Left-foot braking
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Left-foot braking is the technique of using the left foot to operate the brake pedal in an automobile, leaving the right foot dedicated to the throttle pedal. It contrasts with the normal practice of the left foot operating the clutch pedal, and the right foot operating the brake and accelerator pedals. It is most commonly used in auto racing, but is also used by some drivers for use with an automatic transmission, as the left foot is not needed to operate a clutch pedal. The most significant consequence is that the driver can operate both the accelerator and brake at once, creating the potential for spins, while not allowing the clutch and brake to be used together. Critics say that the practice can be dangerous.
At its most basic purpose, left-foot braking can be used to decrease the time spent between the right foot moving between the brake and throttle pedals. It can also be used to control load transfer.
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[edit] Racing and rallying
Karts, many open wheelers, and some modern road cars (such as the Enzo Ferrari), have no foot-operated clutch, and so allow the driver to use his left foot to brake.
One common race situation that requires left-foot braking is when a racer is cornering under power. If the driver doesn't want to lift off the throttle, and potentially cause a trailing-throttle oversteer situation, left-foot braking can induce a mild oversteer situation, and help the car "tuck," or turn-in better. Mild left-foot braking can also help cure an understeer situation.
In rallying it applies primarily to front-wheel drive vehicles. It is closely related to the handbrake turn, but involves locking the rear wheels using the foot brake, which is set up to apply a significant pressure bias to the rear brakes. The vehicle is balanced using engine power by use of the accelerator pedal, operated by the right foot. The left foot is thus brought into play to operate the brake. Rear-wheel drive rally vehicles do not use this technique because they can be much more easily turned rapidly by using excess power to the wheels and the use of opposite lock steering.
Swedish rally legend Stig Blomqvist is considered to be the inventor of left-foot braking, developing it while driving for the SAAB works team in the 60's and 70's.
This technique should not be confused with Heel-and-Toe, another driving technique.
[edit] Left-foot braking with automatic transmission
Some commentators recommend left-foot braking as routine practise when driving vehicles fitted wth an automatic transmission, particularly when maneuvering at low speeds.[1]
This advice is controversial, and is opposed by others.[citation needed]
Proponents of the technique note that in low-speed manoeuvres, a driver of a vehicle with a manual transmission will usually keep a foot poised over the clutch pedal, ready to disengage power when the vehicle nears an obstacle. This means that disengagement is also possible in the event of malfunction such as an engine surge.
However, the absence of a clutch on a vehicle with automatic transmission means that there is no such safety override, unless the driver has a foot poised over the brake pedal.
Critics of the technique suggest that it can cause confusion when switching to or from a vehicle with a manual transmission. [2]
[edit] Decline of left foot braking
Many modern vehicles use a "Drive By Wire" or Electronic throttle control system instead of the traditional mechanical throttle linkage. These systems do not allow for left foot braking. As the throttle is connected to the car's ECU, it can detect when both pedals are pressed simultaneously and will immediately cut the engine power. This is in case of a malfunction in the throttle body or a stuck pedal. An example is all modern Volkswagen and Audi Group vehicles.
[edit] References
- Speed Secrets: Professional Race Driving Techniques by Ross Bentley - ISBN 0760305188
- Secrets of Solo Racing: Expert Techniques for Autocrossing and Time Trials by Henry A. Watts - ISBN 0962057312
