, or simply 997 (nine-nine-seven or nine-ninety-seven) is the project code name for the current version of the sports car Porsche 911, built by the German manufacturer Porsche since 2004. ...
The Porsche Cayman is a mid-engine 2-seat sports car launched in the 2006 model year. ...
VW Golf Mk. ...
The Porsche Boxster is a convertible sportscar released in late 1996. ...
This article does not adequately cite its references or sources. ...
The Land Rover Range Rover is a four-wheel drive / luxury SUV produced by Land Rover in the United Kingdom, and first introduced in 1970. ...
This article or section is not written in the formal tone expected of an encyclopedia article. ...
The Mitsubishi Lancer is a compact car built by Mitsubishi Motors. ...
The 968 was an automobile sold by Porsche AG of Germany from 1992 to 1995 and marketed as the replacement for the Porsche 944. ...
The Audi RS4 is a high-performance version of the Audi A4, a compact executive car produced by German automaker Audi. ...
The BMW M5 is the high-performance version of the BMW 5-Series automobile made by BMW M GmbH. M5 versions of the E28, E34, E39 and E60 5-Series have been made. ...
The BMW Z4 is a rear-wheel drive sports car by the German automaker BMW, known as the E85 in roadster form and E86 in coupe form. ...
The BMW M3 is a sporty version of the popular compact BMW 3-Series automobile, made by BMW M. M3 models have been derived from the E30, E36 and E46 models. ...
See also Vauxhall Astra, Holden Astra, and Saturn Astra for the usage of the nameplate by other General Motors subsidiaries. ...
The BMW Z4 is a rear-wheel drive sports car by the German automaker BMW, known as the E85 in roadster form and E86 in coupe form. ...
For the high-performance version of the Impreza WRX, see the Subaru Impreza WRX STI The Subaru Impreza WRX, also colloquially known as a WRX (Rex) is a turbocharged version of the Subaru Impreza, an all-wheel drive automobile. ...
The Subaru Legacy is a mid-size car introduced by the Japanese manufacturer Subaru in February 1989 as a larger, upscale companion to the companys Leone/Loyale (which was known, in some countries, by its trim level only, Subaru GL). ...
The Volvo V70 is a mid-size station wagon. ...
The Audi A4 is a compact executive car produced by the German automaker Audi since 1995. ...
USDM Mercedes-Benz W211 Estate A Mercedes-Benz E-Class police cruiser in Hamburg, Germany. ...
The Audi A4 is a compact executive car produced by the German automaker Audi since 1995. ...
Porsche Cayenne S rear The Porsche Cayenne is a mid-size luxury SUV produced by the German automaker Porsche since 2002. ...
Look up smart in Wiktionary, the free dictionary. ...
Mercerdes-Benz SLK 200 (11/2004) The Mercedes-Benz SLK-Class is a small luxury 2-door roadster. ...
A TVR Tuscan sports car The TVR Tuscan is a sports car manufactured by TVR. Specifications Engine Five different inline six engine options were offered to customers. ...
Alfa Romeo 159 Sportwagon The Alfa Romeo 159 is a compact executive car produced by the Italian manufacturer Alfa Romeo since 2005. ...
1934 Morgan Super Sports 1936 Morgan F4 Open Tourer 1960 Morgan A Modern Morgan Aero 8 at the Scarsdale Concours Wikimedia Commons has media related to: Morgan vehicles The Morgan Motor Company is a British automobile manufacturer. ...
Notes - ^ "Listan!", Automobil.
See also 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. ...
In physics, the center of mass of a system of particles is a specific point at which, for many purposes, the systems mass behaves as if it were concentrated. ...
A Toyota Supra in drifting exhibition in Atlanta in 2005. ...
Electronic Stability Control (ESC) is the generic term for systems designed to improve a vehicles handling, particularly at the limits where the driver might lose control of the vehicle. ...
Fishtailing is a problem with rear wheel drive vehicles. ...
An inboard braking system is an automobile technology where the brakes are not located in the wheels, as is common today, but instead near the differential. ...
Ideally, when the car reaches the turn, the driver will steer it along the line marked with green dots. ...
Steering is the term applied to the collection of components, linkages, etc. ...
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. ...
For a table of tire companies, see List of tire companies. ...
This does not cite its references or sources. ...
Vehicle dynamics is the Dynamics of Vehicles, here assumed to be ground vehicles. ...
In automobiles, weight transfer (often confused with load transfer) refers to the redistribution of weight supported by each tire during acceleration (both longitudinal and lateral). ...
External Links - Effect of narrow rear track on understeer
|
Feeds |
Contact