Trailbraking is not very well understood or practiced, but when used correctly, it allows you to squeeze additional performance out of your car and greatly improves your car control abilities. Trailbraking is when you extend the braking zone into the first part of a turn. Yes, this means that you are both braking and turning at the same time, all at the limit of your car.

Why Trailbrake?
There are two reasons to trailbrake: 1) it can be faster through certain corners and 2) it can help a car turn in and rotate.

The Line as described in The Line, Part 1 describes a constant radius corner. You slow down to your car’s maximum cornering speed before you enter the corner, and then proceed through the corner at neutral throttle until track-out.

But on a track, you want to be on the gas as much as possible. If you brake completely before a corner, then the entirety of your braking zone is on the previous straightaway. Since straightaways are where we can go fastest, the more time we can spend accelerating on them, the faster we will get around the track. In some situations, extending the braking zone into the corner itself extends the amount of time accelerating on the straightaway, and makes us quicker around the track.

Which Corners benefit from Trailbraking?
This is a hard question to answer. The best answer is to simply try regular and trailbraking, and see which technique works better. I have found corners that have a very gradual curve at their start and then tighten up can work well for trailbraking. The corner I am thinking of specifically is The Bowl at NHIS. The best line through this corner takes you around the outer edge of the corner for about 40 feet, at which point you turn in. During this 40 feet, you are turning, but slightly. I have found trailbraking in this corner to be much faster than just riding out those 40 feet at neutral throttle.

Turn In Bite and Rotation
Trailbraking is also a good way to get a car to have more turn in bite and to get the car rotating. As explained in greater depth in Indepth Oversteer, when you brake and turn, your weight shifts forward, giving your turning tires more grip. For cars that consistently understeer and don’t want to turn in, trailbraking can be a good solution to make the car behave better.

Trailbraking and the Friction Circle
If you read The Friction Circle you should be saying to yourself, “I can’t brake at threshold and begin turning or I will exceed my tires’ grip.” You’re right! You cannot. What you can do is brake almost at the limit and begin to turn. When you trailbrake, you transition your braking traction into turning traction.

How to Trailbrake
Remember in The Line: Part 4 [link] where we learned to slowly give more throttle out of a corner while gradually unwinding the wheel? Trailbraking is simply this action in reverse. You begin your braking zone on the straightaway at maximum braking force. When you reach the turn-in point you let off of the brake pedal slowly while simultaneously turning the steering wheel. Sounds simple enough right? In theory, it is. But because you are flirting with the limits of both your braking and cornering grip, your trailbraking takes lots of practice to master.

Dangers of Trailbraking
Of all the techniques used on the racetrack, trailbraking may well be the most dangerous. There are two principle reasons for this: brake oversteer and the consequences of not slowing down enough.

As covered in greater detail in Indepth Oversteer, Brake Oversteer occurs when hitting the brakes while turning shifts enough weight forward that the rear tire lose traction and begin to slip. If not corrected fast, the car will spin out completely. In order to correct Brake Oversteer, you actually need to give the car some gas, which is the exact opposite of what you should be doing in the braking zone.

This brings us to the next major danger of trailbraking: the consequences of not slowing down enough before a corner. The short answer is that if you don’t slow down enough for a corner, your car WILL leave the track. What happens at that point is between you and the lucky rabbit foot you have dangling from you ignition keys. In any other place on the track, the risks of improperly executing a technique are usually just a slower start, and slower track time. Yes your car might leave the track, but it is not as likely or dire as in a braking and turning zone. The difficulty with trailbraking is that you are flirting with the limit of two directions of traction, and pushing one off to the other. Your actions and inputs MUST be flawless, or you can find yourself in serious trouble.

How to Learn Trailbraking
The way to learn trailbraking is to take baby steps. First, master the braking completely on the straightaway, so that you don’t have to brake anymore more after turn-in. This will help you develop a feel for threshold braking in your car, and for applying your braking technique to specific points and zones on the track.

Next, move you braking zone in to the corner a little bit. Start your braking a few feet later, and extend your braking a few feet past the turn-in point. Start doing this SLOWLY, so that most of you speed has already been bled off when you try turning while braking. Consequences will be less dire at lower speeds. Practice synchronizing your braking foot and hands. As you turn your hands, you lift your foot. Practice this until it becomes second nature. At this point, slowly bush the braking zone farther and farther into the corner.

When perfected, you should be able to trailbrake right up to the point when you get on the gas. Coasting will become a thing of the past.