Master the art of trail braking
Driving fast is never as easy as it seems and requires a number of different parts to work in harmony. There are a variety of techniques used by drivers – both in real life and in sim racing – that help them achieve faster lap times and better results.
At Traxion, our goal is to give you as much information as possible about racing techniques, helping you become a better rider. Therefore, I’m going to tell you about a pretty advanced braking technique that just might help you bridge the gap between fast and very fast lap times. This technique is called trail braking.
The usual braking advice is to brake hard in a straight line towards a bend, releasing the brakes before turning. While this is good advice when learning the ropes, it’s not always the best way to take a corner.
I’ll explain exactly why trail braking is such an important skill to master if you want to take the next step, then show you how and when to use it.
The best place to start is to contextualize the term to understand what it means. The word “trail” in this case refers to the verb “trailing” which could also be described as “dragging”. Think of it this way, if someone said “I had to pull my partner away from their simulation rig tonight, that infers there was some resistance, but they were dragged in anyway .
It’s kind of like trail braking. You drag the car around a bend using the steering angle, while maintaining some resistance via the brake pedal.
As said before, you’re normally told to brake in a straight line and then turn – and there’s a good reason for that. There is of course a limit to the grip a tire can give you before it starts to slip, and with racing cars that grip has to be shared between lateral (cornering) and longitudinal forces. (i.e. acceleration and deceleration).
The more you turn the steering wheel, the less grip you have available to accelerate or decelerate (and vice versa).
In early January, we did an experiment to see what driving a front wheel drive Formula 1 car. The video perfectly illustrates this theory. Because the front tires were trying to do two things at once—in this case, accelerate and spin at the same time—they struggled to cope.
If I applied no throttle and turned the steering wheel, the car spun smoothly, and similarly if I accelerated without applying steering lock, the car accelerated. But as soon as I tried to do both things at once, the tires couldn’t cope and all grip was lost. I had to really balance the car and only use a little bit of throttle when steering to avoid overworking the tyres.
By focusing on one thing at a time, braking first then steering, you’re only asking the tires to deal with heavy force at a time, giving you decent levels of grip in both stages. And that’s why the smooth braking technique works, it’s safe and keeps you within the available grip.
However, by doing this you are not exploiting the full potential of the tyre, and if you are looking to go as fast as possible you need to maximize every opportunity where extra grip is available. And that’s where trail braking comes in.
This technique allows more use to be made of the grip potential of the tires during the braking and corner entry phases. When you start to turn into a bend, instead of quickly jumping off the brake pedal and turning the steering wheel, hold some pressure on the brakes as you start to turn.
Then, as you have to apply more and more steering input, slowly release your foot from the brake pedal to avoid putting too much stress on the tires. By doing so, you are able to make more use of the available grip heading into the corner, allowing you to carry more speed and therefore save lap time.
However, if you try to use too much steering angle with too much brake pressure applied, you will have the same problem I experienced in the front wheel drive Formula 1 car. The tires will not be able to support lateral cornering loads and longitudinal deceleration loads.
Essentially, this whole process is one big balancing act: it’s about balancing the use of tire grip between cornering and deceleration, and it’s also about balancing the car from the front to back. This is another crucial aspect of trail braking and probably a little easier to understand.
Brake it for me gently
When braking in a bend, a car’s balance changes as weight shifts over the front wheels and away from the rear of the car. This can be useful when heading into a corner because having more weight on the front of the car means your front tires will have more grip, so the car will corner better.
Basically, in this context, think of weight and grip as the same thing. By applying a little brake pressure as you turn into the corner, you can influence the weight transfer from one end of the car to the other. Because of this, you can control the car’s weight distribution back and forth, using your foot. It’s a skill you don’t want to waste.
Imagine you are heading into a long corner at medium speed. Take the example of the Alboreto curve in Monza – formerly known as Parabolica. When you initially hit the brakes in a straight line, you are using a lot of force on the pedal to slow down as quickly as possible.
At this time, all the weight is pushed to the front of the car. If you suddenly release the brakes, the weight shifts rearward and this change can unbalance the car. It also means that the front of the car will have less grip because there is less weight, and the rear of the car will have more grip because there is more weight.
This will often cause natural understeer because the front tires can’t give you the grip you need to turn into the corner. This means you run wide, miss the top and Formula 1 team Scuderia Ferrari will withdraw their contract offer.
Now let’s go back to the initial braking zone and look at the other end of the scale.
This time you brake later and apply too much brake pressure when you start turning into the corner. The front tires aren’t able to cope with the combination of hard braking and hard cornering at this speed, so experience lockup.
Ideally when cornering you want to have enough weight on the front of the car to give you plenty of grip to get you to your top, but not too much to overload the front tires and lock you out. As stated earlier, the brake pedal can be used effectively to control weight transfer and give you the perfect balance in a turn.
All this of course depends on the type of car and the configuration. Front-wheel-drive cars will react differently to rear-wheel-drive cars, brake bias can also be an influence, as can the grip available on the track.
For example a high downforce F1 car with slick tires on a dry track will have a totally different grip threshold than a hot hatch on road tires in the rain, despite what most youngsters men in Britain seem to think…
Curb the Habit
So the next question is how do you know when to brake in drag? Generally speaking, it’s a more advantageous technique to use in slow to medium speed turns, but it’s also handy for some longer turns.
Let’s take the example of the Assetto Corsa Competizione circuits. Some of the best examples of on-track self-braking corners are turns two and five at the Hungaroring, Brooklands and Luffield at Silverstone, and the aforementioned Alboreto curve at Monza.
All these turns are long and at medium or low speed. However, arguably the most important time to use this technique is when approaching a section where one corner acts as a braking zone for the next. The first two corners at Suzuka or Curva Tramonto at Misano are good examples.
You can save so much time here with good trail braking that you can maintain decent speed in the first corner while still maintaining good enough balance to line the ideal line for the next corner.
The best track to practice this technique is undoubtedly Snetterton, in particular the 200 layout if the SIM card you have chosen has it. Turn two – the Montreal hairpin – requires a bit of on-track braking to spin the car to the top. Then turns four and five – Brundle and Nelson – can be taken at much higher speed with good technique.
If you get off balance, you’ll either understeer right or oversteer and veer left. The final section, turns seven and eight – Coram and Murrays – also require a bit of on-track braking, slowing the car as late as possible through Coram while maintaining the optimum racing line towards Murrays to maximize your exit speed.
So, although the 200 layout is a short track, there are three tricky sections to practice your on-track braking technique.
However, not all cars and setups will fit, or even require track braking. Oversteer front wheel drive cars are already very forward biased so might not be able to cope with the added brake pressure, while an understeer rear wheel drive car may require a brake of harder and harder track in the turn in order to get the required rotation at the top.
Alright, I think it’s time to wrap up all this information. Track braking involves maintaining a little brake pressure as you turn around a bend, adjusting the brake pressure as the steering angle increases in order to control the balance of the car.
This not only gives you more control over the front-to-rear balance, but also allows you to use all of your tires’ available grip at all times.
Trail braking is most useful in slower, longer corners and when it works the benefits can be seen in every phase of a corner.
First, you can brake later and carry more speed on corner entry as you maximize available tire grip. Second, being able to control the balance of the car means that you avoid possible wheel spin or understeer by modulating brake pressure as you turn.
Finally, it also allows you to pivot the car better in order to reach your apex, and in turn allows you to rev up sooner and harder on the exit of the corner, increasing your terminal speed in the following straight. .