Fundamentals of Multiclass Racing

Multiclass racing is the pinnacle of endurance racecraft. Most high-level endurance events have multiple classes racing at the same time, and the good endurance drivers are the ones who don't believe in the story that dealing with traffic is about luck, but rather that it's about knowing exactly what to do in the most chaotic scenarios possible.

Core Principles and Values

The correct principles and values that will take you a long way as a racing driver are patience and respect. These are fundamental, and remember that each and every one on the track with you is doing their own race and battles. Having patience and respect does not mean losing time for the sake of others, it just means knowing how to execute moves and deal with the complex racing scenarios without destroying someone else's race in the process. Remember that in long events you can lap the same car several times, and they will remember what you did to them and how you dealt with them before.

Accepting Time Loss in Traffic

In multiclass racing you have to accept that you will lose time in traffic—it's just part of the game. There will always be moments that work out in our favor and the ones that work against us, but everyone goes through the same thing. The race will ebb and flow. Good racecraft is about managing that, maximizing the good moments and minimizing the bad ones.

In a long enough race, statistically speaking, everyone in your class will tend to have a similar amount of bad traffic compared to good traffic when it comes to dealing with other classes, slower or faster. Your job is to learn how to manage the bad ones to lose the least amount of time. If you can lose less time than your competitors, you're fine.

Communication Methods in Multiclass Racing

Car Placement

There are two ways you can communicate with the other cars in racing. The most important one is car placement. As the faster class, the way you're positioning your car behind someone else sends them a signal about what you're about to do. While racing, you can use your car placement to show intentions or to hide intentions and surprise your competitor. In multiclass racing, it's exactly the same thing, although you might want to be more predictable and help the cars ahead from the other classes to know exactly what you intend to do to prevent accidents.

Flashing Lights

The second way you can communicate with cars ahead of you is by flashing lights. You should combine flashing the lights with a clear car placement to signal exactly what you're going to do in the next corner with a slower class, for example.

Critical Responsibility Rules

What follows is the most important, most discussed but still the biggest cause of crashes when ignored: In multiclass racing, the faster car has the responsibility to move around the slower classes. The slower class should not try to help the faster car overtake them by actively moving outside their traditional racing line.

Overtaking Locations and Safety Levels

As the faster car, you can overtake a slow class on straights, after the corner exits, under braking into a corner, or mid-corner during long corners.

• The straights are definitely the safest

• Corner exits are the second safest

• Mid-corner overtakes will depend on the speed and length of the corner

For example, if you're in a car with more downforce, it's possible to overtake a GT car through the outside in a fast, long, sweeping corner. Passing under braking is also possible, although this is where you start getting into the more risky areas.

Understanding Risk Levels

Any overtake that requires that the slower class act upon it to prevent contact is already considered a high risk. For example, if you pass a slower class under braking, but by turn-in, you're already fully ahead, allowing them to turn into the corner similarly to what they would do alone, that is a low-risk move. But if you're far behind under braking, and by turn-in, you're still side-by-side preventing them from actually turning into the corner, that is already a high-risk move.

That does not mean you should never do a high-risk move. But you should know when it's worth it, like when you're fighting for a position with someone in your class, and you need that track position advantage.

Braking Zone Considerations

The faster class generally has better performance under braking and later braking points. So if you are the faster class, be careful to not stay behind slower classes during hard threshold braking zones, because they might be braking much earlier than you think. If you're close enough to have to worry about that, then the best move is to brake on the inside and make the pass on the inside ideally before turning in.

The Apex Problem

The worst place to be side-by-side with another class is at the apex. This is where you end up affecting the line of the slower class the most, and you can also potentially hurt your own lap times a bit too much. But there are scenarios where you should do it, especially when there are more than two cars involved.

Responsibilities and Best Practices

Faster Class Responsibilities

The faster car is responsible for letting the slower class know that they are about to make a move, especially if it's a higher-risk move like diving into the inside of a corner. This is where flashing and car placement will come in handy.

Slower Class Best Practices

The slower class should not try to move away from the racing line to help the faster class. A slower class with less downforce might have a different line or just be unable to adjust their line mid-corner without the risk of losing the car. So because of that, the faster class generally does the lane changes, as they most likely have more downforce and a more responsive car.

If you are the slower class, the safest approach is to just do your thing, except for when the faster class dive bombs you into the corner, which might require you to just delay your turning point a little bit.

The One Exception for Slower Class

As the slower class, there is one exception where you can help the faster class overtake you so that you both lose less time on straights before some corners. In some situations, it's better to lose a little bit of time, let the faster class pass you right before a braking zone, and then tuck in behind them and do your line normally. The faster the overtake is completed on you by a faster class, the earlier you can get back to your own rhythm. This is especially effective if you can use lifting and coasting to save some fuel.

Learning Through Track Time

There's nothing better than track time to identify the best overtaking spots at each race track. With enough practice, you will know exactly where you should be more aggressive and where you should wait and sacrifice some time for the sake of keeping your car intact.

Long-Term Consequences

Even if you complete a risky, aggressive move, the slower class will remember and it could affect how they will race you the next time you pass them. If your move was extremely aggressive, they could take precautions and drive more defensively to make sure they are safe the next time you overtake them. If the slower class makes it too difficult, the faster class might be more aggressive and take unnecessary risks, putting the slower class in danger or causing them time. In the end, it's always better to work together when possible.

Speed vs. Safety in Overtaking

Let's make an important distinction here. The overtake will not be safe or risky depending on how fast you do it. Actually, doing an overtake quickly and efficiently with clear car placement and decisively is the safest thing you can do. If you are close enough on a braking zone, it will be much safer to just dive bomb and get your car fully ahead by turn-in, even though the move looks risky—that's actually the best approach for you to get rid of that traffic fast.

The risky moves are those where you spend too much time side-by-side with other cars. For example, if you think about doing a move and you start doing it, but then you never really commit to finishing it fast, you're exposing yourself and the slower class to contact at a much higher risk, even though you're actually losing more time. You will be rewarded more for efficient overtakes that are done quickly.

Learning Reference Points

As the faster class, you will have to not only remember your own references, but actually pay attention and learn the references, cornering speeds and lines of the slower class. This will help you anticipate what they do and you can plan in time your overtake to be as efficient and safe as possible.

Specific Scenarios and Examples

Example: Boxing by Multiple Cars

This is an example of boxing, well more like being boxed by three cars at the same time, which is the worst case scenario for dealing with traffic and losing lots of positions at the same time. This car now has the option to move to the right and follow the pack while passing this car. He hesitated a little bit, he stayed behind the GT car and now as soon as he gets here, now it's too late for him to move away to the right and he is now being boxed by this car.

This is a high level race, so all these cars here know very well what boxing means and they just won't lose the opportunity to make the pass while keeping this car stuck in between this fast flowing lane here and this slow GT3 car. The opportunity here to go to the left was lost and then right now there's nothing he can do—he's just losing one, two, three positions and then finally he can get back but at this time he's already lost a lot of momentum because he had to lift.

It might have been possible that he actually got stuck right now because this curb is a little bit high, so because of that he could not really turn the car as much as he could as early as he could to the right and he preferred to be on the safe zone. Right now when he really tried it was too late—he realized that he was not clear anymore and he had to back off from the move which is the best decision at this point especially if this is a long race.

Example: Wrong Place for Dive Bomb

This is an example of where you should not try to overtake a slower class, when the braking zone is very short and you're just touching the brakes one, two, five, ten percent to rotate the car and you're already turning in—if there's no straight line braking then that should not be a place to dive bomb and this is exactly what he tried. He tried to turn in and go to the inside just trusting on the extra minimum speed that he could carry but the other car was already turning in.

It's very important to know that the lines that a high downforce car takes are more U-shaped so they can actually turn in a little bit later, but the lines of a GT3 car are more V-shaped so they have to turn in very early—earlier than this car is used to—which might have made him think that he could pull this move. This is why it's so important for the GTP cars to understand that the V-shaped approach makes all the GT cars turn in earlier in all these fast corners and this is why you should never try to make a move in such a corner like Kink's Glenn left corner.

What he should do instead is just wait on the inside and then pass them after the exit so that things like this don't happen.

Example: Two Choices at Corner Entry

In this example we have two choices: we could dive bomb on the inside right now or we could lift a little bit, save a tiny bit of fuel, prepare a very late apex, try to carry as much speed as possible on the exit and make the pass right after the exit. You can see that you could potentially gain a little bit of time or lose the least time by dive bombing on the inside right here but this is definitely higher risk than just waiting on the outside and then trying to get a late apex faster exit.

Again depending on the situation of the race—if it's a short race and you have a few laps to go and you're being chased by someone—it might be a good move to actually try the higher risk and dive bomb on the inside a little bit. But if this is a very long race, if you're doing a 6 hour, 12 hour, 24 hour race, it makes absolutely no sense to dive bomb like that because the risk might be just a little bit too high.

Example: Passing on the Outside with High Downforce

This is a very good example of how to pass on the outside with a high downforce car as the faster class. So the duty of the slower class here is to do nothing—literally just do their line which is actually this one. Generally on this corner the GT cars they just prepare their line because they really want to be on this area here so they never go out that wide anyways. Their line is actually staying going out more or less to the middle of the track and then already preparing their braking zones around these cones.

Because the higher downforce car driver knows that he already can plan to just carry as much speed as possible and pass them on the outside because this corner is pretty easy for their car and then he actually gets fully ahead and can brake normally into the corner by losing the least time possible.

Example: Lack of Assertiveness with Car Positioning

This is an example of how much time you can lose if you're not assertive with your car positioning. In this lap the faster class is on the outside side by side, now he's free to use the apex but he actually doesn't—he misses the apex a little bit and then right now he finds himself being slightly boxed and he's stuck in between these two cars on the left lane and he's passed.

So this is actually a mistake—he was trying to be safe around here by not really getting to the right lane and trying to follow this car he fell to this side by missing the apex and now he is stuck. Of course at this point there's kind of nothing you can do because you already know that a faster car is passing you even though it's for position there's nothing you can do.

So the mistake here was actually on the change of direction—right now he could have turned right a tiny bit earlier to actually use this apex but because he missed it now he's falling all the way to the outside line and then now he's blocked and there's nothing he can do.

Example: High Risk Move with Two Slower Classes

This is an example of just a very stupid high risk move—there are two slower classes pretty far ahead fighting side by side into a very low speed chicane and he for some reason decides to try to go to the inside and then he realizes that he's not going to be able to do it so now he's trying to brake harder on a straight line and trying to avoid contact and really trying to just stop the car.

As you can see the decision was taken right here—he could have just waited and placed his car right here and tried to make a pass on the exit which is the safest way but he decided to do something that was never going to work and then now he's just trying to avoid a crash which doesn't happen. He ends up getting contact potentially getting damage in his front splitter and potentially losing seconds per lap because of the damage.

Example: Patience in Fast Sections

Still talking about patience—now this is a situation where there's nothing you can do. Whenever we have very fast sections like Road Atlanta sector 2, you really can't pass anyone on the outside here as a fast car and the reason is that the corners are not long. So let's talk about that—I told you that you can pass cars on the outside if you have a long corner but these corners are short. They are one corner, one corner—because these are many changes of directions at a short period of time you can't pass on the outside because the GT cars are trying to straighten this out as much as possible and they don't have a lot of grip. They're barely doing this flat and because of that you will never have enough time to pass them in each of these sections.

So because you cannot pass, the best approach is to just wait—you lift and you wait and you wait and you wait and you wait and then here you're gonna try to get a good exit and pass them on this straight. There's nothing you can do—it's gonna happen to everyone if you're racing at Road Atlanta and you get here and you're behind slower traffic just wait.

Even if you're patient in the esses, you have the choice to try to go to the inside here before this last left but again I also don't recommend this because the turn-in point is very early for the GT car—earlier than you ever think—and because of that if you try to dive bomb here he is going to turn in on you and there's a very high risk of contact because this braking zone is very short. They are not braking on a straight line for too long—they're braking 30, 40, 50% and then already starting to turn in very early which might surprise you if you try to go on the inside. So even on this corner, turn 5, wait and get a better exit instead.

Advice for GT Cars

As the GT car if you're driving and you see an LMP behind you just do your line—don't panic. If you're driving in a very good field they are not going to try anything. So what you can do actually is to just do your line. What I see happening a lot is a driver like this being afraid of the car and actually opening up and totally screwing their own line because they are afraid that the LMP is gonna turn on them.

Actually this is a self-fulfilling prophecy—if you actually go to the outside because you're afraid of them going, well you're signaling that you're leaving space for them and then they go. Because they were not planning on doing that but they saw your positioning and now they're trying to go—that is what might cause the crash. So be assertive that you are taking your line, turn in where you generally turn and then they will wait and pass you after the exit.

Exception at Road Atlanta

One exception for Road Atlanta—it's before the fast esses you have this quite long left-hander after the blind right. In this one it is possible that the GT cars will pass you but it gets a little bit tricky if they're not cleared by here. So this is where the right left right starts and as you can see right now because the LMP car is trying to pass two cars at the same time he ends up affecting the line and scaring this guy here and because of that he ends up losing his own position to the other car which sees that opportunity. It sees that he is scared by the LMP and then chooses to just pass him on the outside which is again kind of a risky move for both cars but it ends up working especially if this is a high level race—they will never lose that opportunity and just brake behind the other car that got scared.

As the LMP car here I would say this is not such high risk because as you can see right now they already have the right to do the line—they are definitely badly affecting the performance of this GT car but it's justifiable because he was trying to pass two cars at the same time and by the time you're here you can't do anything as the LMP car because there's someone on your side. So in this case because you can't really tuck in the inside and wait the only option you have is to actually just take the high risk move and pass them on the next right hander.

As you can see you have to read the situation right here—if you are going to pass one car you have to commit to pass both of them because it's just not gonna work to pass one and then hesitate and start braking right here. As this car I think it was a mistake for them to turn in so late—there was plenty of space to start turning in a little bit earlier and still be on the line and defend the position. And as the orange car this was a great opportunity to notice that as soon as this car turns in a little bit too late he takes the line and goes flat and makes the move.

This is the worst possible scenario for an LMP car in this sector at Road Atlanta but you can't lose more time than this—you already lose a lot of time by being behind the GT car and knowing that there's nothing you can do without taking too much risk in these esses. But if they are side by side fighting that's even worse.

Example: Reading Opportunities

What you can do here is honestly just wait and wait and wait and then he finds a possibility to just stay close to the next car and now he's really losing his patience and as soon as he sees again—he sees the GT car moving towards the right, this car positioning, this car direction is signaling "hey take this line," it's automatic it's instinctive and as soon as this happens, as soon as the car goes back to the right the LMP sees the opportunity and just tucks in on the inside.

And now what's cool to see is that as the yellow GT car, as the Mercedes, he sees that this car is now startled by the LMP and what he's gonna do is tuck in on the inside and also make the move and make the pass. So you see how many situations are possible in just one sector just because three cars are involved, one being a different class, and you're going to learn all these dynamics by doing hundreds and hundreds of laps always trying to analyze the replays, always trying to be aware of what decisions you're taking and also opening your mind for the subtleties, for what the other cars are doing in terms of signaling, from what you can do to signal what you're going to do and also just positioning your car in a way that makes you lose the least time possible in the safest way possible.

Example: GT3 Lifting Before Corner

This is a very good example of a GT3 car doing a lift before the corner just so they don't do this Monza turn one side by side which allows him to get a much better exit and not lose so much time. What he does here is he's lifting a little bit before the braking, leaving enough room for the hypercar just so that he can do the corner behind him and not have to worry about going side by side in such a slow corner. This is one of the few scenarios, the few corners where many of the GT3 drivers decide to stay on the inside to let faster cars pass.

Example: Road Atlanta Blind Corner

This is the blind corner, the second corner of Road Atlanta and many drivers on the GT class choose to stay on the inside to allow the LMP line to flow more quickly and so that they can get rid of them as quickly as possible. Generally what happens if you stay right here is that the LMP cars tend to be a little bit too aggressive and clumsy and they sometimes hit this curb and go wide making the whole situation a lot more dangerous. So we do see a lot of drivers taking this line, letting them go as quickly as possible and then just continue with their lives.

As you can see here it ends up being way safer for the GT car and this is actually a good thing for the LMP cars as well. So as you can see for the red car he knew he was so clear that he could actually just take the apex normally and the blue car was not so sure about being clear so he actually gave a little bit extra space right here. You can see him not fully taking the apex just because he was not 100% confident that this car was gonna give enough space. Of course this is just an awareness thing because right now he doesn't have any overlap anymore so he could have turned but a little bit too close for comfort.

Example: Turn-In Without Awareness

This is a scenario where the GT3 car could have lifted a little bit to make their lives easier and he just tried to go as fast as possible. They are side by side and he literally just turns in—there is no point in discussing whether the hypercar should have done the move or not. As soon as he is here, now you have to take a decision—the car is already side by side. It doesn't matter if he's right or if he's wrong—you are already side by side and you need to do something to lose the least time possible.

So what you can do here really is just wait and the best way for both drivers right now would be for the GT car to abandon the turn-in point and just wait a little bit, brake for longer on a straight line, wait for both cars to be lined up and then follow the GT car. But what the GT3 car tried to do was literally turn in on the hypercar and then try to carry as much speed as possible and actually still do the side by side on the second corner as well which made them both lose a stupid amount of time.

Example: Passing on Outside of Long High Speed Corner

This is a very good example of the faster class passing the slower class on the outside of a very long high speed corner. Here the cars can easily overtake on the outside with no problem and this Porsche GT3 just waits on the inside line knowing that there's a long fleet of LMP cars passing them on the outside and this is totally fine and this happens normally at Road Atlanta on this last corner.

The problem is that in a situation where the two LMPs are actually side by side and fighting, this car here decided to take the inside and this is going to be a big problem for the Porsche because they don't have enough downforce to take that corner. So what happens is now the yellow car blocks the line, even not using enough of the inside here, placing this Porsche in the terrible situation and then because of that now this car decides to follow him because he definitely carries a lot more speed than the Porsche and he's just trying to follow the flow of the yellow car and preventing this car from also following it.

So this guy is not boxed—he does not want to be boxed behind the GT car. His move is definitely going to be to go to the right and because of that now everyone is on the inside. The Porsche doesn't have anything he could do right now—he's just struggling for his life and the flow of the LMP3s goes to the inside where the GT3 car is actually in big trouble going through the grass.

Not ideal scenario but you can't really blame anyone because this is a very very complex scenario. As the yellow car I would have done exactly the same thing—you would have done exactly the same thing. It's just a very very unfortunate scenario for the Porsche. I don't think they could have done anything differently because this line is the line the Porsche should take. If he went to the inside a little bit too early it would be probably even worse for him. Not really sure—maybe he could have lifted or gone to the right. Very difficult scenario—we would have to try again and again and again and again to see what would be the best move for the Porsche but yeah very unfortunate. It happens. No one crashed though so we're good.

Example: Fleet of LMP3s on Outside

This is another example of the fleet of LMP3s just following on the outside line which is very regular. In this case here the BMW actually has to slow down a little bit because they are doing this corner flat if they use all the track but because he's turning in from the inside this is not enough of a radius for him—he will actually have to lift a tiny bit here. But again there's nothing he can do—there are lots of cars passing them and they're not gonna slow down for him at this point.

Example: Lack of Awareness from GT3 Car

This is a scenario of lack of awareness from a GT3 car. He can easily stay on the inside right here and follow this line close to the white line which is actually faster for him but he doesn't really realize that there are two hypercars passing him and he's just drifting very slowly to the outside in a very unaware manner which makes this car brake hard which is very dangerous and also makes the other hypercar have to brake.

So just don't be this guy—always look in mirrors especially if you are a slower class in a multiclass event to make sure that these things don't happen. Because this guy decided to brake but what if he hadn't? What if he actually gone for it? Maybe he would hit the grass, maybe he would lose the car and hit you and everything. So this scenario is bad for everyone. If you already did the corner, look in your mirrors, make sure that you're staying on the fastest line for you but don't go very slowly to the middle of the track like that because that is putting yourself in a very dangerous situation.

Example: Fast Decision Based on Hesitation

This is a very good example of a very very fast decision based on a mistake or a hesitation from someone ahead of you from the same class. So this guy is thinking about dive bombing this slower class but he gives up—as you can see he goes to the inside, he starts braking, he's like "ah no I'm not going" but now you can see how he's really slower than the car behind and now the best decision right now is to do a surprise attack and actually go to the inside and make the pass on the car from the same class.

As you can see this black car is just using the opportunity and hesitation from the car ahead that was caused by this slower class. You have to read the scenarios—you have to see what's happening ahead. Right now as a driver here he's not thinking about anything—he's just seeing what's happening. He's just seeing the two cars ahead and he's like "ah what what is he gonna do maybe he's gonna try the inside oh actually he gave up oh wow he braked early I'm going to the inside."

So all those thoughts happen very very quickly in a multiclass scenario and this driver did not hesitate in seeing that opportunity and going for the inside and making a very good move.

Example: High-Risk Move with Two Cars

This is another example of a high-risk move that you end up having to do because you're passing two cars. So because he's passing two cars at the same time right now there's nothing he can do—he's already side by side, he's boxed here from this car and the only way is forward. Even though this is not a very hard braking zone he has to go for it so he decides to go to the inside and brake late and take the line even if that means putting this car in slight danger.

Actually what he did here was to just be outside of the track usage—he should have been using a lot more of this track here and turning in normally. If you look at the actual full speed the move was not too risky for the LMP car but what happens is that this car, the black Porsche, actually brakes a little bit early and he's not using the track and he causes the Mercedes to hit him. So there is a little bit of contact here but that's not the fault of the LMP3 car. If I was this car I would do exactly the same.

Example: Planning for Safest Pass

This is another very good example of patience and planning your pass to be in the safest scenario possible. Right now he has clearly the opportunity to go to the inside here on the left but he knows—he probably understands that all the GT cars have to bring the car as much as possible to the left because this corner is very difficult for them. So what he does—he waits, he waits, he lifts and now he's just planning his line to go all the way to do a late apex here and make the pass after the exit.

It's funny that this Porsche here was aware that there was an LMP3 here and he actually thought about leaving the space. If you look at this replay here you will see that the Porsche went to the inside and left this space for the LMP so he was ready for the LMP to do a more risky move but the LMP had not done it. So this is a very common scenario where two drivers are being overly gentle with each other which is good—it's just making sure that they are not having any contact in the multiclass race like that.

Example: Clearing Early in Short Braking Zone

This is another example where this corner is just a little bit of braking for the BMW but barely any braking for the LMP. So as long as he clears himself very early it's all good and you can see that he's really not affecting so much the line of the BMW. So that is a very good move.