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Fishtailing is a
Fishtailing is a vehicle handling
Automobile handling and vehicle handling are descriptions of the way a wheeled vehicle responds and reacts to the inputs of a driver, as well as how it moves along a track or road. It is commonly judged by how a vehicle performs particularly duri ...
problem which occurs when the rear wheels lose traction, resulting in oversteer
Understeer and oversteer are vehicle dynamics terms used to describe the sensitivity of the vehicle to changes in steering angle associated with changes in lateral acceleration. This sensitivity is defined for a level road for a given steady state ...
. This can be caused by low-friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of t ...
surfaces (sand, gravel, rain, snow, ice, etc.). Rear-drive vehicles with sufficient power can induce this loss of traction on any surface, which is called power-oversteer.
Mechanics and causes
Accidental fishtailing
During fishtailing, the rear end of the car skids to one side, which must be offset by the driver counter-steering, which is turning the front wheels in the same direction as the skid, (e.g. left if the rear swings left) and reducing engine power. Over-correction will result in a skid in the opposite direction; hence the name. Without a proper driver's reaction, the fishtailing vehicle will spin completely. Friction is the main reason this action is effective. If a car is moving across a surface in any direction other than the direction it is pointed, it is skidding (or sliding), and a sideways load is being imposed against the tires. This causes a lot of friction, even if the tires are allowed to rotate freely. The ability of the rearsuspension
Suspension or suspended may refer to:
Science and engineering
* Car suspension
* Cell suspension or suspension culture, in biology
* Guarded suspension, a software design pattern in concurrent programming suspending a method call and the calling ...
to keep tires in contact with, and perpendicular to the road is also a key factor in the amount of grip available through the rear axle
An axle or axletree is a central shaft for a rotation, rotating wheel and axle, wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In ...
. For example, a live beam axle
A beam axle, rigid axle, or solid axle is a suspension (vehicle), dependent suspension design in which a set of wheels is connected laterally by a single beam or shaft. Beam axles were once commonly used at the rear wheels of a vehicle, but hist ...
suspension will have far less grip on a bumpy road than an independent rear 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 the others. This is contrasted with a beam axle or deDion axle system in ...
, due to its far greater unsprung weight
The unsprung mass (colloquially unsprung weight) of a vehicle is the mass of the suspension, wheels or tracks (as applicable), and other components directly connected to them. This contrasts with the sprung mass (or weight) supported by the ...
and forces from one wheel being transmitted through the axle to the other wheel, leading to the tire being out of contact with the road surface more of the time.
PIT maneuver
Fishtailing may be the result of the police pursuit technique called thePIT maneuver
The PIT maneuver (precision immobilization techniqueRaviv, Shaun, and John Sullivan"Police driving maneuver used to end chases has killed 30 people since 2016, The Post finds", ''Washington Post'', August 24, 2020. Retrieved 2020-08-24.), al ...
, in which the driver of a pursuing vehicle deliberately induces directional instability in a pursued vehicle with the intent of spinning it off the road.
Solutions
By turning the front wheels into the direction of the skid, the front wheels will become aligned with the direction of travel. The side load will no longer be imposed against the front tires, and they will then roll freely to match the speed of the vehicle. This reduces the friction between the front tires and the surface. The rear tires will still be sliding sideways, and the greater friction that exists will cause the back end to trail directly behind the front end, similar to ashuttlecock
A shuttlecock (also called a birdie or shuttle, or ball) is a high-drag projectile used in the sport of badminton. It has an open conical shape formed by feathers or plastic (or a synthetic alternative) embedded into a rounded cork (or ru ...
in flight; thus the car straightens out. As the car straightens, the front wheels must be kept aligned with the direction the vehicle is moving, not the direction it is pointed, to keep the friction of the front tires at or below the friction of the rear tires, or a skid in the opposite direction will quickly develop.
Most modern rear-wheel-drive cars solve this problem by using a form of traction control
A traction control system (TCS), is typically (but not necessarily) a secondary function of the electronic stability control (ESC) on production motor vehicles, designed to prevent loss of traction (i.e., wheelspin) of the driven road wheels. TCS ...
, such as anti-lock brakes
An anti-lock braking system (ABS) is a safety anti- skid braking system used on aircraft and on land vehicles, such as cars, motorcycles, trucks, and buses. ABS operates by preventing the wheels from locking up during braking, thereby maintai ...
, which limits engine power when fishtailing occurs.
Similar behavior is evident during heavy braking in all types of road vehicles due to weight transfer
Weight transfer and load transfer are two expressions used somewhat confusingly to describe two distinct effects:
*the change in load borne by different wheels of even perfectly rigid vehicles during acceleration
*the change in center of mas ...
to the front. This can be mitigated by re-proportioning the braking forces (more to the front, less to the rear) to keep the rear wheels from locking up.
See also
*Aquaplaning
Aquaplaning or hydroplaning by the tires of a road vehicle, aircraft or other wheeled vehicle occurs when a layer of water builds between the wheels of the vehicle and the road surface, leading to a loss of traction that prevents the vehicle ...
*Black ice
Black ice, sometimes called clear ice, is a coating of glaze ice on a surface, for example on streets or on lakes. The ice itself is not black, but visually transparent, allowing the often black road below to be seen through it and light to be ...
*Doughnut (driving)
A doughnut or donut is a maneuver performed while driving a vehicle. Performing this maneuver entails rotating the rear or front of the vehicle around the opposite set of wheels in a continuous motion, creating (ideally) a circular skid-mark p ...
* Drifting
*Jackknifing
Jackknifing is the folding of an articulated vehicle so that it resembles the acute angle of a folding pocket knife. If a vehicle towing a trailer skids, the trailer can push the towing vehicle from behind until it spins the vehicle around and ...
*Speed wobble
Speed wobble (also known as shimmy, tank-slapper, or death wobble) is a rapid side-to-side shaking of a vehicle's wheel(s) that occurs at high speeds and can lead to loss of control. It presents as a quick (4–10 Hz) oscillation of prim ...
*Hydroplaning
Aquaplaning or hydroplaning by the tires of a road vehicle, aircraft or other wheeled vehicle occurs when a layer of water builds between the wheels of the vehicle and the road surface, leading to a loss of traction (engineering), traction tha ...
References
{{Automotive handling Automotive safety Driving techniques