Opposite lock, also commonly known as counter-steering, is a colloquial term used to mean the steering associated with the deliberate use of

oversteer Understeer and oversteer are vehicle dynamics terms used to describe the sensitivity of a vehicle to steering. Oversteer is what occurs when a car turns (steers) by more than the amount commanded by the driver. Conversely, understeer is what occu ...

to turn a vehicle rapidly without losing

momentum In Newtonian mechanics, momentum (more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If is an object's mass an ...

. It is typified by the classic

rallying Rally is a wide-ranging form of motorsport with various competitive motoring elements such as speed tests (often called ''rally racing),'' navigation tests, or the ability to reach waypoints or a destination at a prescribed time or average speed. ...

style of rear-wheel drive cars, where a

car A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded as ...

travels around a bend with a large drift angle. The terms "opposite lock" and "counter-steering" refer to the position of the steering wheel during the maneuver, which is turned in the opposite direction to that of the bend. The technique works best on loose or wet surfaces where the friction between the tires and the road is not too high, but can also be used on asphalt or other surfaces with high friction if the vehicle has enough power to maintain speed. Before entry to the bend, the car is turned towards the bend slightly, but quickly, so as to cause a rotating motion that induces the rear of the car to slide outwards. Power is applied which applies further sideways movement. At the same time, opposite lock steering is applied to keep the car on the desired course. As the car reaches the bend it will have already turned through most of the needed angle, traveling sideways and losing some speed as a result. A smooth application of power at this point will accelerate the car into the bend and then through it, gradually removing the sideways component of travel. For front-wheel drive vehicles, there is much less natural tendency for the rear wheels to break traction because they are not transmitting power, so often such vehicles are set up with a strong bias to the rear brakes, allowing the driver to control traction using the brake pedal. The

brake balance The brake balance or brake bias of a vehicle is the distribution of brake force at the front and rear tires, and may be given as the percentage distributed to the front brakes (e.g. 52%) or as the ratio of front and rear percentages (e.g. 52/48). Th ...

(front/rear braking force) may be continually controllable by the driver using a hand lever.

Left-foot braking 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 practice of using the left foot to operate the clutch pedal, leavi ...

is the favoured technique for using opposite lock in a front drive vehicle. Opposite lock can be a useful technique for saving a car from a loss of control such as an unintentional skid. A related technique is the

handbrake turn The handbrake turn (also known as the bootlegger's turn) is a driving technique used to deliberately slide a car sideways, either for the purpose of quickly negotiating a very tight bend, or for turning around well within the vehicle's own turning ...

, in which the rear wheels are deliberately locked in order to break the friction between the tires and the road, allowing the car to be spun around a very tight bend or junction, etc.

References

{{Reflist Driving techniques

See also

References