Case Study 1 — 610 iRating
Lesson
5
of
7
Lesson by
Suellio Almeida
Lesson by
Suellio Almeida
Mark as Finished
First Case Study Analysis: 610 i-Rating Driver
This case study examines a driver with a 610 i-rating on the Caterham Academy course. We'll analyze the lap corner by corner to identify opportunities for improvement and lap time gains.
Turn One: Braking and Initial Turn-In
Slow Braking Application
The first major issue is the braking approach, which shows symptoms of fear or uncertainty. This hesitation creates several problems:
The driver approaches the brakes very slowly, gradually building pressure
The brake pressure progression goes from 10% to 30% to 50% to finally 70% (maximum without locking)
This gradual application causes the car to travel excessive distance before reaching peak pressure
For example, if using the 100-meter board as a braking reference, the slow pressure application means the car travels significant distance before reaching proper braking force. This distance should be compressed. Breaking more quickly to the desired pressure allows for a more reliable braking reference and better consistency. We want to always use the same pressure to be able to replicate and repeat that consistently.
Think of the braking trace in 3D: the current approach creates a long, gradual wall where deceleration only becomes effective after traveling excessive distance. The ideal is a steeper wall where brakes reach higher pressure from the beginning, creating predictable, easy-to-understand deceleration that allows carrying more speed into the corner.
Creeping Into the Corner
The second issue involves the transition from braking to turning. When the steering is straight and the car approaches the corner, there's a problem: the car travels on a straight line, drifting diagonally without actually creating the lateral force needed.
What we want to do is create one single arc that builds up all the way to the maximum rotation point. We want to have more and more rotation, ensuring that speed goes down and rotation goes up accordingly. This creeping motion prevents building up one consistent motion.
The correct approach:
Brake on the white line and stay on it until ready to turn
Commit to one rotation when initiating the turn
Build up one single motion that allows good pointing and earlier acceleration
Don't be a creep—brake on a straight line until you decide this is the point where you start turning. This doesn't mean you have to turn fast; it means you have to initiate one consistent motion that builds up in itself.
Brake Release and Steering Correlation
The driver adds a little bit of steering and then completely drops the brakes before adding more steering. Looking at the trace: the steering starts to show up very hesitantly, then the brakes drop quickly. This creates a problematic combination:
At 50% brakes and 10 degrees of steering, the brakes suddenly drop to 5%
The steering only increases from 10 to 15 degrees
This doesn't make sense because we want to inversely correlate both inputs
The more steering we add, the less brakes we have. If we drop the brakes very quickly, technically we should add a lot of steering, which wouldn't work either. The solution is not to steer faster because you're releasing the brake so fast—just don't release the brakes fast in the first place. Allow that transition to happen more smoothly so you don't lose fronts. You want the front to bite.
Understanding Oversteer and Front Tire Grip
An important concept: if the front tires are biting and you're getting oversteer, good job. Oversteer is good—learn how to manage and adjust it. Get used and comfortable with oversteer, because oversteer means you're giving a lot of grip to the front tires.
Key principle: If you overdrive the front tires you get understeer. If you underdrive the front tires you also get understeer. Understeer is a punishment for both overloading the fronts and underloading them. When you do get oversteer on the late entry before the apex, that means you're actually pretty close to the ideal.
We need to spend time dealing with that ideal grip on the front tires, which will mean dealing with oversteer on the late entry before the apex. That's where we really need some rotation, because the more rotation we get there, the earlier we can accelerate—and that's how we gain time.
Premature Throttle Application
When the car starts to rotate, the driver goes to throttle too early. As soon as the throttle is touched, the car immediately pushes wide and loses rotation. This 40% throttle application is still not enough to continue the rotation—it's going to push the car and induce a lot of understeer.
This understeer prevents the driver from accelerating fully afterward. The throttle here is against the throttle: if you accelerate that early you kill the rotation, and if you kill the rotation, you're not pointed to the exit, which means you cannot actually go to 100%. The driver has to lift, wait, and finally go to 100%. This costs four tenths of lap time.
The Long Closing Spiral Corner
This corner is difficult because it requires a long closing spiral. The radius of this corner is smaller than the previous section, so we can do a much wider arc and then close in. We're essentially building a closing spiral: turning more, more, more, more until the maximum rotation point.
The spiral starts early and never stops—you keep adding, adding, adding, getting more rotation until the maximum rotation point. This is the difficult thing for beginners to understand.
Braking and Speed Carry Analysis
Looking at the inputs: the driver brakes on a straight line (good, not creeping) and stays pretty close to the white line. He starts to turn where he's supposed to initiate the arc (also good), but he's braking too much and too early. Then he releases the brake and is already accelerating.
The problem: if we're getting back on throttle, the speed should go down up to the maximum rotation point. At only 5% throttle, the speed is still going down (74, 73 kilometers per hour), and then finally the driver starts to accelerate more—enough to maintain 74, then the speed comes up a little bit.
We really want that increasing rotation all the way to the maximum rotation point. Technically the speed graph looks right because minimum speed was reached at the correct point, but having to accelerate so early and wait, wait, wait while maintaining very low speed means the driver could have carried more speed from earlier in the corner.
Better approach:
Instead of braking hard early, brake later and softer
Carry more energy through the corner
Force the braking to continue longer
Still arrive at the minimum speed point at 74 km/h, but win half a second to one second of lap time
Throttle Hold and Understeer
After braking early, the driver holds a very tiny amount of throttle, which makes the balance comfortable. This is literally what we teach when it comes to inducing understeer, but this understeer is not the way you're going to drive fast—it's the way you're going to understand the grip.
After understanding understeer, you have to clean it up and make sure the car rotates as much as possible when you're comfortable with it. The progression is:
Learn how to induce understeer
Learn how to induce oversteer
Find the middle point and try to rotate the car as much as possible without losing the rear
In this corner: too early braking, then coast and hold the throttle, creating a waiting moment. The driver was on throttle so early while steering was still increasing—this shows that at the maximum rotation point you're maybe on the good limit, but all the earlier area was under limit because there wasn't enough steering and not enough throttle. Obviously you could not have accelerated because the corner radius was too close, but this was all caused by braking too early instead of braking less and carrying that all the way to the maximum steering point.
Subsequent Corners: Pattern Recognition
Left-Hander and Trail Braking
The left-hander is a consequence of all the issues from the previous corner. The braking here is better and makes more sense than turn one—there is trailing, but a little bit too much trailing.
What happened: the driver trailed and then suddenly the car is turning more than necessary, which forces early acceleration. This is bouncing off the apex. We are bouncing off the apex because the trail was too heavy. The driver trailed heavily and then immediately had to accelerate, making "this part too fat."
Better approach: start to release a little bit earlier to carry a little bit more speed and not have the car go unnecessarily to that point. Instead of bouncing, go around that part and don't get stuck before hitting the curb.
Trail Braking Purpose
Too much trailing here. Trail only enough. Why do we trail? Because you want to turn the car. If you're already getting the rotation, let go—release the brakes, because trailing costs you speed. You're paying the price; you're paying minimum speed to be able to get that rotation.
If you don't need that rotation, you're almost literally wasting your speed with no reward.
Mid-Corner Rotation Issues
Up to the turn-in point, everything looks good. Then the problem appears: the driver adds throttle right when rotation is needed. As soon as this happens, the car doesn't want to turn. This completely prevents the rotation from happening because we're getting back on throttle too early.
Look at how long the driver has to hold it—the car doesn't want to turn, doesn't want to go faster. The speed is literally still going down, so that's not enough throttle to even contain the fact that the speed is going down, but that throttle is definitely severely preventing the rotation from happening. This costs a lot of lap time.
What we need: trail, keep turning, keep trailing, get to the maximum rotation point, and then get back on power. What happened instead: trail, then enter no-man's land just understeering forever. The throttle is causing this problem.
Over-Braking Pattern
Same problem appears again: too much brakes forces the use of throttle that early. This kind of controls the rotation—you're not going to hit the grass, but you're not using the rear tires. It's unnecessary.
The car was going to turn way more than needed, but the driver held the brakes so hard the car was overslowed. Now the driver can already get back on throttle, and even on the throttle that's supposed to cause understeer, they still were able to hit the apex. This means you can brake a lot less into this corner.
Key Takeaways and Recommendations
Trail Braking Technique
For this driver specifically, you really need to find the use of the little trail. This little trail is super important. If you learn how to combine this with the steering as the steering goes up, up, up, up, up, and you're combining that to make this feel good, you have to carry enough speed.
If you brake too hard and can already go on throttle, that means you're way too slow. We want to be trailing. We want to carry more speed so that the trail braking is necessary to turn the car.
If you're too slow: no need for trail braking
If you're fast without trail braking: you understeer and go off
If you're fast with trail braking: you need the trail braking to stay on the line and get the rotation that's necessary
That's how you find the lap time and carry more speed into the corner in the first place.
Summary of Issues
This case study reveals lots of little things. This car will definitely be perfect for developing these areas, and these issues are likely present in other cars—this car just reveals them more.
The most important thing is the mid-corner rotation. Look for the mid-corner rotation. You need to continuously get the car to turn and need that rotation by:
Carrying a little bit more speed
Dealing with the entry oversteer
Mid-corner: turning the steering more
Using that one to ten percent brakes
Feeling that point before you get into the shoot phase
Point so that you can shoot. More laps, more laps, more laps—practice these concepts consistently.
First Case Study Analysis: 610 i-Rating Driver
This case study examines a driver with a 610 i-rating on the Caterham Academy course. We'll analyze the lap corner by corner to identify opportunities for improvement and lap time gains.
Turn One: Braking and Initial Turn-In
Slow Braking Application
The first major issue is the braking approach, which shows symptoms of fear or uncertainty. This hesitation creates several problems:
The driver approaches the brakes very slowly, gradually building pressure
The brake pressure progression goes from 10% to 30% to 50% to finally 70% (maximum without locking)
This gradual application causes the car to travel excessive distance before reaching peak pressure
For example, if using the 100-meter board as a braking reference, the slow pressure application means the car travels significant distance before reaching proper braking force. This distance should be compressed. Breaking more quickly to the desired pressure allows for a more reliable braking reference and better consistency. We want to always use the same pressure to be able to replicate and repeat that consistently.
Think of the braking trace in 3D: the current approach creates a long, gradual wall where deceleration only becomes effective after traveling excessive distance. The ideal is a steeper wall where brakes reach higher pressure from the beginning, creating predictable, easy-to-understand deceleration that allows carrying more speed into the corner.
Creeping Into the Corner
The second issue involves the transition from braking to turning. When the steering is straight and the car approaches the corner, there's a problem: the car travels on a straight line, drifting diagonally without actually creating the lateral force needed.
What we want to do is create one single arc that builds up all the way to the maximum rotation point. We want to have more and more rotation, ensuring that speed goes down and rotation goes up accordingly. This creeping motion prevents building up one consistent motion.
The correct approach:
Brake on the white line and stay on it until ready to turn
Commit to one rotation when initiating the turn
Build up one single motion that allows good pointing and earlier acceleration
Don't be a creep—brake on a straight line until you decide this is the point where you start turning. This doesn't mean you have to turn fast; it means you have to initiate one consistent motion that builds up in itself.
Brake Release and Steering Correlation
The driver adds a little bit of steering and then completely drops the brakes before adding more steering. Looking at the trace: the steering starts to show up very hesitantly, then the brakes drop quickly. This creates a problematic combination:
At 50% brakes and 10 degrees of steering, the brakes suddenly drop to 5%
The steering only increases from 10 to 15 degrees
This doesn't make sense because we want to inversely correlate both inputs
The more steering we add, the less brakes we have. If we drop the brakes very quickly, technically we should add a lot of steering, which wouldn't work either. The solution is not to steer faster because you're releasing the brake so fast—just don't release the brakes fast in the first place. Allow that transition to happen more smoothly so you don't lose fronts. You want the front to bite.
Understanding Oversteer and Front Tire Grip
An important concept: if the front tires are biting and you're getting oversteer, good job. Oversteer is good—learn how to manage and adjust it. Get used and comfortable with oversteer, because oversteer means you're giving a lot of grip to the front tires.
Key principle: If you overdrive the front tires you get understeer. If you underdrive the front tires you also get understeer. Understeer is a punishment for both overloading the fronts and underloading them. When you do get oversteer on the late entry before the apex, that means you're actually pretty close to the ideal.
We need to spend time dealing with that ideal grip on the front tires, which will mean dealing with oversteer on the late entry before the apex. That's where we really need some rotation, because the more rotation we get there, the earlier we can accelerate—and that's how we gain time.
Premature Throttle Application
When the car starts to rotate, the driver goes to throttle too early. As soon as the throttle is touched, the car immediately pushes wide and loses rotation. This 40% throttle application is still not enough to continue the rotation—it's going to push the car and induce a lot of understeer.
This understeer prevents the driver from accelerating fully afterward. The throttle here is against the throttle: if you accelerate that early you kill the rotation, and if you kill the rotation, you're not pointed to the exit, which means you cannot actually go to 100%. The driver has to lift, wait, and finally go to 100%. This costs four tenths of lap time.
The Long Closing Spiral Corner
This corner is difficult because it requires a long closing spiral. The radius of this corner is smaller than the previous section, so we can do a much wider arc and then close in. We're essentially building a closing spiral: turning more, more, more, more until the maximum rotation point.
The spiral starts early and never stops—you keep adding, adding, adding, getting more rotation until the maximum rotation point. This is the difficult thing for beginners to understand.
Braking and Speed Carry Analysis
Looking at the inputs: the driver brakes on a straight line (good, not creeping) and stays pretty close to the white line. He starts to turn where he's supposed to initiate the arc (also good), but he's braking too much and too early. Then he releases the brake and is already accelerating.
The problem: if we're getting back on throttle, the speed should go down up to the maximum rotation point. At only 5% throttle, the speed is still going down (74, 73 kilometers per hour), and then finally the driver starts to accelerate more—enough to maintain 74, then the speed comes up a little bit.
We really want that increasing rotation all the way to the maximum rotation point. Technically the speed graph looks right because minimum speed was reached at the correct point, but having to accelerate so early and wait, wait, wait while maintaining very low speed means the driver could have carried more speed from earlier in the corner.
Better approach:
Instead of braking hard early, brake later and softer
Carry more energy through the corner
Force the braking to continue longer
Still arrive at the minimum speed point at 74 km/h, but win half a second to one second of lap time
Throttle Hold and Understeer
After braking early, the driver holds a very tiny amount of throttle, which makes the balance comfortable. This is literally what we teach when it comes to inducing understeer, but this understeer is not the way you're going to drive fast—it's the way you're going to understand the grip.
After understanding understeer, you have to clean it up and make sure the car rotates as much as possible when you're comfortable with it. The progression is:
Learn how to induce understeer
Learn how to induce oversteer
Find the middle point and try to rotate the car as much as possible without losing the rear
In this corner: too early braking, then coast and hold the throttle, creating a waiting moment. The driver was on throttle so early while steering was still increasing—this shows that at the maximum rotation point you're maybe on the good limit, but all the earlier area was under limit because there wasn't enough steering and not enough throttle. Obviously you could not have accelerated because the corner radius was too close, but this was all caused by braking too early instead of braking less and carrying that all the way to the maximum steering point.
Subsequent Corners: Pattern Recognition
Left-Hander and Trail Braking
The left-hander is a consequence of all the issues from the previous corner. The braking here is better and makes more sense than turn one—there is trailing, but a little bit too much trailing.
What happened: the driver trailed and then suddenly the car is turning more than necessary, which forces early acceleration. This is bouncing off the apex. We are bouncing off the apex because the trail was too heavy. The driver trailed heavily and then immediately had to accelerate, making "this part too fat."
Better approach: start to release a little bit earlier to carry a little bit more speed and not have the car go unnecessarily to that point. Instead of bouncing, go around that part and don't get stuck before hitting the curb.
Trail Braking Purpose
Too much trailing here. Trail only enough. Why do we trail? Because you want to turn the car. If you're already getting the rotation, let go—release the brakes, because trailing costs you speed. You're paying the price; you're paying minimum speed to be able to get that rotation.
If you don't need that rotation, you're almost literally wasting your speed with no reward.
Mid-Corner Rotation Issues
Up to the turn-in point, everything looks good. Then the problem appears: the driver adds throttle right when rotation is needed. As soon as this happens, the car doesn't want to turn. This completely prevents the rotation from happening because we're getting back on throttle too early.
Look at how long the driver has to hold it—the car doesn't want to turn, doesn't want to go faster. The speed is literally still going down, so that's not enough throttle to even contain the fact that the speed is going down, but that throttle is definitely severely preventing the rotation from happening. This costs a lot of lap time.
What we need: trail, keep turning, keep trailing, get to the maximum rotation point, and then get back on power. What happened instead: trail, then enter no-man's land just understeering forever. The throttle is causing this problem.
Over-Braking Pattern
Same problem appears again: too much brakes forces the use of throttle that early. This kind of controls the rotation—you're not going to hit the grass, but you're not using the rear tires. It's unnecessary.
The car was going to turn way more than needed, but the driver held the brakes so hard the car was overslowed. Now the driver can already get back on throttle, and even on the throttle that's supposed to cause understeer, they still were able to hit the apex. This means you can brake a lot less into this corner.
Key Takeaways and Recommendations
Trail Braking Technique
For this driver specifically, you really need to find the use of the little trail. This little trail is super important. If you learn how to combine this with the steering as the steering goes up, up, up, up, up, and you're combining that to make this feel good, you have to carry enough speed.
If you brake too hard and can already go on throttle, that means you're way too slow. We want to be trailing. We want to carry more speed so that the trail braking is necessary to turn the car.
If you're too slow: no need for trail braking
If you're fast without trail braking: you understeer and go off
If you're fast with trail braking: you need the trail braking to stay on the line and get the rotation that's necessary
That's how you find the lap time and carry more speed into the corner in the first place.
Summary of Issues
This case study reveals lots of little things. This car will definitely be perfect for developing these areas, and these issues are likely present in other cars—this car just reveals them more.
The most important thing is the mid-corner rotation. Look for the mid-corner rotation. You need to continuously get the car to turn and need that rotation by:
Carrying a little bit more speed
Dealing with the entry oversteer
Mid-corner: turning the steering more
Using that one to ten percent brakes
Feeling that point before you get into the shoot phase
Point so that you can shoot. More laps, more laps, more laps—practice these concepts consistently.
First Case Study Analysis: 610 i-Rating Driver
This case study examines a driver with a 610 i-rating on the Caterham Academy course. We'll analyze the lap corner by corner to identify opportunities for improvement and lap time gains.
Turn One: Braking and Initial Turn-In
Slow Braking Application
The first major issue is the braking approach, which shows symptoms of fear or uncertainty. This hesitation creates several problems:
The driver approaches the brakes very slowly, gradually building pressure
The brake pressure progression goes from 10% to 30% to 50% to finally 70% (maximum without locking)
This gradual application causes the car to travel excessive distance before reaching peak pressure
For example, if using the 100-meter board as a braking reference, the slow pressure application means the car travels significant distance before reaching proper braking force. This distance should be compressed. Breaking more quickly to the desired pressure allows for a more reliable braking reference and better consistency. We want to always use the same pressure to be able to replicate and repeat that consistently.
Think of the braking trace in 3D: the current approach creates a long, gradual wall where deceleration only becomes effective after traveling excessive distance. The ideal is a steeper wall where brakes reach higher pressure from the beginning, creating predictable, easy-to-understand deceleration that allows carrying more speed into the corner.
Creeping Into the Corner
The second issue involves the transition from braking to turning. When the steering is straight and the car approaches the corner, there's a problem: the car travels on a straight line, drifting diagonally without actually creating the lateral force needed.
What we want to do is create one single arc that builds up all the way to the maximum rotation point. We want to have more and more rotation, ensuring that speed goes down and rotation goes up accordingly. This creeping motion prevents building up one consistent motion.
The correct approach:
Brake on the white line and stay on it until ready to turn
Commit to one rotation when initiating the turn
Build up one single motion that allows good pointing and earlier acceleration
Don't be a creep—brake on a straight line until you decide this is the point where you start turning. This doesn't mean you have to turn fast; it means you have to initiate one consistent motion that builds up in itself.
Brake Release and Steering Correlation
The driver adds a little bit of steering and then completely drops the brakes before adding more steering. Looking at the trace: the steering starts to show up very hesitantly, then the brakes drop quickly. This creates a problematic combination:
At 50% brakes and 10 degrees of steering, the brakes suddenly drop to 5%
The steering only increases from 10 to 15 degrees
This doesn't make sense because we want to inversely correlate both inputs
The more steering we add, the less brakes we have. If we drop the brakes very quickly, technically we should add a lot of steering, which wouldn't work either. The solution is not to steer faster because you're releasing the brake so fast—just don't release the brakes fast in the first place. Allow that transition to happen more smoothly so you don't lose fronts. You want the front to bite.
Understanding Oversteer and Front Tire Grip
An important concept: if the front tires are biting and you're getting oversteer, good job. Oversteer is good—learn how to manage and adjust it. Get used and comfortable with oversteer, because oversteer means you're giving a lot of grip to the front tires.
Key principle: If you overdrive the front tires you get understeer. If you underdrive the front tires you also get understeer. Understeer is a punishment for both overloading the fronts and underloading them. When you do get oversteer on the late entry before the apex, that means you're actually pretty close to the ideal.
We need to spend time dealing with that ideal grip on the front tires, which will mean dealing with oversteer on the late entry before the apex. That's where we really need some rotation, because the more rotation we get there, the earlier we can accelerate—and that's how we gain time.
Premature Throttle Application
When the car starts to rotate, the driver goes to throttle too early. As soon as the throttle is touched, the car immediately pushes wide and loses rotation. This 40% throttle application is still not enough to continue the rotation—it's going to push the car and induce a lot of understeer.
This understeer prevents the driver from accelerating fully afterward. The throttle here is against the throttle: if you accelerate that early you kill the rotation, and if you kill the rotation, you're not pointed to the exit, which means you cannot actually go to 100%. The driver has to lift, wait, and finally go to 100%. This costs four tenths of lap time.
The Long Closing Spiral Corner
This corner is difficult because it requires a long closing spiral. The radius of this corner is smaller than the previous section, so we can do a much wider arc and then close in. We're essentially building a closing spiral: turning more, more, more, more until the maximum rotation point.
The spiral starts early and never stops—you keep adding, adding, adding, getting more rotation until the maximum rotation point. This is the difficult thing for beginners to understand.
Braking and Speed Carry Analysis
Looking at the inputs: the driver brakes on a straight line (good, not creeping) and stays pretty close to the white line. He starts to turn where he's supposed to initiate the arc (also good), but he's braking too much and too early. Then he releases the brake and is already accelerating.
The problem: if we're getting back on throttle, the speed should go down up to the maximum rotation point. At only 5% throttle, the speed is still going down (74, 73 kilometers per hour), and then finally the driver starts to accelerate more—enough to maintain 74, then the speed comes up a little bit.
We really want that increasing rotation all the way to the maximum rotation point. Technically the speed graph looks right because minimum speed was reached at the correct point, but having to accelerate so early and wait, wait, wait while maintaining very low speed means the driver could have carried more speed from earlier in the corner.
Better approach:
Instead of braking hard early, brake later and softer
Carry more energy through the corner
Force the braking to continue longer
Still arrive at the minimum speed point at 74 km/h, but win half a second to one second of lap time
Throttle Hold and Understeer
After braking early, the driver holds a very tiny amount of throttle, which makes the balance comfortable. This is literally what we teach when it comes to inducing understeer, but this understeer is not the way you're going to drive fast—it's the way you're going to understand the grip.
After understanding understeer, you have to clean it up and make sure the car rotates as much as possible when you're comfortable with it. The progression is:
Learn how to induce understeer
Learn how to induce oversteer
Find the middle point and try to rotate the car as much as possible without losing the rear
In this corner: too early braking, then coast and hold the throttle, creating a waiting moment. The driver was on throttle so early while steering was still increasing—this shows that at the maximum rotation point you're maybe on the good limit, but all the earlier area was under limit because there wasn't enough steering and not enough throttle. Obviously you could not have accelerated because the corner radius was too close, but this was all caused by braking too early instead of braking less and carrying that all the way to the maximum steering point.
Subsequent Corners: Pattern Recognition
Left-Hander and Trail Braking
The left-hander is a consequence of all the issues from the previous corner. The braking here is better and makes more sense than turn one—there is trailing, but a little bit too much trailing.
What happened: the driver trailed and then suddenly the car is turning more than necessary, which forces early acceleration. This is bouncing off the apex. We are bouncing off the apex because the trail was too heavy. The driver trailed heavily and then immediately had to accelerate, making "this part too fat."
Better approach: start to release a little bit earlier to carry a little bit more speed and not have the car go unnecessarily to that point. Instead of bouncing, go around that part and don't get stuck before hitting the curb.
Trail Braking Purpose
Too much trailing here. Trail only enough. Why do we trail? Because you want to turn the car. If you're already getting the rotation, let go—release the brakes, because trailing costs you speed. You're paying the price; you're paying minimum speed to be able to get that rotation.
If you don't need that rotation, you're almost literally wasting your speed with no reward.
Mid-Corner Rotation Issues
Up to the turn-in point, everything looks good. Then the problem appears: the driver adds throttle right when rotation is needed. As soon as this happens, the car doesn't want to turn. This completely prevents the rotation from happening because we're getting back on throttle too early.
Look at how long the driver has to hold it—the car doesn't want to turn, doesn't want to go faster. The speed is literally still going down, so that's not enough throttle to even contain the fact that the speed is going down, but that throttle is definitely severely preventing the rotation from happening. This costs a lot of lap time.
What we need: trail, keep turning, keep trailing, get to the maximum rotation point, and then get back on power. What happened instead: trail, then enter no-man's land just understeering forever. The throttle is causing this problem.
Over-Braking Pattern
Same problem appears again: too much brakes forces the use of throttle that early. This kind of controls the rotation—you're not going to hit the grass, but you're not using the rear tires. It's unnecessary.
The car was going to turn way more than needed, but the driver held the brakes so hard the car was overslowed. Now the driver can already get back on throttle, and even on the throttle that's supposed to cause understeer, they still were able to hit the apex. This means you can brake a lot less into this corner.
Key Takeaways and Recommendations
Trail Braking Technique
For this driver specifically, you really need to find the use of the little trail. This little trail is super important. If you learn how to combine this with the steering as the steering goes up, up, up, up, up, and you're combining that to make this feel good, you have to carry enough speed.
If you brake too hard and can already go on throttle, that means you're way too slow. We want to be trailing. We want to carry more speed so that the trail braking is necessary to turn the car.
If you're too slow: no need for trail braking
If you're fast without trail braking: you understeer and go off
If you're fast with trail braking: you need the trail braking to stay on the line and get the rotation that's necessary
That's how you find the lap time and carry more speed into the corner in the first place.
Summary of Issues
This case study reveals lots of little things. This car will definitely be perfect for developing these areas, and these issues are likely present in other cars—this car just reveals them more.
The most important thing is the mid-corner rotation. Look for the mid-corner rotation. You need to continuously get the car to turn and need that rotation by:
Carrying a little bit more speed
Dealing with the entry oversteer
Mid-corner: turning the steering more
Using that one to ten percent brakes
Feeling that point before you get into the shoot phase
Point so that you can shoot. More laps, more laps, more laps—practice these concepts consistently.
Other Lessons