Lift-off oversteer is a form of oversteer in an automobile

Automobile

An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...

 that occurs when the vertical load on the tires shifts from the rear to the front quickly due to throttle

Throttle

A throttle is the mechanism by which the flow of a fluid is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases , but usually decreased. The term throttle has come to refer, informally and incorrectly, to any mechanism by which...

 release while cornering. This decrease in vertical load causes a decrease in the lateral force generated by the rear axle, so the axle starts to accelerate towards the outside of the turn. This steers the car more tightly into the turn, hence causing oversteer. In essence, this means that easing off the gas causes the rear wheels to break away suddenly, with the potential for the car to leave the road tail first.

Causes and countermeasures

This type of oversteer is often more pronounced in rear-engined cars and cars with swing axle

Swing axle

A swing axle is a simple type of independent suspension first used in early aircraft , such as the Sopwith and Fokker, usually with rubber bungee and no damping....

 rear suspension.
Rearward centers of gravity (such as older Porsche 911

Porsche 911

The Porsche 911 is a luxury 2-door sports coupe made by Porsche AG of Stuttgart, Germany. It has a distinctive design, rear-engined and with independent rear suspension, an evolution of the swing axle on the Porsche 356. The engine was also air-cooled until the introduction of the Type 996 in 1998...

s) enhance this effect, though technically any vehicle can experience lift-off oversteer. Various suspension enhancements, such as a Weissach axle

Weissach axle

The Weissach axle is a special rear suspension arrangement devised for the Porsche 928. The goal of the Weissach axle was to eliminate lift-throttle oversteer by allowing the rear suspension to adjust itself during cornering maneuvers....

, Passive rear wheel steering, or a multi-link suspension

Multi-link suspension

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....

, can limit a vehicle's tendency to oversteer in this situation. Even the handling of the Chevrolet Corvair

Chevrolet Corvair

-First generation :The 1960 Corvair 500 and 700 series four-door sedans were conceived as economy cars offering few amenities in order to keep the price competitive, with the 500 selling for under $2,000...

 improved in final years of production through the use of enhanced anti-roll bars

Sway bar

A sway bar or anti-roll bar or stabilizer bar is a part of an automobile suspension that helps reduce the roll of a vehicle that is induced by cornering or road irregularities. It connects opposite wheels together through short lever arms linked by a torsion spring...

, according to John DeLorean's book, On a Clear Day You Can See General Motors.

Dynamics

The graphs to the right show the simulated effect of lifting off the throttle in the middle of a left turn. The transients in the first couple of seconds are due to the test, in which a step steer input (wheel angle) is applied at 0 s and held constant throughout. The steady state cornering is at constant speed, with a lateral acceleration of 0.45 g approximately until the throttle is released at 6 s.

The yaw rate

Yaw rate

A yaw rotation is a movement around the yaw axis of a vehicle. It is commonly measured in degrees per second or radians per second.In the general case, is a quite different movement from an increment of its heading angle. Nevertheless, in vehicles that move on a plane like a car or a vessel, both...

 plot shows the oversteer due to the rear wheels losing traction - after an uncomfortable jerk at 20 deg/s, the vehicle spins sharply in the direction of the turn. The lateral acceleration also spikes to 0.6 g and levels at about 0.55 g, meaning that the radius decreased (i.e., the turn tightened). The side forces on the outside wheels increase and the inside rear (LR) wheel even lifts off the ground, a common occurrence.

In popular culture

In the 1940s, the Nazis described the Tatra automobile as the Czech Secret Weapon due to its treacherous and deadly lift-off oversteer handling characteristics.

Attorney and consumer protection activist Ralph Nader

Ralph Nader

Ralph Nader is an American political activist, as well as an author, lecturer, and attorney. Areas of particular concern to Nader include consumer protection, humanitarianism, environmentalism, and democratic government....

 described this type of handling in his 1965 book Unsafe at Any Speed

Unsafe at Any Speed

Unsafe at Any Speed: The Designed-In Dangers of the American Automobile by Ralph Nader, published in 1965, is a book detailing resistance by car manufacturers to the introduction of safety features, like seat belts, and their general reluctance to spend money on improving safety...

On April 10, 2010, Consumer Reports

Consumer Reports

Consumer Reports is an American magazine published monthly by Consumers Union since 1936. It publishes reviews and comparisons of consumer products and services based on reporting and results from its in-house testing laboratory. It also publishes cleaning and general buying guides...

 magazine rated the 2010 Lexus

Lexus

is the luxury vehicle division of Japanese automaker Toyota Motor Corporation. First introduced in 1989 in the United States, Lexus is now sold globally and has become Japan's largest-selling make of premium cars. The Lexus marque is marketed in over 70 countries and territories worldwide, and has...

 GX 460

Lexus GX

The Lexus GX is a mid-size sport utility vehicle sold in North American and Eurasian markets by Lexus. The first generation GX 470 was introduced at the North American International Auto Show in 2002 as a 2003 model, and subsequently became the third SUV to enter Lexus' lineup. The 4.7 L V8...

 SUV

Sport utility vehicle

A sport utility vehicle is a generic marketing term for a vehicle similar to a station wagon, but built on a light-truck chassis. It is usually equipped with four-wheel drive for on- or off-road ability, and with some pretension or ability to be used as an off-road vehicle. Not all four-wheel...

 a "Don’t Buy: Safety Risk." A panel of four automotive test engineer

Test Engineer

A hardware test engineer is a professional who determines how to create a process that would test a particular product in manufacturing, quality assurance or related area like RMA department, in order to assure that the product meets applicable specifications...

s determined that the vehicle was subject to excessive lift-off oversteer during a standardized evaluation for emergency handling. The test simulates scenarios such as transiting a highway

Highway

A highway is any public road. In American English, the term is common and almost always designates major roads. In British English, the term designates any road open to the public. Any interconnected set of highways can be variously referred to as a "highway system", a "highway network", or a...

 exit ramp

Interchange (road)

In the field of road transport, an interchange is a road junction that typically uses grade separation, and one or more ramps, to permit traffic on at least one highway to pass through the junction without directly crossing any other traffic stream. It differs from a standard intersection, at which...

 while traveling with excessive speed

Speed

In kinematics, the speed of an object is the magnitude of its velocity ; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as...

. On April 19, Toyota recalled the GX 460 and the Toyota Land Cruiser Prado for a software update

Software Update

Software Update is a software tool by Apple Inc. that installs the latest version of Apple software on computers running Mac OS X. It was originally introduced to Mac users in Mac OS 9. A Windows version has been available since the introduction of iTunes 7, under the name Apple Software Update....

 to the electronic stability control

Electronic stability control

Electronic stability control is a computerized technology that may potentially improve the safety of a vehicle's stability by detecting and minimizing skids. When ESC detects loss of steering control, it automatically applies the brakes to help "steer" the vehicle where the driver intends to go...

to correct the issue.