Double-Apex Corners Explained: How to Choose Your Racing Line

Most explanations of a double apex stop at the diagram: two clipping points, one corner, hit them both. That tells you what the corner is and nothing about the decision it actually asks of you, which is how wide to let the car run in the middle — and that decision has a real answer, with two inputs, that changes from car to car and corner to corner.

This guide is the version from our Foundations course, where the coach draws the lines on the corner and then rejects two of them. It covers what a double apex is, why it is one corner rather than two, the long trail brake it needs, and the rule for choosing between a tight line and a wide one.

What is a double-apex corner?

A double-apex corner is a corner with two parts, close enough together that the exit of the first is the entry of the second. You touch the inside twice, with a section in between where the car runs a little wider.

The definition matters less than the framing that comes with it: "it's almost like you're having two different corners, but because they're so intertwined, it's wrong to talk about each of them separately — so we need to treat them as a whole."

Two apexes, one corner. That is the sentence to keep, and everything below is a consequence of it.

Corner geometry versus a double-apex line

Worth separating two things that get conflated, because it decides whether this page applies to a corner you are struggling with.

Double-apex geometry is a property of the circuit: the road genuinely has two tightenings with a brief release between them. You do not choose this; it is there.

A double-apex line is a driving choice, and you can take one through a corner that is not shaped that way — most often a long constant-radius corner, where touching the inside twice with a small release between lets you straighten both halves rather than holding one compromise radius all the way round.

This page is mostly about the first, because that is where the decision is forced. But the reasoning transfers: in both cases you are trading distance travelled against how early you can accelerate, and that trade is the whole subject.

One sweeping motion: why the inputs stay continuous

If a double apex is one corner, the inputs should look like one corner's inputs.

The test is what your pedal trace does through the middle. Driving it as two corners produces a distinctive signature — brake, throttle, brake again, throttle again — and every one of those transitions costs you time and stability. Driving it as one produces a single continuous shape: "we stay on the brakes, we trail brake, and then we go on throttle, and that's it."

The coach's word for it is a sweeping motion, and it is the diagnostic to run first on any double apex that feels awkward. If there are two throttle applications and two brake applications in the middle of a corner you are calling one corner, you are not yet driving it as one.

The long trail brake a double apex needs

Because a double apex is a long corner with a second commitment point inside it, the brake release is stretched far longer than in an ordinary corner. You brake harder initially, then trail the pressure well past the first apex — a long, shallow tail rather than a quick release.

The contrast the lesson draws is with a short, sharp brake shape, and the explanation of why it fails is the most useful mechanical point on this page: "if you're going to brake for a short time, it means you will go on throttle earlier" — and once you are on the throttle, the car starts running wide, "so you're getting the first apex, you're getting on throttle earlier, but you're completely missing the second one, and then the car gets wider and you lose a lot of time."

That is the single most common double-apex failure, and notice that it does not feel like a mistake while you are making it. Hitting the first apex and getting to power early feels like a corner going well. The cost arrives half a second later when the car is out of road with a second apex still to come, and by then the only options are a lift or a correction — both of which cost more than the early throttle gained.

So: the brake is what buys you the second apex. Holding it longer keeps the front loaded and the car rotating, which keeps the nose tight enough to reach the second clipping point. If your instinct is that you are braking oddly late into the middle of the corner, that instinct is what a correctly driven double apex feels like. The general technique is trail braking; a double apex is simply the corner that asks for the most of it.

Hitting both apexes properly

The first building block is unglamorous: get genuinely close to the inside at both points.

"You need to hit it dead on… it's important to hit it as close as you can to the most inside part of the corner." Missing an apex by half a metre at each of two points compounds — you are now driving a wider, longer corner than the one that exists, and every metre of extra width has to be paid for with a later throttle application.

This is also where the corner punishes vision. The second apex is frequently not visible when you need to be committing to it — in the drill it is hidden behind the A-pillar, and the instruction is to see it "with your mind's eye" and use the moment the kerb appears as the throttle cue. Building a checkpoint chain for a corner you cannot fully see is covered in how to learn a track.

How wide should you run between the apexes?

Here is the real decision, and the part most explanations skip.

You have to run a little wide between the two apexes — that is what makes them two apexes rather than one long scrape along the inside. The question is how much, and there are two candidate shapes:

A U-shaped line stays tighter through the middle, travels less distance, and gets to the second apex with less lateral movement. A V-shaped line lets the car run out further between the apexes, travels more distance, and straightens each half more — which means it can get to the throttle earlier.

Two inputs decide it.

Input one: what car are you in?

A downforce car wants the tighter, U-shaped line. It has the aerodynamic grip to hold a tighter radius at speed without losing time for it, so the extra distance of a wide line buys it very little. A GT car — less downforce, more dependent on being straight to use its power — generally prefers the wider, V-shaped line.

The lesson states it plainly: "if you have a formula car, keep a U-shaped line, don't go very very wide; but if you have a GT car, generally this V-shaped line will work a tiny bit better."

Input two: how long is the straight afterwards?

This is the input nobody mentions, and it can override the first.

The advantage of the wider line is an earlier throttle point. The cost is extra distance — "we're travelling a longer distance… all this extra distance that we're covering to be able to go earlier on throttle." Whether that trade pays depends entirely on how much road you have afterwards to convert the earlier throttle into speed.

So the rule is: "we choose the line, V-shaped or U-shaped, based on the car type — formula or GT — plus we ask ourselves how long is the straight after the double-apex corner. If it's a very long straight, then we will push the car wider. But if the next straight is very short, like we have another corner nearby, then it's not worth it to cover more distance."

That is an actual decision procedure, and it is why in the drill a GT car is deliberately not driven on the widest available line: the exit there leads to a short section, so the extra distance would never be repaid.

Both extremes are wrong

Two lines get drawn and then rejected. The very wide one covers distance it cannot recoup. The very tight one looks efficient — it is the shortest path — and it is the worse of the two, for a reason worth stating: "you will always wait until you put a throttle down… you will be stuck near this inside part of the long corner, and you don't want that." A car pinned to the inside is still turning, and a car still turning cannot accelerate. "The further away you get from the red line, the earlier you will go on throttle."

Which gives the useful mental frame: you are not choosing between "tight" and "wide", you are choosing a point on a scale between two known-bad extremes, using car type and the length of the next straight to place it.

Mistakes that add distance or a second slowdown

1. Releasing the brake too early. The big one. Early throttle, first apex hit, second apex missed, car wide, and a corrective lift that costs more than the early throttle gained.
2. Driving it as two corners. Brake, throttle, brake, throttle. Two slowdowns where the corner only justifies one.
3. Missing the apexes by a small margin at both points. Cheap to fix, and it silently widens the whole corner.
4. Choosing the line by feel rather than by what follows. The wide line feels fast because the throttle comes early. If the following straight is short, that feeling is costing you.
5. Being too tight because it looks efficient. The shortest path is not the fastest when it traps you on the inside with the wheel still turned.

The double-apex drill

The course drill uses a BMW M2 at Laguna Seca's opening complex, with an active reset before the corner. Braking around 60–70 per cent, using the full width on entry, turning in early for the first apex in third gear, close to the sausage kerb — and still braking.

The cue for the throttle is visual: the second kerb is hidden by the A-pillar, and when its blue section appears, you should already be going to power, so that the second apex is taken at or near full throttle.

Common double-apex questions

Is a double-apex corner the same as two separate corners?

No, and treating it as two is the most expensive framing error you can make here. The two halves are close enough that the exit of the first is the entry of the second, so the inputs should stay continuous — one brake application, one release, one throttle application. Two brake applications inside one corner is a symptom, not a style.

How wide should I go between the apexes?

Wide enough to straighten both halves, not so wide that you spend distance you cannot recoup. Start from the car — tighter for a downforce car, wider for a GT — then adjust for the length of the straight after the corner: long straight, run wider; short link into another corner, keep it tight. Both extremes are slower than anything in the middle.

Why does hitting both apexes still leave me slow?

Usually the brake. If you released early and got to the throttle before the middle section, you will reach both apexes but arrive at the second one already running wide, with the exit compromised. Hitting the apexes is necessary and not sufficient — what matters is the state the car is in when it gets there.

Does a formula car really want a different line from a GT?

Yes, and the reason is grip rather than preference. A downforce car can hold a tighter radius at speed without paying much for it, so it gains little from the extra distance of a wide line. A GT depends more on being straight to deploy power, so straightening each half earns more. It is a small difference in shape with a real difference in lap time, and it is worth testing rather than assuming — which is what the drill is for.

If the corner still costs you time after the drill and you cannot see where, that is a telemetry question rather than a technique one, and the telemetry guide covers how to read a long corner properly. The full lesson and drill, and every other corner type, are in the Foundations course.

Double-apex FAQ

What is a double-apex corner?

A corner with two tightenings and a brief release between them, so the car touches the inside twice. The important part is that the two halves are intertwined enough that they cannot be driven separately — the exit of the first is the entry of the second, so it is one corner with two clipping points rather than two corners in a row. What a double apex is.

Is a double-apex corner the same as two separate corners?

No, and treating it as two is the most expensive mistake available here. The inputs should stay continuous — one brake application, one long release, one throttle application. Two brake applications and two throttle applications inside a single corner is a symptom that you are driving it as two, and each extra transition costs time and stability. One sweeping motion.

How wide should I run between the two apexes?

Wide enough to straighten both halves, not so wide that you cover distance you cannot recoup. Start from the car — a downforce car wants a tighter, U-shaped line, a GT car a wider, V-shaped one — then adjust for the straight that follows: long straight, run wider; a short link into another corner, keep it tight. Both extremes are slower than anything in the middle. How wide to run.

Why does touching both apexes still leave me slow?

Usually the brake. If you released it early and got to the throttle before the middle section, you will still reach both apexes but arrive at the second one already running wide, with the exit compromised and a corrective lift to come. Hitting the apexes is necessary and not sufficient — what matters is the state the car is in when it gets there. The long trail brake.

Why do double apexes need such a long trail brake?

Because the brake is what buys you the second apex. Holding pressure well past the first apex keeps the front loaded and the car rotating, which keeps the nose tight enough to reach the second clipping point. Release early and you get to the throttle sooner, the car runs wide, and the second apex is gone. If it feels like you are braking oddly deep into the middle of the corner, that is what a correctly driven double apex feels like. The brake shape.

Do formula and GT cars want different lines through a double apex?

Yes, and the reason is grip rather than taste. A downforce car can hold a tighter radius at speed without paying much for it, so the extra distance of a wide line buys it little. A GT depends more on being straight to deploy its power, so straightening each half earns more. It is a small difference in shape with a real difference in lap time. Car type and line.

Why is the tightest line through a double apex not the fastest?

Because a car pinned to the inside is still turning, and a car still turning cannot accelerate. The shortest path traps you against the inside of a long corner and delays the throttle until the road finally opens — and the further you get from that extreme, the earlier the throttle comes. It is the shortest distance and usually the slowest section. Why both extremes lose.

What is the difference between a double-apex corner and a double-apex line?

The corner is a property of the circuit: the road genuinely has two tightenings. The line is a choice you can make through a corner that is not shaped that way — most often a long constant-radius corner, where touching the inside twice with a small release between straightens both halves instead of holding one compromise radius throughout. The trade is the same either way: distance travelled against how early you can accelerate. Geometry versus line.