Understanding the Double Apex

The most basic definition of a double apex is a corner where you touch the inside, then you go a little bit wide, and then you touch the inside on a second moment before you exit that corner. A double apex can be a very obvious one if the corners are quite square and then the line already kind of throws you to the middle and then you can just get back to the second corner because there are two separate corners there are very close to each other. Or it's just one consistent corner that is so long and so big radius that the faster line, because of the closing spiral behavior of a car that's accelerating, becomes one where you touch the inside and you let the car run off and then you touch the inside again.

Of course the second one is less obvious and that's where most people make the most mistakes of getting stuck on the inside, over slowing into the corner, and just losing a lot of time. The magic of double apexing long corners like that is that there's a double benefit. There's a benefit of breaking later and carrying more speed on entry and accelerating more aggressively and having a better line to carry more speed on the exit.

Why Single Apex Doesn't Work in Long Corners

If you try to take a single apex approach in a corner like this, for example, you have to turn in a little bit later. And then by the time you start turning in you realize that the car is at some point here going to be under the limit because the corner is so consistent that if you're turning from here and you're planning to take this line, the speed of the car will decrease and the car is actually going to be able to do more rotation than necessary.

Remember the closing spiral. In order to stay on the limit what you want to do is actually carry more speed. So you carry more speed, but let's say that we start turning in the same place. If you carry more speed and you turn in the same place, then you will miss the corner a little bit too much. And then here you're gonna be a little bit too slow too early and you will want to accelerate. By the time you accelerate, you hit the inside too early and it just doesn't work if you use the same turning point.

The Double Apex Approach

In a double apex approach, what we want to do is turn in earlier. So instead of touching the inside here, we're gonna turn in way earlier like this. Then let's say we touch the apex right here. Now at this point in time, comparing these two lines, the outside line that is a single apex approach and the inside line, the inside line you're carrying a lot more speed.

The Secret to Double Apex Success

Because you're carrying more speed, and here's a secret - don't ignore this - the car will want to go wider because you are faster. The car is not capable of sticking to the inside here so it will run off on its own. You have no choice. If the speed is right, the car is gonna take itself wide after you hit the first apex. And then when you point back, you start accelerating.

And here's the second benefit: when you start accelerating, the line that you can take here is much straighter and you can carry a lot more speed if your car is placed here compared to being placed here. So you see, you gain time on entry because you're carrying a lot more speed here. You're carrying more speed on this inside line. But then because of this extra speed, the inertia will take you wide. But that's fine because you have the space to do it - a corner is long. And then by the time you get here, you already gain speed, but your car is a little bit wider which allows you to do a wider arc here. And then by the time you get back on power, you can do it more aggressively and you can carry a lot more speed.

So you gain time here and you gain time here. This is why we double apex in long corners because the nature of the line when the car's on the limit will be elliptical, will not be circular.

How Downforce Affects Double Apex Technique

Now here's what you really need to know about double apex depending on how much downforce the car has.

Low Downforce Configuration

This is what would look like in a very low downforce car like a Porsche Cup or a GT car with low downforce settings. What happens is the car is not able to rotate at the higher speeds yet, so it needs to turn in very early. And then in low downforce, we hit the apex is pretty early. So the first apex is very early. We carry a lot of speed. We're still accelerating, we're still accelerating, and then the car wants to go wide. Again, the natural behavior of the car is to go wide all the way here. Then we get back on power right here. And then the second time we hit the apex is actually very late. So in a low downforce scenario, the distance between the two apexes is very big.

High Downforce Configuration

Now in a different scenario where the car has a little bit more downforce, here's what happens. Let's add downforce very slowly. So as you can see, the V-shaped line is becoming a more U-shaped line because now in this configuration here the car is able to rotate a lot more on higher speeds on entry.

This is the extreme scenario of like a Formula One car that has a lot of turning capability on the entry already. So the turning point actually moved forward a lot. Again compare the turning point here to the turning point of a Formula car. So this is the turning point of a high downforce car right here, and this is the turning point of a low downforce car here. So you can see the distance here - it's like four maybe five, six car lengths. It's pretty big on the high downforce car.

It's possible that if the car has enough downforce, it can transform what would be a double apex in other cars into a single apex because the line is so U-shaped. It's actually capable while being on the limit, hit the inside only once and then accelerate and start going wide and have the grip to do that while being on the limit.

Recap: Downforce Characteristics

To recap:

• Low downforce car: early turn in, early apex, big distance between the two apexes, and the car goes very wide in between

• The MRP (Minimum Radius Point) will always be in between the two apexes

• In a slightly higher downforce scenario: we turn in a little bit later, the distance between the apexes is much smaller now compared to when it was on the low downforce, the distance actually closed in a little bit, and the car still goes wide but a lot less

• It's a progression: we have less downforce, huge distance between the car and the inside in between the apexes, and then the more downforce we have, the closer it gets, the closer it gets, the closer it gets, all the way to the point where if you have enough downforce that actually becomes a single apex

Identifying Subtle Differences

Although it seems very clear in my illustrations, as always the differences in real life are actually pretty subtle. So as an exercise for you here, just try to notice the subtle differences between these characteristics: high downforce on the left, low downforce on the right, and identify whatever we discussed in this lesson in these videos. I'm not gonna show anything. I just want you to pay attention and turn your eyes for those subtle differences.

Notice the difference in:

• Turning points

• V shape versus U shape line

• How far apart are the apexes

• How far from the inside the car is by the time we start getting back on power