Handbrake turn
Encyclopedia
The handbrake turn is a driving technique used to deliberately slide a car sideways, either for the purpose of negotiating a very tight bend quickly, or for turning around well within the vehicle's own turning circle.

The driver starts by using steering input to transfer weight to the outside tires; the handbrake
Hand brake
In cars, the hand brake is a latching brake usually used to keep the car stationary, and in manual transmission vehicles, as an aid to starting the vehicle from stopped when going up an incline - with one foot on the clutch , the other on the accelerator In cars, the hand brake (emergency brake,...

 is then used to lock the rear wheels, thus upsetting the adhesion between the tires and the road surface. With practice, the car can be placed accurately by releasing the handbrake and accelerating the vehicle. The technique is used in some forms of motorsport
Auto racing
Auto racing is a motorsport involving the racing of cars for competition. It is one of the world's most watched televised sports.-The beginning of racing:...

, for example rallying
Rallying
Rallying, also known as rally racing, is a form of auto racing that takes place on public or private roads with modified production or specially built road-legal cars...

, autotesting
Autotesting
Autotesting involves a series of tests, generally around traffic cones, to measure precision driving skill. The tests often include stopping with the front and rear wheels straddling a line, and always end stopping in a garage . Sections of each test are usually completed in reverse...

, and motorkhana
Motorkhana
Motorkhana is a low-cost form of motorsport, unique to Australia and New Zealand but similar to autotesting in the UK and Ireland and somewhat similar to autocross in the US. It involves manoeuvring a car through tight tests as quickly as possible - one car at a time - on either dirt or bitumen...

.

Many sports cars, especially English makes such as MG and Triumph, as late as the early 1970s were offered with a fly-off handbrake option for competition purposes—the button on the end of the lever has to be pressed before the brake will lock on, which is the reverse of the normal arrangement—allowing for faster and more controlled application in a handbrake turn, and was less liable to be accidentally locked on while doing such a maneuver.

In a rear-wheel drive manual transmission
Manual transmission
A manual transmission, also known as a manual gearbox or standard transmission is a type of transmission used in motor vehicle applications...

 vehicle, it is also necessary to operate the clutch
Clutch
A clutch is a mechanical device which provides for the transmission of power from one component to another...

 to prevent the handbrake from stalling the engine.

Physics involved

In a normal turn, the rear wheels follow the front ones because the resistance in the forward direction (i.e. where the wheels turn) is significantly less than in the sideways direction, and the latter provides the centripetal force
Centripetal force
Centripetal force is a force that makes a body follow a curved path: it is always directed orthogonal to the velocity of the body, toward the instantaneous center of curvature of the path. The mathematical description was derived in 1659 by Dutch physicist Christiaan Huygens...

 that makes the rear end follow the turn. When the driver locks the rear wheels with the handbrake, both directions have the same resistance, so the rear end tends to keep moving in the original direction (inertia) and thus it slides out.

Usage

Handbrake turns are primarily a technique used to negotiate tight turns in motorsport
Motorsport
Motorsport or motorsports is the group of sports which primarily involve the use of motorized vehicles, whether for racing or non-racing competition...

 but can also be used in certain other applications such as stunt or pursuit driving.

For stunt
Stunt
A stunt is an unusual and difficult physical feat, or any act requiring a special skill, performed for artistic purposes in TV, theatre, or cinema...

 purposes, parallel parking
Parallel parking
thumb|250px|right|Parallel-parked cars in [[Washington, D.C.]]thumb|250px|right|A motorist gets assistance parallel-parkingParallel parking is a method of parking a vehicle in line with other parked cars. Cars parked in parallel are in one line, parallel to the curb, with the front bumper of each...

 can be completed in a single motion using the handbrake. This technique is often demonstrated at car shows, demonstrating the vehicle's agility and the driver's control.

In pursuit driving, the technique can be used for turning the car around in the width of two lanes without using a three-point maneuver (see bootleg turn
Bootleg turn
A bootleg turn is a radical driving maneuver intended to reverse the direction of travel of a forward-moving automobile by 180 degrees in a minimum amount of time while staying within the width of a two-lane road...

), for example to bewilder a pursuer. It can also be used to quickly negotiate tight corners.

Usage in drifting

Whereas pulling the handbrake is the easiest way to start a drift, it's rarely used in racing, because it causes significant loss of speed at the exit of the corner. Racers use handbrake turning only to negotiate tight 180 degrees bends that would otherwise require a three-point maneuver to go through.

In UK and Europe, many cars are front wheel drive. For rallying, cars are often fitted with a "hydraulic handbrake", in this case, a secondary master cylinder is connected to only the rear brakes. By using a hydraulic, rather than the conventional cable handbrake, the rear brakes can be locked up instantaneously and repeatedly. Many rally drivers will use the handbrake to correct the inherent understeer in a front wheel drive car, while maintaining full forward speed. This as opposed, to "lift off oversteer", induced to the chassis through lifting the throttle pedal sharply mid corner to encourage weight transfer, at the cost of exit speed from a corner.

Dangers

Like other methods of inducing a drift, the handbrake turn does pose a serious risk of the vehicle flipping over, and caution must be taken when performing the maneuver with a vehicle with a high center of gravity (like an SUV). The basic danger lies in bad judgment of surroundings, resulting in the sliding vehicle hitting an obstacle (another vehicle, a guardrail or a tree), or bad judgment of speed, resulting in the vehicle driving off the road rather than sliding, or releasing the handbrake when the vehicle is moving sideways so that all tire forces are sideways.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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