Veloce Raptor

Yes

AdamBrouillard

I'm sure you are not the only one feeling the confusion. It's hard to get to the right answer when you are comparing the benefits of early/less braking to late, hard braking or any other variations like these. Earlier/later than what? Harder/softer than what? Faster/slower turn-in than what?

These kind of suggestions of different techniques often come from circumstance based situations. Is the track bumpy or smooth? Stiff or soft car? Loose or tight handling? You still run into the same problem though. How bumpy? How stiff? How loose?

Instead, we want to go directly to the goal we are actually trying to accomplish. Let's just take straight line braking as an example as the goal is easy to understand. Maximum g in the opposite direction to where we are going. This basically boils down to using as much brakes a possible to keep the tire as close to the limit as possible. All of the previously mentioned elements like bumps and suspension setup, as well as a ton of other things will influence how quickly we can do this. It can be useful to know the basic influence of these elements for the first few times you enter a new corner as they can help guide you, but in the end it doesn't matter from the driver's perspective. We're simply trying to maximize that force by using as much tire as possible at every instant.

So the real question is not how fast or slow or soft or what have you do you use the brakes based on the circumstances. The question is simply what should the driver focus on doing to maximize the tire force pushing them directly backwards. What car control cue are they using to tell them how much brakes to use at every instant? Listening for tire lockup? Something else?

Although the physics get a bit more complex, the entire corner follows this exact same pattern. What is your ultimate goal at every instant in the corner and what car control cue/s are you paying attention to to guide your driver inputs?

mark kibort

Those "words" work. to slow the car at the maximum rate, you are going to need to do it hard and short. (The opposite is needed for other activities haha )


Since we are trying to save words, but also get the point across with the right vernacular..... i want to make a point that if the above is taken literally, this is not what optimizes approach braking. the reason is , as we all know, with max decel rates comes more weight transfer... so , we want to maximize decel rates, and with this comes dramatic weight transfer which is ideal in most cases. i think your point (and correct me if im wrong) is that at the point you are transitioning from braking to not braking in the second stage of the turn, how and where you release brakes alows for better cornering capability. I think the point is TOO late of braking (trail braking), is unbalanced, traveling faster, but not optimal, where a car that might have slowed further, released brakes, and now has better balance on all 4 tires (specifically longitudinally) , will be able to have higher cornering speeds .

so to break it up into 4 segments for each turn:

1. Straight line threshold braking . 100% capability, dont spike the application to avoid lockup before weight transfer, done right this will result in max weight transfer
2. Turn in braking (trail brake). slightly les braking , that progressively gets softer as you approach apex. which also includes timing of brake release.
3. Corning around the apex. max cornering speed /forces
4. Exit throttle, weight transfer to the rear on acceleration and release of steering input

hf1

This thread makes me think that I need to work on #1. I use the brakes mostly for getting the weight distribution the way I want it, given the car's set-up and the available grip at the four corners. Basically, to get the car 'dancing' to the apex and out of the turn. Decreasing the speed is only secondary in my mind as I approach a corner. The comments here and the above four points suggest that BOTH decreasing the speed AND adjusting the balance are equally important -- the latter quickly following the former. I think I'm ok with the brake release ('dancing', trail-braking) part, but probably not aggressive (and not late) enough with the brake initiation part.

Maybe this is because with a low HP car (SPB) 100% braking is required only after the very long straights. In the rest of the corners even the shortest 100% (threshold) brake stab would simply slow down the car too much.

mark kibort

I think all cars face the same control challenge when driven to the limit. the only difference with the lower HP cars, is what you said, only (or mostly) the high speed straights to slow turns, require 100% braking. the challenge is not going too late, where your entrance speed is so great , you miss the optimal release zone. (trying to turn a car that is not unbalanced) or brake too early and end up with a constant speed from turn in to exit (discussed earlier).
Watching laguna track video, you can clearly see that turn 2, 3, 5, 8, 10, 11 are the only times where 100% braking is required. the others like 4, 6, 9 are turns where its a quick stab, to scrub speed and set the car and release.
does it change for a low HP car? sure, maybe remove turn 3 and 10 from that group of 100% braking. (to your point)

hf1

I guess, the main question is this: Assuming that the entry speed and the turn are such that some (even minimal) period of threshold (100%) braking could be applied without slowing down too much, would that ALWAYS be preferable to a longer period of sub-threshold braking? It seems like Kibort and Coach say 'yes', VR says 'no'.

One advantage of 'longer, sub-threshold' braking (vs. 'short 100% threshold stab') I can think of would be exploration of, and adaptation to changing conditions (track temp, weather, tire heat/pressure/wear, etc.). A 'short, 100% threshold' brake stab requires pin-point execution at the exact optimal brake mark, with the exact brake pressure and time-length for max performance, but if conditions are changing, then the optimal brake mark, pressure, and time-length would also have to change. A 'longer, sub-threshold' brake allows for a wider margin of exploration, more adjustability, with a smaller performance penalty for missing the (changing) optimal brake mark, pressure, and time-length. It's much easier to over/under brake with a 'short, threshold stab' vs. 'longer, sub-threshold' brake. Thoughts?

ProCoach

Folks can debate theoreticals all the time. I recognize Adam's careful and studious approach, but deal in reality, practice and execution, along with a thousand variables...

What I share with the people I work with is that anything less than optimal or near-limit performance is a subjective value execution, one that varies and injects MORE uncertainty, inconsistency and risk, rather than less.

Braking is one of those performances that must be as consistent and repeatable as possible.

This way, you can not only JUST vary the length of time that you slow to match the desired speed delta (as opposed to adding a variable slowing rate that is, well, variable), but also accurately and repeatedly define the End-of-Braking point and establish with certainty and without fear or anxiety, the application point.

My experience is that people brake to what THEY think the car is capable of, NOT what it IS capable of. This is why threshold braking is a fundamental skill execution taught at every major school worldwide, BEFORE moving on to other skills. Ecole Winfield, Jim Russell, Skip Barber, Bertil Roos, Bondurant, Allen Berg, you name it, the curriculum, and it's place in it, is the same.

The problem I have had working with a variety of clients is that when they master the execution, they retain their early application point and overslow. Then, I have to ask them to "walk the braking zone in" while retaining the high, level, deceleration rate to the turn in... Hard to do when the sphincter sensor is off the scale.

But this IS the defining difference when reviewing data from folks like Pat Long, Eric Curren, Tom Long, Mike Skeen, Jeroen Bleekemolen, Johannes van Overbeek, Romain Grosjean, Jacques Villenueve and others. These drivers are extremely efficient in their use of the car and the tire capability. I believe club level and DE drivers can benefit from adopting a similar approach, if they are interested in progressing.

I am measuring often the end result. Either through review of data, primarily gSum, or real time through MoTeC's SLM or this new Apex DDC, it's possible to calibrate your butt to more safely and incrementally approach "the limit" and more consistently, too.

I have sold nearly ten of these really cool tools: https://www.apextrackcoach.com/ Basically using AI to constantly build a model (taking into account relative grip levels, topography and aero) and a complex and powerful IMU to show real-time how much of the tire grip you're using. I really like them and have them in stock.

AdamBrouillard

Missing your ideal entry line has a big time penalty so pushing your braking deeper than you are absolutely sure you can handle is generally not advisable if your goal is minimal laptime. Beyond that it's just about how well you know the grip level and your level of car control skill. If you are sure you can make the apex from a certain braking point, there really shouldn't be any reason to brake earlier if your goal is minimal laptime.

If you aren't sure you can make the apex from that brake point or you can only do it every once in awhile then it's probably not a good point to use for a race, but might be a good one to do in testing when you are working on your skills. Going even later can be helpful too when training. To really push yourself I often recommend to intentionally brake late for an imaginary apex a few feet outside the real one. If you can still make the real apex from this later braking point you'll know you were leaving some time on the table.

ProCoach

To your first observation, agreed!

To your second, I think that exercise encourages a multiplicity of sins, including non-optimal visual tracking, counter-productive visualization of the actual apex and requires a steering amplitude input technique that is not compatible with the rise in entry speed due to the "intentional brake late," OR good practice. The bottom line is that it's hard to ADD steering when you're over the limit! No "spiral" possible!

I recommend people look for an imaginary apex INSIDE the real one, then if they have to do a correction, they can open...

IF you are consistent in your braking deceleration, as measured in longitudinal g's, and you can bridge the sustained longitudinal g to the sustained lateral g, as evidenced in the gSum strip chart, you're going to maximize all aspects of braking, transition and cornering.

sbelles

All of this discussion revolves around an optimal line through a corner. In a race, as often as not, you find yourself on alternate lines and therefore alternate brake points and even pressures. The thing that I see new racers have the most trouble with is going as fast as possible when they are not on the optimal line.

Beantown Kman

^^^This is the essence of what this whole thread boils down to. The only critical element that is missing is the need to execute this technique while placing the car on the line that will allow you to get to WOT the soonest.

But, as VR and others understand, executing Pro Coach's recommended style of corner entry is very difficult for most drivers and requires tremendous precision. Giving up a little efficiency in order to maintain a more stable platform usually leads to making fewer mistakes and the result for most people will be lower lap times, albeit perhaps not the lowest lap times possible.

hf1

Agreed.

What if braking slightly earlier and with slightly less pressure would upset the car less, bring it to the desired balance (weight distribution) faster and allow for a higher speed (Vmin) through the turn? Is the consensus that a shorter (hence, later) 100% threshold brake stab is preferable to this in every situation, without exception?

Manifold

Here are some educational and inspiring videos as an antidote to all of the theoretical talk:

mark kibort

The confusion is that weight transfer is "upsetting the car". under threshold braking, the weight transfer is a fact of deceleration, but allows for more front tire forces, to initiate a turn in at a higher rate of speed, as well as allowing for continued deceleration before the release of the brakes and the return of an optimally balanced chassis though the highest turning force area of the turn.
In other words, you can hit that max lateral force both ways (with a high decel rate and a lower decel rate) the higher decel rate will allow for faster segment times of the prior straight plus the turn . (assuming the same exit speed from the turn)

As i mentioned, the 100% threshold brake stab is not appropriate at every turn, only on those that can allow for the amount of time and distance, needed to apply a 100% brake /tire decel application. my example of Laguna Seca's turns 4, 6, 9 was an example of quick stabs where 100% brake application is not possible or required in most cases. these turns are similar to those at other tracks. most are called things like " the kink" , or the entrances to some "carocels", etc.

hf1