I have also wondered about this. My guess is that most racers break hard just before the turn and downshift after the turn, whereas the heel and toe method is for downshifting before the corner. - steve 5-24-2012 8:50 pm [add a comment]
Yes, the video is accurate. His throttle technique accelerating out of corners is odd. It goes against conventional wisdom to a) be smooth and b) never apply more throttle than you know you can maintain (always increasing, or at least non-decreasing application). He's pretty stabby on the gas. Seems to work for him, but he's a god.
In racing, it's important to be in the proper gear before starting to accelerate. In a typical corner, the car touches the inside of the track (that point of contact is called the apex) somewhere after the geometric mid-point. Throttle application starts somewhere before that mid-point.
Gear shifts are ideally done in a straight line, to avoid problems due to changing power delivery on the drive wheels. This is especially true with downshifts. A blown downshift can chirp the tires (or worse). If the car is in the middle of the corner, this can lead to a spin.
Put that all together, and the best time to downshift is during braking (which is also ideally done in a straight line). A perfect downshift takes two feet, one to operate the clutch and one to blip the throttle so the engine speed and wheel speed are perfectly matched. Lack of a rev match will wear out the clutch, lock up the drive wheels or both. The problem with using two feet to do the perfect downshift is there are three pedals to be operated -- because all this is going on during braking.
In a transmission without synchromesh (e.g. a true racing transmission, or a semi), each downshift requires two clutch operations. Putting this all together results in the heel-toe double clutch downshift in the braking zone.
Adding to all the excitement is the fact that brake release technique is a critical skill that separates the sort of fast from the really fast. This is truly a fine motor control skill ... with the feet ... while doing the three pedals with two feet thing.
In my race this past weekend, my clutch began to fail. It wouldn't fully disengage -- meaning when the clutch pedal was to the floor, the engine was still connected to the transmission. The failing clutch lead to the synchromesh getting chewed up. My co-driver has such excellent technique, he was able to adapt and continue.
I, on the other hand, don't have the same level of skill. Eventually, I gave up on shifting, and focused on driving a better lap with the car in one gear. Slow corners followed by long straights were especially painful. Somehow I adapted, and did my fastest laps ever on that track configuration.
- mark 5-25-2012 8:03 am [add a comment]
The upside of having a clutch/transmission problem is that I was able to really focus on my braking technique. Without all the fancy foot work, I had a lot more finesse going on. The trick is to maintain that finesse while doing the footwork.
Initial brake application can be pretty brutal, especially in a car with ABS. In most cars, the ABS is worse than a really good driver, but ABS serves as a safety net. By preventing lockup, it prevents flat spotting tires, which can ruin them, and it prevents the lousy deceleration of a locked up tire. Anyway, the initial brake is the hardest brake, and requires less finesse. Then release starts almost immediately.
Are you familiar with the "limousine stop"? The driver gradually reduces brake pressure as the vehicle slows. As it comes to a stop, a passenger will be hard pressed to detect the exact moment the vehicle stops without looking out the window. Braking in racing is sort of like that. But instead of 35 mph to 0 mph, the speed change may be 115 mph to 45 mph. But the goal is to make that final release of the brake pedal almost undetectable (other than brake lights).
Limousine-stop-smoothness combined with mountain-dancing-on-three-pedals. - mark 5-25-2012 3:39 pm [add a comment]
If the gear change is done right before major application of the throttle (somewhere in the white/purple range around the apex), the car could spin. The car still has a lot of lateral load, and a gear shift upsets the car enough that spinning is a possibility.
If the driver waits until the car is completely straight (way off to the top right) before downshifting, then during the whole purple region the car is bogging in the wrong gear. (Great way to get passed before the next corner.) So the driver downshifts (using heel-toe to blip the throttle) in the orangey-red portion. This sets up the car for the best launch out of the corner.
The "Trail Braking -- (advanced)" indicates the gradual brake release I mentioned. With trail braking, the initial brake can actually be a lot later (since the release is a lot later), and the weight is smoothly transitioned from the nose of the car to the side of the car. The better balance from a smooth weight transition allows a higher corner entry speed.
For that type of corner, the trail braking graphic is a bit off. The orangey-red should be a gradient, since release will initiate while the car is still straight, Full release would likely happen a bit sooner than indicated. Excessive trail braking can spin the car too -- which is why the starting point is always "brake in a straight line." - mark 5-26-2012 12:31 am [add a comment]
Una mas ...
The video below is from Monaco last year. The clutches are operated by computer in the current F1 car, but you can see in the telemetry that the gears are counting down while the brakes are on.
When I compare my driving to the fast people I know, I can aspire to reach their level. As a friend says when I get close to the performance of a fast semi-pro, "You may not be at that level, but at least you're playing the same sport."
- jim 5-24-2012 8:26 pm
I have also wondered about this. My guess is that most racers break hard just before the turn and downshift after the turn, whereas the heel and toe method is for downshifting before the corner.
- steve 5-24-2012 8:50 pm [add a comment]
Yes, the video is accurate. His throttle technique accelerating out of corners is odd. It goes against conventional wisdom to a) be smooth and b) never apply more throttle than you know you can maintain (always increasing, or at least non-decreasing application). He's pretty stabby on the gas. Seems to work for him, but he's a god.
In racing, it's important to be in the proper gear before starting to accelerate. In a typical corner, the car touches the inside of the track (that point of contact is called the apex) somewhere after the geometric mid-point. Throttle application starts somewhere before that mid-point.
Gear shifts are ideally done in a straight line, to avoid problems due to changing power delivery on the drive wheels. This is especially true with downshifts. A blown downshift can chirp the tires (or worse). If the car is in the middle of the corner, this can lead to a spin.
Put that all together, and the best time to downshift is during braking (which is also ideally done in a straight line). A perfect downshift takes two feet, one to operate the clutch and one to blip the throttle so the engine speed and wheel speed are perfectly matched. Lack of a rev match will wear out the clutch, lock up the drive wheels or both. The problem with using two feet to do the perfect downshift is there are three pedals to be operated -- because all this is going on during braking.
In a transmission without synchromesh (e.g. a true racing transmission, or a semi), each downshift requires two clutch operations. Putting this all together results in the heel-toe double clutch downshift in the braking zone.
Adding to all the excitement is the fact that brake release technique is a critical skill that separates the sort of fast from the really fast. This is truly a fine motor control skill ... with the feet ... while doing the three pedals with two feet thing.
In my race this past weekend, my clutch began to fail. It wouldn't fully disengage -- meaning when the clutch pedal was to the floor, the engine was still connected to the transmission. The failing clutch lead to the synchromesh getting chewed up. My co-driver has such excellent technique, he was able to adapt and continue.
I, on the other hand, don't have the same level of skill. Eventually, I gave up on shifting, and focused on driving a better lap with the car in one gear. Slow corners followed by long straights were especially painful. Somehow I adapted, and did my fastest laps ever on that track configuration.
- mark 5-25-2012 8:03 am [add a comment]
The upside of having a clutch/transmission problem is that I was able to really focus on my braking technique. Without all the fancy foot work, I had a lot more finesse going on. The trick is to maintain that finesse while doing the footwork.
Initial brake application can be pretty brutal, especially in a car with ABS. In most cars, the ABS is worse than a really good driver, but ABS serves as a safety net. By preventing lockup, it prevents flat spotting tires, which can ruin them, and it prevents the lousy deceleration of a locked up tire. Anyway, the initial brake is the hardest brake, and requires less finesse. Then release starts almost immediately.
Are you familiar with the "limousine stop"? The driver gradually reduces brake pressure as the vehicle slows. As it comes to a stop, a passenger will be hard pressed to detect the exact moment the vehicle stops without looking out the window. Braking in racing is sort of like that. But instead of 35 mph to 0 mph, the speed change may be 115 mph to 45 mph. But the goal is to make that final release of the brake pedal almost undetectable (other than brake lights).
Limousine-stop-smoothness combined with mountain-dancing-on-three-pedals.
- mark 5-25-2012 3:39 pm [add a comment]
This diagram gives an overview.
If the gear change is done right before major application of the throttle (somewhere in the white/purple range around the apex), the car could spin. The car still has a lot of lateral load, and a gear shift upsets the car enough that spinning is a possibility.
If the driver waits until the car is completely straight (way off to the top right) before downshifting, then during the whole purple region the car is bogging in the wrong gear. (Great way to get passed before the next corner.) So the driver downshifts (using heel-toe to blip the throttle) in the orangey-red portion. This sets up the car for the best launch out of the corner.
The "Trail Braking -- (advanced)" indicates the gradual brake release I mentioned. With trail braking, the initial brake can actually be a lot later (since the release is a lot later), and the weight is smoothly transitioned from the nose of the car to the side of the car. The better balance from a smooth weight transition allows a higher corner entry speed.
For that type of corner, the trail braking graphic is a bit off. The orangey-red should be a gradient, since release will initiate while the car is still straight, Full release would likely happen a bit sooner than indicated. Excessive trail braking can spin the car too -- which is why the starting point is always "brake in a straight line."
- mark 5-26-2012 12:31 am [add a comment]
Una mas ...
The video below is from Monaco last year. The clutches are operated by computer in the current F1 car, but you can see in the telemetry that the gears are counting down while the brakes are on.
When I compare my driving to the fast people I know, I can aspire to reach their level. As a friend says when I get close to the performance of a fast semi-pro, "You may not be at that level, but at least you're playing the same sport."
This is something completely different.
- mark 5-26-2012 1:23 am [add a comment]