Most of the lap time in ACC is in the braking zones. Not on the straights, where the car does the work, and not in the fast corners, where everyone is flat or close to it. It is in the 100 metres before each slow corner.
The good news is that braking is a skill you can train on purpose. Here is how I would do it.
The shape of a good braking zone
Every braking zone has the same shape. Hard at the start, then a long release.
Hit it hard. At the end of a straight the car is at its fastest, so the wings are making the most downforce and the tyres have the most grip. That is the moment to use all the brake. Go to full pressure at once.
Think about a real road. If someone steps out in front of your car, you do not squeeze the pedal politely. You stamp on it and hold it. You already know how to brake at 100%. Most drivers never do it on track.
Release as the car slows. The downforce drops with the speed, and the grip goes with it. If you keep full pressure, the fronts lock or the ABS takes over. So you come off the pedal gradually as the speed falls.
Keep some on into the corner. You turn in with the brake still on, and you bleed off the last of it on the way to the apex. That last part is trail braking.
What trail braking is for
People say trail braking is about rotation. It does help: brake pressure keeps weight on the front tyres, so the nose bites and the car turns.
But for me the bigger reason is simpler. If you have to be fully off the brake before you turn, you have to start braking earlier. If you can carry the brake into the corner, your braking point moves later. That is free lap time on every lap.
A lot of people teach slow in, fast out. I do not like it. The goal is fast in and fast out: brake as late as you can, still make the apex, and still get a clean exit. Trail braking is what makes the first part possible.
How much to trail, corner by corner
| Corner type | How I would brake | Why |
|---|---|---|
| Slow hairpin or chicane | Trail the brake almost to the apex | The car needs the front loaded to rotate at low speed |
| Medium speed corner | Off the brake well before the apex, already picking up the throttle | Too much brake here kills the minimum speed |
| Fast corner | A short brake or a lift, in a straight line, then commit | The aero is doing the work. Keep the car settled |
| Downhill braking zone | Brake earlier and release more gently | The rear is light and wants to come round |
| Braking while turning | Less peak pressure, long and smooth | The tyre is already busy with the corner |
My rule of thumb, and it holds in every kind of car: in a slow corner, trail the brake until it feels like you are braking to the apex. In a medium speed corner, be off the brake well before the apex and already on the throttle.
And do not coast. If you are off the brake and not yet on the throttle, the car is doing nothing useful. Either you braked too early or you are waiting too long to go.
You cannot learn it from a number
I cannot tell you to release the brake at 73 metres or after 1.3 seconds. Nobody can. The release happens in a fraction of a second and you do it by feel.
It builds on its own when you push the braking point. Brake a little later, and the only way to still make the corner is to hold the brake longer into it. Do that for a week and you are trail braking without thinking about it.
So the drill is simple:
- Pick one slow corner and one braking marker.
- Do ten laps at that marker until the apex is easy.
- Move the brake point two or three metres later.
- When you start missing the apex, go back one step. That is your point for today.
Use the delta on the HUD to see if it worked. More on that in the ACC HUD guide.
ABS in ACC
GT3 and GT4 cars have ABS, so you can hit the pedal harder than in a formula car without a huge lock up. That makes the first hit easy. It does not do the release for you.
If the ABS is working all the way from the brake point to the apex, you are overbraking. The car is not slowing any faster, the front tyres are heating up, and the nose will not turn. Use the ABS as a safety net for the first part of the zone, then get under it as you release.
A lower ABS number gives you more stopping power and less help. A higher one is safer and a bit longer. In the rain, go up two or three clicks. The wet side is in the ACC wet weather guide.
The settings that change the braking
| Setting | What it changes | Where I would start |
|---|---|---|
| ABS | How early the system steps in when a wheel is about to lock | The value in the aggressive preset. One click lower if the car will not stop, one higher if the fronts lock |
| Brake bias | How much of the braking goes to the front | The preset value. Move it 0.5% at a time |
| Brake ducts | Brake temperature, and through the wheel the tyre pressure | Whatever keeps the fronts at 600 to 650 C and the rears near 450 C |
| Brake pads | Bite, wear and how they behave cold | Pad 1 for sprints, pad 2 for long races, a softer bite in the wet |
| Brake gamma, in the controls | How the pedal travel maps to pressure | Leave it linear with a load cell. Raise it a little with a soft pedal |
Brake bias is the one to learn to change while you drive. Forward makes the car stable on the brakes but lazy to turn. Rearward helps it rotate but the rear gets nervous. As the fuel burns off and the tyres wear, a small move through the race keeps the balance.
If the car is unstable on entry and no bias setting fixes it, the problem is in the setup, not in your foot. Start with the ACC setup guide and the page on understeer and oversteer.
Downshifts
Shift down as the revs fall, not all at once at the brake point. ACC will refuse a downshift that would over rev the engine, so banging the paddle three times early does nothing useful.
A downshift also adds engine braking at the rear. Do it too early in a rear or mid engined car and the back steps out. If the rear moves every time you shift, wait a moment longer for each gear.
Pedals
You brake with pressure, not with travel. That is why a load cell pedal helps so much: your leg remembers force far better than position.
With a soft pedal like the one on a Logitech set you can still be quick. It just takes more laps to be consistent, and the release is harder to feel.
Fixing common problems
| What happens | Likely cause | Fix |
|---|---|---|
| You miss the apex and run wide | Braking too late, or off the brake too early so the front goes light | Brake at the same point but hold a little brake into the corner |
| The rear steps out on entry | Too much brake still on while turning, bias too far back, or a downshift too early | Release sooner, move the bias 0.5% forward, shift a moment later |
| The car will not stop | Soft first hit, ABS too high, or cold or cooked brakes | Hit the pedal harder at the start, check ABS and brake temperatures |
| Slow in the middle of the corner | You braked early, came off and coasted | Brake later and keep trailing. Coasting is lost time |
| Good for five laps, then worse | Front tyres or brakes overheating | Open the ducts a step and stop leaning on the ABS |
FAQ
What is trail braking in ACC?
Keeping some brake pressure on after you turn in and releasing it gradually on the way to the apex. It keeps weight on the front tyres and lets you brake later.
How hard should I brake in ACC?
Full pressure at the start of the zone, when the car is fastest and has the most downforce. Then release as the speed comes down.
What ABS setting should I use in ACC?
Start from the value in the aggressive preset. Go one click lower if the car will not stop, and two or three higher in the rain.
What brake bias should I run in ACC?
Start from the preset and move it 0.5% at a time. Forward for stability, rearward for rotation.
Why does my car spin when I brake in ACC?
Too much brake while turning, a bias that is too far back, or a downshift that came too early. Release sooner and shift a moment later.
Should I brake until the apex?
In slow corners, almost. In medium speed corners, be off the brake well before the apex and already picking up the throttle.
Do I need a load cell brake for ACC?
No, but it helps. A load cell measures pressure, which is easier to repeat than pedal travel.