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MotorCulture
16-05-12, 12:10 PM
As an owner of a performance car it’s safe to say that attending a track day is inevitable. Modding begins and parts like brakes, brake pads and tyres are usually the first to get upgraded in pursuit of achieving a personal best lap time and then you also have good old race craft, that doesn’t cost anything but practice, practice, practice.

What is Trail Braking?

Trail-Braking is a technique used by rally drivers to negotiate single corners at high speeds. Typically, the average driver negotiates a corner by first braking to regulate the speed, then releasing the brakes and steering the vehicle along the corner, and finally accelerating after the exit of the corner. Trail-Braking is used when the approach speed to the corner is high and the braking must continue even after the steering of the vehicle has started.

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Consider for example a 90 deg left corner as in Fig. 1. Approaching the corner at high speed from the outer edge of the road, Trail-Braking begins by braking the vehicle without steering. The driver adjusts the brake pressure such that the maximum available friction is generated by the tire. This means that the maximum available deceleration is generated; subsequently, no friction is available for steering. As the vehicle approaches the corner, the driver starts steering. In Trail-Braking this is done by progressively releasing the brake (in order to allow cornering forces at the tires) and simultaneously–and progressively–increasing the steering angle. As the vehicle decelerates, the weight of the vehicle transfers from the rear to the front axle and thus, the front tires generate higher friction than the rear ones. The vehicle rotates about the vertical axis, counterclockwise. As the vehicle reaches the apex of the corner and its attitude is aligned with the exit of the corner, the driver accelerates and counter-steers (steers towards the opposite side of the corner) to stop the rotation of the vehicle and start the acceleration towards the exit of the corner. Acceleration causes weight transfer from the front axle to the rear. As a result, the rear tires generate more friction, resisting the counterclockwise rotation of the vehicle. Overall, TB involves high vehicle slip angles and yaw rates. This allows the vehicle to reach a controllable, straight line driving state as quickly as possible, and allow the driver to react to unexpected road condition changes ahead of the corner, which are typical in off-road rally racing.

Source : http://soliton.ae.gatech.edu/people/ptsiotra/Papers/ecc07a.pdf

SO, who has tried it? How hard was it to learn? And how effective did you find it?