80 replies to this topic

[The Runner]

Do modern F1 drivers trailbrake??

[Liam]

Depends on what you call trail braking.
I'd take it to mean staying on the brakes a bit as you turn into the corner, and as far as I'm aware, some of the modern F1 drivers do that.
If you mean the GPL technique of using a bit of throttle as you brake, I rather doubt they do. I believe some drivers did that a little now and then, but in real cars it was never done at every corner on every lap. Tyre and brake wear as well as brake temps and fade would mean it would not work in a real car. That it works in gpl is due to GPL not modelling tyre wear and brake fade.

[Buford]

I did it in Sprint Cars (both throttle and brake at the same time) but not both throttle and brake at the same time in sports cars. I did brake way deep into the corner while turning and few people did then (1970's) In fact I got into an argument-discussion as to whether it was even effective with my instructors at the Jim Russell school where I went in 1977 after 7 years of racing. They taught the brake in a straight line, even throttle to the apex, then accelerate technique and still do I think. Since I didn't do that, and I was obviously fast, we talked about it alot. We went out to a pub one night and they were picking my brain even though I was a student. They knew I was fast, but they did not think it was teachable or even sane what I was doing. They weren't even clear on what it was other than I went sideways (somewhat, not fully) where they wanted me straight, yet the stop watch did not lie.

I told them about Mark Donahue's book, "The Unfair Advantage" I had just read and how he explained why he was fast and that was what I was doing too even though I had just read the book. I had been doing it for years but he finally explained what I was doing and why I could gain so much under braking yet not lose time on corner exit. They simply did not believe it, but since Donahue had said it they were going to run out and get the book.

A few weeks later I got a letter. They said they had read the book, they had learned how to do it, and they agreed it was faster. But they said they could never teach it because it left no margin for error and the students would wad up their cars. But they said it was the first time they had learned something from one of their students.

But that was not throttle and brake at the same time. That was braking very late, turning while still going too fast to make the corner and still hard on the brakes, going into a slide, and then at the last instant as it started to spin, nailing the last downshift, dumping the clutch and nailing the power and snapping the car straight on full throttle to exit the corner. Donahue described it as using the friction circle. Transferring braking forces into turning forces into acceleration forces without losing any energy. I fell into doing it from a sense of feel and starting out in Mini Coopers.

How they drive modern F1 cars I don't know because we didn't have wings, or ground effects or sticky tires.

[cheesy poofs]

Originally posted by Buford

That was braking very late, turning while still going too fast to make the corner and still hard on the brakes, going into a slide, and then at the last instant as it started to spin, nailing the last downshift, dumping the clutch and nailing the power and snapping the car straight on full throttle to exit the corner. Donahue described it as using the friction circle. Transferring braking forces into turning forces into acceleration forces without losing any energy.

Several years ago in F1 Racing magazine, I read an intesting article on this subject in Peter Windsor's column. Basically, He was talking about drivers who turned-in early vs. others who had a more classic line. All of this involving the "friction circle" . Several current drivers ( JV, D. Hill, etc... ) were in total disagreement in what Windsor was saying. Several months passed before the subject came up again but, this time, in a full article with pictures to prove the point.
I thought this was a facinating subject. Here you had an explanation on cornering / braking techniques and drivers who were puzzled by the whole thing !! Different techniques, yet, same lap times. According to Windsor, the best driver to maximize the use of the "friction circle" was Micheal Schumacher. We have all heard of stories of MS going much faster that others into corners.
This helped me understand why the man ( BTW, not my favorite driver ) is so different than others.

Funny enough, when I spoke to friends who race...none of them had ever heard about this ?

[karlth]

Originally posted by Liam
Depends on what you call trail braking.
I'd take it to mean staying on the brakes a bit as you turn into the corner, and as far as I'm aware, some of the modern F1 drivers do that.
If you mean the GPL technique of using a bit of throttle as you brake, I rather doubt they do. I believe some drivers did that a little now and then, but in real cars it was never done at every corner on every lap. Tyre and brake wear as well as brake temps and fade would mean it would not work in a real car. That it works in gpl is due to GPL not modelling tyre wear and brake fade.

Jenson Button did use the throttle when braking for a corner simply to stabilize the car, a well
known kart technique. He stopped it when he found out he used a lot more fuel than Fisichella
and always had to pit a few laps earlier. Trulli might still do it though based on his extensive kart
background and weak race pace.

All drivers use trail braking, i.e. easing of the brakes into the corner, sometimes. It depends
on the type of corner. I doubt many drivers would use a lot of trail braking into a 180 degree
hairpin(La Source) while not trail braking into a wide corner(Parabolica) is probably very inefficient.

[Wolf]

That technique of braking well into the corner (almost up to the apex) was, AFAIK Moss' way of gaining 'unfair advantage' when GP was turned into Coupe d'Petit Cylinders in '61, a thing he thought to work against his superiority...

[Buford]

Several current drivers ( JV, D. Hill, etc... ) were in total disagreement in what Windsor was saying.
----------------------------

Hee Hee - so it is still a contoversial subject today! So you can imagine what it was in 1977. Donahue was the first to use the term "Friction Circle." He discovered it because they used to take their Trans Am and Can Am cars to skid pads and nobody else did that and he learned to feel the absolute limit of tire adhesion in a turning circle. He then learned how to brake right up to that limit and accelerate away from that limit.

I was definately doing something similar. I drove Mini Coopers and I had bad brakes at least in the beginning. I had to learn how to get slowed down because I was always in too deep. I learned the feel of the tires at maximum adhesion and I had to go sideways to scruff off speed. And I had raced quarter midgets for 9 years as a kid, so going sideways was not scarey to me. Because it was front wheel drive, I could stand on the power before I was fully slowed down enough and it would snap straight. I had my car totally stiff and a couple guys who drove it said it was undriveable. But it worked for me because I wanted to be loose.

When I switched to rear wheel drive, I used a modified technique. Not as sideways, and not as radical because I did not have the front wheels to pull me out of trouble. But still it was in the being able to feel the tires where I could get some gain. Not everybody can do it. And it is only a little faster. But it is faster. And I didn't mention it before, but part of the technique as you note is turning in early because you are sliding and going too fast and when you end the slide you need to be pointed to leave the corner.

You accelerate away at the exact same point you would if you were using the traditional technique. The difference is you are in big trouble every single corner and you are on the verge of spinning at the same point everybody else is stable and all squatted down on their suspensions ready to accelerate. So you have to get it right every single time. There is no margin for error. The gain is in the late braking and the turn in area. The acceletation area away from the turn is the same.

I suspect this is part of Schumakers secret. But with today's tires and downforce, we do not see the sideways part. Yet it is there, it is not noticeable because it happens only to a small degree more than the other guys. He is probably getting everything out of the tires under braking, turn in, and acceleration and the other guys are leaving a little energy wasted. A little on every corner adds up to a lot at the end of every lap.

[karlth]

As a side note trail braking is probably a more common technique in the hands of the the demonic
late brakers like Mansell and the Schumacher brothers than the classical drivers like Piquet,
Montoya and Prost.

[karlth]

Autosport analyzed Schumacher's driving style in their latest issue and it mostly agreed with Buford's comments.

It mentioned that his reflexes aren't especially good it's his feel for the grip that allows him to
slightly skid into the corner without losing the car. Normal drivers have to either use the classical
method of slowing down and pointing the car into the right direction out of the corner and then
throttling away or going very deep and being slow out due to the time needed to correct the car.
Schumacher on the other hand throws the car into the corner and when it is time to accelerate he
is pointing in the right direction while lesser drivers are still stabilizing their cars.

I highly recommend a video of Schumacher's qualifying lap at Sepang last year as a demonstration
of his technique.

[rdrcr]

Not much to add... as Buford has it just about covered.

I think that perhaps several drivers may use trailbraking in certain circumstances, but as a method of driving, as Buford so aptly states, there is zero margin for error and thus with all of the aids in F1 today, many would chose not to employ this tactic.

Schumacher on the other hand may have this circus trick down pat.

Good points as well Karth, Trailbraking is often used in Karting as maintaining speed is of the utmost importance, interesting to read that Button dropped his technique because of fuel concerns.

[fines]

Coincidentally, I use a similar technique when playing computer games (Grand Prix 3 atm). I came upon this rather instinctively, mainly because I always use keyboard steering. The bottom line, I crash rather often but am usually a lot faster than the AI guys... Apologies if this is rather inappropriate, but I don't have real racing experience (apart from a few hours racing karts, which didn't have enough power to perform such deeds...)

[fines]

Originally posted by karlth
As a side note trail braking is probably a more common technique in the hands of the the demonic
late brakers like Mansell and the Schumacher brothers than the classical drivers like Piquet,
Montoya and Prost.

I really don't understand this, because Prost and Mansell were the first ones I saw trail braking (apart from Freddie Spencer, that is!). They had a very similar driving technique! And really, I don't think they braked that much into the corner, but definitely carried the speed into the bend to scrub off during turn-in.

[cheesy poofs]

Some of you might remember this topic ( read this ) in another forum...

Have a good look at the first two graphs. It says a lot about the way MS drives fast.
On the first one, you can learly see that Herbert lift's off the throttle and uses minimal steering input while going much slower than Schumacher. Michael, on the other hand, only lifts off slightly and, in the process, achives a lot more speed than Herbert. See how MS is using the steering.
Very interesting...

Remember Barcelona a few years ago when Michael did half the race stuck in 5 or 6th gear ?
This is how he achived this: trailbraking and carry lots of speed into corners without losing to much time...

[silver]

If go through the topic where cheesy poofs' topic points you will also find articel Martin Brundle where he comparing Michael Schmacher's and Mika Hakkinen's driving styles.

They both are able to turn the nose of the car earlier to the direction of the next straight than most of the drivers. The difference is that Schumacher uses throttle to achieve that and Hakkinen uses brakes.

[SpamJet]

Where does engine braking fit into allof this?

[jhodges]

Originally posted by silver
They both are able to turn the nose of the car earlier to the direction of the next straight than most of the drivers. The difference is that Schumacher uses throttle to achieve that and Hakkinen uses brakes.

This is exactly the point, too. An F1 car is at maximum efficiency when travelling in a straight line. Obviously, slowing and turning vastly reduces the effect of aerodynamic downforce and ruins the wings & bodywork's interaction with the tires, so staying fast and straight would maximize these effects. Any driver who can point the car in the correct direction first should have an advantage.

I also thought that trailbraking was quite standard in the modern era.....especially since most drivers left-foot brake. I raced road bicycles for years and always had to try and "unlearn" trailbraking during descents. I always found it to be very instictive, not to mention a little comforting, to dab the brakes when my senses were screaming at me that I was nuts for entering a corner at high speed.

I would guess that an F1 pilot is a lot braver that I....

[DOHC]

Buford -- what is your opinion of Clark? Did he trailbrake? I remember reading a careful study of how Clark and Hill differed in styles in an F2 race in 1967. According to this, from the vantage point of a single, sharp corner, Hill braked early and turned in late and had the power on before reaching the apex. Clark on the other hand braked late and turned in on the brakes and was later on the power, although he appeared to carry more speed into the corner.

[The First MH]

This is all very interesting to a person like me, who has never had any actual racing experience. But I am left wondering what tail-braking does for tires? It seems to me, as a casual observer, that it would be a lot harder on tire wear than the more classic style mentioned by Karlth. Am I wrong?

[karlth]

Originally posted by The First MH
This is all very interesting to a person like me, who has never had any actual racing experience. But I am left wondering what tail-braking does for tires? It seems to me, as a casual observer, that it would be a lot harder on tire wear than the more classic style mentioned by Karlth. Am I wrong?

No, you are correct. For example Barrichello who's driving style is not unsimilar to Montoya's is
easier on the tyres than his teammate.

[The First MH]

Thanks

[karlth]

Originally posted by The First MH
Thanks

An important point to note is that it is not the actual trail braking that is eating the tyres but the
slide into the corner.

[Ross Stonefeld]

We need more clear definitions. Trail braking isnt neccessarily sliding, and left foot braking isnt automatically braking with throttle

[karlth]

Originally posted by Ross Stonefeld
We need more clear definitions. Trail braking isnt neccessarily sliding

No but the way Michael does it is that he slides the rear of the car into the corner while trail braking.

[The First MH]

Been thinking - always a bad thing! If the gains of tailbraking outweigh tire degredation (in overall lap times) then why don't more drivers do it? Is it as simple as that, or is it that at some tracks tailbraking is better, and produces better results, whilst at other tracks it tends to benefit the more classical driver approach? IOW, is there a definitive way to say which is better?

[DOHC]

Originally posted by The First MH
Been thinking - always a bad thing! If the gains of tailbraking outweigh tire degredation (in overall lap times) then why don't more drivers do it? Is it as simple as that, or is it that at some tracks tailbraking is better, and produces better results, whilst at other tracks it tends to benefit the more classical driver approach? IOW, is there a definitive way to say which is better?

I think what Buford et al says is that it's a difficult driving style to master. After all, you have to keep forces on the very boundary of the friction circle all the time from braking, through cornering, to accelerating. If they don't teach it at racing school, or don't even master it there, I think one could fairly say that it's advanced-level driving. Perhaps it's what gives the best drivers their little extra edge?

[Arrow]

Originally posted by The First MH
Been thinking - always a bad thing! If the gains of tailbraking outweigh tire degredation (in overall lap times) then why don't more drivers do it? Is it as simple as that, or is it that at some tracks tailbraking is better, and produces better results, whilst at other tracks it tends to benefit the more classical driver approach? IOW, is there a definitive way to say which is better?

Its all about instinct.Some drivers are natural trailbrakers some are not and never will be.
Its like being left handed.
You cant help it.

[DOHC]

An additional difficulty is, I think, that in today's wing/aero cars, the diameter of the friction circle depends on the velocity. That should imply (and I guess here) that it is more difficult to master this type of driving than it was in non-winged cars.

I doubt that a monkey can drive today's cars on the edge -- some difficulties like manual gearchange are gone, but others have emerged. I don't think one can say that the old guys were better because they mastered things that today's drivers don't. Today's drivers master things the oldies didn't.

[The First MH]

very enlightening - thanks!

[Ross Stonefeld]

I think because of the reasons you listed the modern driver on average is *slightly* better than the old one, because they've done both. They've raced ultra stiff zero downforce karts, high roll grooved tire Formula Fords, high grip low power Formula 3s, and high grip high power F1s

[MPea3]

running rallies on gravel in RWD cars i woudl set the brake prop valve heavier to the rear and use the brakes into the corner to help get the back end out until i was ready to get back on the gas, but didn't use both the gas and brake at the same time.

with either FWD or 4WD, i would use the brake and the gas at the same time in most corners, trailbraking into the corner to get the attitude of the car setup, then getting HARD on the gas and using the brakes as needed to "pivot" the car in the corner as needed. that was much faster than pivoting the car by backing off and then getting back on the gas. that was difficult to learn, as when the (or truck) began to push, the natural inclination was to back off to induce oversteer, kind of like how the first tiem i went snorkling it was hard for me to put my face under water and breath.

but then again this was rallying and not on tarmac...

[Ross Stonefeld]

In the Audi (first car where I had cockpit adjustable brake bias) I fiddled with the brakes until I got even front and rear lockup, then went half a click to the rear. So id come in, use maximum braking efficiency and release them more or less in a straightline with me still coming off the pedal just as im turning in. The result, if done right, was just a bit of a tail slide going in. You know how sometimes the F1 guys lightly lock the inside wheel turning in? Well it was like that except rear lock up. So id just lightly flick into the corner and id gently get on the gas both to settle the rear and get the turbo spooling up as I approached the apex. The full throttle full boost and hold on, and hope I can catch the slide coming out because I didnt want to lift and kill my boost.

In the Formula Dodge I drive in the states
( http://www.fowlerrac...s/Daytona 2.jpg )

How you release the brake pedal is key. They're quite odd little cars. Lots and lots of chassis roll both side-to-side and front-rear and pretty skinny hard compound tires. So how you 'pop' off the brake gives you either a really violent turn in or a nice smooth one. The best case of this was a turn at Putnam park thats really quick but needs a slight speed adjustment. You come in and enter the turn about half way off the road and use a 6 or 7 strength brake pedal (on a scale of 1 to 10) to get your speed adjustment and from then on is the brake skill. If you use the brake too long, you have weight on the nose and the back end comes around. If you jump off the brake pedal, it snaps around too because even though you're off the brakes, the front suspension responds slowly so it still has the nose pushed down even though you're off the brakes, and instead of having your tires being used 70% for turning and 40% for braking, they suddenly go to 100% for turning and you get pretty sideways. So the ideal is to brake, and slowly relase the pedal adjusting to get the kind of rotation you want. It isnt helped by having a steering column between your feet preventing you from left foot braking, so the tendnecy of using one foot for both braking and throttle is to snap off the brakes as quickly as you can to minimise time spend getting on the gas.

[rdrcr]

Let's take it from the top....

Trail-braking is a subtle driving technique that allows for later braking and increased corner entry speed.

The classical technique is to complete braking before turn-in. This is a safer, easier technique for the driver because it separates traction management into two phases, braking and cornering, so the driver doesn't have to chew gum and walk at the same time, as it were.

With the trail-braking technique, the driver carries braking into the corner, gradually trailing off the brakes while winding in the steering. Since braking continues in the corner, it's possible to delay its onset in the preceding straight braking zone. Since it eliminates the sub-optimal moments between the ramp-down from braking and the ramp-up to limit cornering by overlapping them, entry speeds can be higher.

The combination of these two effects means that the advantage of later braking is carried through the first part of the corner. In many ways, this is the flip side to corner exit, where any speed advantage due to superior technique gets carried all the way down the ensuing straight. The magnitude of the trail-braking effect is much smaller, though: perhaps a car length or two for a typical corner. Done consistently, though, it can accumulate to many 1/10's over an entire course.

When I was taught to drive in the late '70's (at Moroso Park) not all the fast drivers used trail braking and instructors usually gave it at most a passing mention as an optional, advanced technique. The reason was probably a risk-benefit analysis:

it's a small effect compared to the big-picture basics, like carrying speed out of a corner, that everyone must learn early on. It was difficult to learn, so why burden new students with it? And, mistakes with it are ugly. Another reason may have been that my instructors hadn't got their butts kicked recently by a trail-braking driver. I'm guessing that it wasn't a commonplace technique back then, so one might drive a whole season of club racing without getting spanked by a trail braking driver. Since not everyone used it, not everyone had to develop the skill.

Nowadays, however, the general level of driving skill has increased to the point where it's no longer optional, unless you're content with fourth place.

As with most driving skills, it's difficult to get a feel for the limits without exceeding them from time to time. However, exceeding the limits at trail braking has some of the worst consequences one can invite on a race track, typically worse than those from mistakes at corner exit. It's definitely a big risk for a small effect, justified only because it accumulates.

Blowing it results in too high an entry speed. You get: inappropriate angular attitude in the corner
immediate probing of the understeer or oversteer characteristics of the car. Surprise, pop quiz on the driver's car-control skills, a missed apex and track-out points... a looming penalty cone, gravel trap, tyre barrier, concrete wall, tree, and anything else that can go wrong in a blown corner.

In Karting, you learn that trail braking is a vital technique that helps maintain momentum and reduces the need for downshifting to have that higher exit speed. Thus translating into more efficient driving.

However, the use of this trail braking trick gets pretty dicey with the increase of weight and mass.

With a high powered car, it can lull one into becoming a lazy driver. With a lot of power on tap, you can often make up for an overly conservative entry speed on the exit.

However, when the cars are equalized, as in sports racers, spec classes, showroom stock, or in a lot of Solo II car classes, trail braking takes a prominent role. It can be difficult to spot it as an issue in Solo II, where drivers are alone against the clock. All else being equal, a Solo II driver without trail braking may just find himself scratching his head wondering how in blazes the other drivers can be so much faster.

Go wheel-to-wheel on the track with equal cars, though, and the issue becomes instantly and visually obvious. You may be just as fast in the corner, coming out of the corner, down the straight. You may have perfect threshold braking. You may have perfect turn-in, apex and track out points. But that little extra later braking and entry speed will allow the trail-braker to take away several feet every corner. Corner after corner, lap after lap, your competition will gobble you up.

When I got my CSR, I was doing it the old-fashioned way: get the braking done in the braking zone and get your foot back on the gas pedal and up to neutral throttle before turn-in. That little tenth of a second or so where I'm coasting and they're still braking is the car-length they were taking out on me. Back in the pits, with my Pi read-out, I could see that data. I compared the charts to a couple of other racers and the results were obvious, I needed to pick up this trail braking trick if I was to get on pace with the top 3 or 4 guys.

[benrapp]

The other point with trail braking is that it gives you additional load on the front (turning) wheels, helping to neutralise understeer and get the car into the apex. Provided, as others have said, you can feel the point of ultimate rear-end adhesion, and that your use of the pedal is subtle, it allows both a higher entry speed and a higher minimum speed. I suspect most drivers use it only at specific bogey corners, like Graham Hill bend at Brands or Foulston's chicane at Oulton (where actively unbalancing the car seems the quickest way round, using the pendulum effect to force turn-in for the right-hander). It works especially well in a 911 where the heavy rearward weight bias means that front-end grip is at a premium, but both rear-end lateral grip and accelerative traction on exit are good. On the other hand, it bites you quickly if you overcook it.

I also think trail-braking is hard on your brakes, partly because it encourages you to brake later and deeper, but also because you stay on the brakes at partial pressure, soaking them in heat. I had a big crash at Oulton a month ago: I was running on borrowed treaded tyres having spent the earlier part of the day on slicks and was struggling to keep up with a couple of guys who had substantially better rubber. The only way to stay with them was to brake ultra late and trail brake everywhere to get the nose in, given the lack of grip from the tyres. My brakes went off (having done three quals and two races that day with no problems, and without excessive wear at the start) after about six laps and I lost them completely going into Shell. I have never seen marshalls run so fast.

Ah well, they tell me the car will be rebuilt by July...

[Buford]

First of all this was origianlly posted on the Nostolgia forum where there is a less combative atmosphere and I have frequently posted about events I was involved in, in the 50's through 80's era. I was not trying to come on the forum and tell everybody I know everything about driving, especially in today's cars. I was an upper middle level driver who never got the big break in a competitive car in any professional series. There were very few rides open for rookies and they did not want young wild men then like they do today. They wanted years of experience for the top rides. My experiences came in trying to get the experience that would get me one of the handful of paid professional rides, on merit. I did however drive every kind of car, open wheel, closed wheel, road courses, ovals, both dirt and paved, midgets, sprint cars, every kind of sports car and formula car, and stock cars. And I did get paid to race, at least part of the time, but never for a living. I just poured whatever I made back into more racing, and the travel and expenses to get there. But not at the very top level. So you can take my opinions and experiences with any number of grains of salt you wish and how it relates to today's cars, I do not know either.
-----------------------------------------------------------------

First of all we did not call it trail braking then. We did not call it anything because we did not know anything about it. I was fast from the very first driver school. But I flew off the road alot and almost flunked my first driver school. My personal instructor said I was the best guy he ever instructed, because in between the flying off I was running record laps, 3 seconds faster a lap than the guy who owned the car. Many of the other instructors thought I was someone who would kill myself very soon and was a danger to everybody out there. Both sides had a point.

But what I was doing was driving by feel and I was learning my own technique, which at the time, and for years later I did not realize was not also everybody else's technique. But what I did know is I could outbrake everybody (with reasonably equal cars and brakes). If I could get near them, I would simply wait until they braked, wherever it was, pull out, go inside, take their line away, throw it sideways (not as much as a Sprint Car but noticeably tail out) scare the hell out out them, and beat them to the apex, without sacrificing exit speed. I didn't know why I could do this and I didn't know why I was faster than anybody who ever drove the same car as me. I wrote it off to I simply wanted it worse. I took personal offense to anybody passing me. They were trying to steal from me everything I ever wanted and it made me furious. A controlled fury that required I pass them right back even if they were going to power back on the next straight because they had better power. It wasn't until I read Donahue's book after I had already raced a number of years, I first understood what I was doing the others weren't.

And because I thought I had a pro ride lined up I decided to go to the Russell School. Primarily to get an evaluation from them. I knew how to race. But I knew you can always learn more. And I thought maybe I could win their "Driver To Europe" program (which I almost did). So when I got there, I scared the hell out of them and I simply could not drive the way they wanted me to. I tried but the red light in my head that said "TOO SLOW - TOO SLOW" kept coming on all the time. So I just went back to driving the way I wanted, and they could clearly see I was not doing what they told me to, yet I was blowing away the lap times they knew were possible at each one of the rev limits. I was getting it all wrong, yet I was faster than I should be. So they were a combination frustrated and pissed off at me for failing to take instruction, yet at the same time fascinated by the fact I was so fast. The stop watch did not lie and so we talked about it for hours, even "off the clock" in the evening. This is the first time I became aware I was doing something different from the norm, more than just wanting it more than the other drivers I was racing with. The only reason they didn't discount me totally was the stop watch and I told them about Donahue's book which I had just read in the weeks prior to going to the school. Because of what Donahue wrote, and my descriptions to them of what I was doing, and the fact I was an experienced driver and an SCCA instructor myself, they did not necessarily think I was totally full of it. But they also did not understand it.
-------------------------------------------------

"Buford -- what is your opinion of Clark? Did he trailbrake?"

I only saw him on ovals (except once), Indy and Milwaukee so I cannot say what he was doing other than IMO he was the best I ever saw. But he made things look easy. From what everybody told me, I never made anything look easy. I looked out of control and in effect I was in the braking zone. I was intentionally going out of control to aid in slowing down, and then stopping it at the right moment. So I don't know about Clark. He was very smooth. Never seemed to have the car out of shape. I was always out of shape. Maybe he was just so superior he was doing something similar but so quickly we didn't see it.
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"later on the power, although he appeared to carry more speed into the corner."

IMO this would not be good. The whole thing is exit speed. My technique did not harm exit speed (when properly executed). It allowed later braking, and a faster inital turn in to the corner. Too fast in fact because I wasn't going to make the corner at that speed. I had to get down to the proper speed at the exact moment it was time to exit and that was the trick. Carrying more speed into the corner would be good. But not if it meant you were later on the throttle coming off I don't think. You would lose more down the next straight than the little you gained by late braking and turn in speed. But if you could do both, gain in braking and turning but not lose anything in exit, there was a speed gain there.

-----------------------------------
"But I am left wondering what tail-braking does for tires? It seems to me, as a casual observer, that it would be a lot harder on tire wear than the more classic style mentioned by Karlth. Am I wrong?"

With the tires we ran in the 1970s, basically rocks compared to the art gum erasers they use today, and the fact I did not run more than 1/2 hour to 1 hour races, it was not a factor. Today's tires that have only a few fast laps in them, and then go off, I would think it would be a problem with over stressing the tires.

------------------------------------------------

"An important point to note is that it is not the actual trail braking that is eating the tyres but the
slide into the corner"

Yes and that's why what I was doing and what Donahue describes was different than what people are calling trail braking today. It had an additional element. The braking while cornering was to brake later than the other guys and to get the car loose and actually beginning to spin. In the Mini I would violently crank the steering into the corner in addition to the braking while turning, to break it loose and slide, using tire scruff to help slow me down. The car was beginning a spin. A spin I hoped to stop at just the right time. In rear wheel drive I did not do as much of a violent snap of the wheel but I did tun in early and slide up to the point I was ready to get on it. And during the slide I was going thru the downshifts using engine braking to the fullest, to answer another question asked above. It was the final downshift at just the monent it was going to swap ends, at just the moment I wanted to exit, that stabalized the rear for an instant and then nailing the throttle snapped the car straight. That's the best I can decribe it. A controlled spin in the corner entrance that got stopped just before it became a real spin.
--------------------------------------------------

"Trail braking isnt neccessarily sliding, and left foot braking isnt automatically braking with throttle"

Yes it is a multi part approach to slowing down. Another thing was I didn't heel and toe. I was in way too much trouble trying to get slowed down and there wasn't time for niceities like than. I just banged it into the gear at the point my brain said the speed was slow enough in each gear that it would take. I was from the school of driving thought that my job was to go fast. Somebody else's job was to rebuild the gearbox.

-------------------------------------

"No but the way Michael does it is that he slides the rear of the car into the corner while trail braking."

If that is the case, then it explains to me, from my experience at lower levels of course, why he has them covered. It is faster that way if you can do it. If he can do it in modern cars, and the others can't or can't as well, that is the "circus tricK' that explains why he smokes them.
----------------------------------------------

"I think what Buford et al says is that it's a difficult driving style to master. After all, you have to keep forces on the very boundary of the friction circle all the time from braking, through cornering, to accelerating. If they don't teach it at racing school, or don't even master it there, I think one could fairly say that it's advanced-level driving. Perhaps it's what gives the best drivers their little extra edge?"

Exactly. I fell into it because my early car had terrible brakes and I did not have sense enough to
brake earlier to compensate. And I was used to sliding from my Quarter Midget days. But I flew off the track a lot, both when I was learning it and also in practice all through my career. Or at least spun a lot which was often intentional. When I realized I was not going to get slowed down. I would throw it into an intentional spin I could control rather than the uncontrolled spin it was getting ready to do. I used to go out to open parking lots late at night in the rain and snow and spin and spin before skedaddling before the cops came. I was not afraid of spins and I had situational awareness as to when I could stop a spin. So I spun a lot in practice, especially at new tracks, while I was learning the limit. This added to my reputation of being a crazy person, which had benifits on the track but not in the paddock. But when the race came I rarely spun. To learn how to do what I am describing, requires a lot of spinning. Most drivers cannot afford to spin a lot, or their car owners will get somebody who doesn't. And they don't realize that spinning can be good as a training method, as long as you don't hit something.
--------------------------------------

"An additional difficulty is, I think, that in today's wing/aero cars, the diameter of the friction circle depends on the velocity. That should imply (and I guess here) that it is more difficult to master this type of driving than it was in non-winged cars. "

I would think so too. We had hard tires that wanted to slide anyway.

------------------------------------

"with either FWD or 4WD, i would use the brake and the gas at the same time in most corners, trailbraking into the corner to get the attitude of the car setup, then getting HARD on the gas and using the brakes as needed to "pivot" the car in the corner as needed"

Yes, that is what I did in the Sprint Car on dirt. It was a pivot to adjust the attitude of the rear end.

[Buford]

"I also think trail-braking is hard on your brakes"

Oh yes. My crew was constantly amazed at how I used up brakes. We had to put in new pads for almost every session because there would not be enough left for a second full session. Most guys went 3 races on the same pads in similar cars.

[Williams]

This is what Clark said about his own driving style:

"It is considered that leaving your braking until the very last minute is important, and I would agree that it is important, but I would also say that it's where you take the brakes off that matters. Often, if I want to go through a corner quicker (Williams: interesting qualification that), I don't necessarily put the brakes on any later, but I might not put them on so hard and then I will let them off quicker. How you get led into the trap is by going deep into the corner and not braking until the last moment. During this you might arrive qucker, but you then tend to brake much harder than you need. It often happens that a driver when trying hard will set up a fast lap then, when told to ease off and relax, will find himself lapping just as quickly. This would appear to indicate that he was really overbraking and slowing the car more than he needed.

[Ricardo F1]

Originally posted by Buford
"I also think trail-braking is hard on your brakes"

Oh yes. My crew was constantly amazed at how I used up brakes. We had to put in new pads for almost every session because there would not be enough left for a second full session. Most guys went 3 races on the same pads in similar cars.

Which would explain why karting tracks pull out big signs when you do it to their karts!! I was a BIG trail-braker in karts . . .

[merlyn6]

Sorry I caught this thread late. My read on trail braking is similar to Donahue’s. You enter the braking zone; apply the brakes hard, then as you start easing off the brakes as you apply lock. The whole idea is to meet, but not exceed the tire’s limit of adhesion. When you reach the apex, or point of maximum lock, you will be completely off the brakes, as the tires are at their point of maximum lateral adhesion. You then feed the gas on as lock is released, once again just meting the tires maximum adhesion. When you are once again going straight, you are at full throttle.
Trail braking, as has been pointed out above, allows little room for error, as you will be on the limits of both lateral, and longitudinal adhesion. Trail braking usually involves an early turn in, which means you can carry more speed to the apex, thus maximizing the straight you are just leaving.
The use of trail braking is dependent on the corner, or more correctly what precedes and follows the corner. In the case of a long straight following I don’t trail brake, as the corner exit speed is not as high as it is in the case of straight line braking. This increased speed is too much of an advantage on the next straight, however if the corner follows a long straight, then trail braking might be advantageous. Trail braking works best when you have a series of corners, not connected by a long straight. It all depends on what part of the course you want to maximize. It’s a tool in a driver’s arsenal to be used when necessary. Left foot braking is a totally different thing, something which I have no experience with.

[DOHC]

Ross, Richard, Buford, Merlyn -- really great posts!

[ozf1]

Very interesting reading your story Buford, and rdrcr I thought you covered everything brilliantly. Infact all you guys really now your stuff. One of the best threads ive read.


Would it be fair to say that you can’t get anything for nothing, so if you have an early turn in and therefore trailbrake down to your minimum speed point, you must lose something at the exit?

Buford talked about rotating the car during the entry phase to improve the cars position for the exit. Wouldn't this be considered an additional technique to turning in early and therefore trail braking? For example MS often uses a fairly early turn in and Hakkinen used a slightly later turn in but both use a few degrees of rotation during the entry to help straighten the car for a better exit. I’m sure that Schumacher would be faster during the entry, but I’d also believe that Hak’s technique would allow a faster exit speed. Who would be faster would come down to the level of talent that each driver would apply to their technique and whos technique was most suitable to the particular circuit and conditions.

[howardt]

Originally posted by Buford
I was not trying to come on the forum and tell everybody I know everything about driving

Buford - I kneel down before you. Nothing but admiration for you.
I've never got closer than GP legends sim & track days (I asked a tutor about trailbraking - he laughed and said "First things first, son")
So there's no combative sarcasm from over here (Unless you want some ?)

A great driver and a great poster - thank you.

howardt

[merlyn6]

Originally posted by ozf1


Would it be fair to say that you can’t get anything for nothing, so if you have an early turn in and therefore trailbrake down to your minimum speed point, you must lose something at the exit?

Yes, because you have effectively moved the point of applying power further down the track when you trail brake, but you have been able to carry speed longer into the corner.

[Buford]

Originally posted by ozf1

"Very interesting reading your story Buford, and rdrcr I thought you covered everything brilliantly. Infact all you guys really now your stuff. One of the best threads ive read. "

Thanks for the nice comments and to DOHC also. Edit - Howardt too - BTW - I suck at GPL becasue I can't do any of what I was talking about in that game.
--------------------------------

"Would it be fair to say that you can’t get anything for nothing, so if you have an early turn in and therefore trailbrake down to your minimum speed point, you must lose something at the exit? "
------------------

Not if you do it right though as we have said, there is no margin for error and human beings are not errorless. Therefore there are times when you will indeed still be trying to get slowed down just to stay on the track because you blew it, and will not get on the power as soon as you should by a fraction of a second. I got to the point I never miscalculated enough to fly off the track anymore like I was doing early on. The worst mistake I would make in a race would be to have to go wide by a half car width or have to lift coming out and therefore blow the next straight and lose everything I may have gained and more. But I didn't do that very often.

I would kind of wing it in practice and I did spin a lot while I was feeling out the limit. But I had learned a lot of times I could go a tiny bit faster than I originally thought, so I would try it when nobody was behind me close. Most of the time I would be right and would white knuckle it through and that was now my new limit. Or I'd go a little off line and know I was right the first time and should go back to that. Sometimes I was way over the limit, and then I would pretty much do a deliberate spin I could control and go on after one or two loops. Probably twice at each new track I went to, two different corners or maybe even three I would establish the limit once and for all by spinning. But I never repeated the error. Once I had established the limit, I could pretty much turn out carbon copies from then on. How I don't know. My subconscious brain drove the car. I really didn't.

But I did also have the experience mentioned above that sometimes when my crew was telling me to slow down when I had a big lead, I tried to but I really did not slow down much at all. Even dropping the revs and thinking I was braking earlier, I still was pretty much doing the same things otherwise. Just not quite as frantically. So running the very limit all the time did probably mean I would slightly blow one or two corners and slowing down meant I was slightly slower on all of them except one but quicker there so the lap time remained the same. Sometimes my crew would be holding out an EZ sign and waving sledge hammers at me as I went by and I'd be giving them "I am" gestures and practically going to sleep and losing my concentration I was going so slow, but when they showed me my lap times, I wasn't even slowed down a full second a lap from when I was really pressing. So I don't know. All I do know is I could out brake everybody and that had serious gains in competition. Whether doing what I described actually was as effective all the time, even when I wasn't trying to pass somebody, I don't know. The Jim Russell people did think I was doing something that was effective though, after initial disbelief and actually kind of hostility to the idea it could be true. It just requires perfection all the time.
--------------------------------

"Buford talked about rotating the car during the entry phase to improve the cars position for the exit. Wouldn't this be considered an additional technique to turning in early and therefore trail braking? For example MS often uses a fairly early turn in and Hakkinen used a slightly later turn in but both use a few degrees of rotation during the entry to help straighten the car for a better exit. I’m sure that Schumacher would be faster during the entry, but I’d also believe that Hak’s technique would allow a faster exit speed. Who would be faster would come down to the level of talent that each driver would apply to their technique and whos technique was most suitable to the particular circuit and conditions. "
-----

Well as someone mentioned above, not every corner is the same and what comes after it makes a difference too. The corners that lead onto the longest straights are simply too important to blow trying to eek out a tenth of a second in the braking area. They would require a more of a conservative approach to make absolutely sure you would be able to accelerate at the earliest possible time. I drove those more conventionally. My descriptions were most appropriate to corners at the end of a long straight. The ones where I said I was in big trouble and it was touch and go as to whether I would get slowed down enough without having to lift coming out or going wide were most often at the end of the straight type corners, or any one requiring hard braking that had further twisty bits coming after them. Thinking back, I don't think I did that as much on the leading onto the straights corners. Those I was thinking "Exit Speed" in my brain and I did whatever it took to get exit speed.

But on the corners when I was really going in deep, I turned in early. Meaning that if I wasn't going to go into a slide I would miss the apex to the inside and drive into the grass (we didn't have curbs) before the turn if it went immediately where I was turning it. But because I was going too fast it would not turn then but begin to spin and I would ride out that initial part of the spin while frantically braking and downshifting and hanging the tail out to the point where I would stop it with the final gear change and accelerator. That spot would be at the exact same point I would have been at had I been driving conventionally and I was already pointed in the right direction when I got there. I just turned early and arrived there in a slide rather than squatted down on the suspension and waiting to arrive at that same point while wasting time waiting to get there. I know it sounds weird but that is what I was doing and that apparently looked pretty spectacular from the outside.

As far as your question about MS turning earlier than MH, and who would exit faster, IMO, there really is only one point (spot on the track) that is optimal to get on the power and then exit. How you get to that point, even throttle, turn in early and slide, turn in late and slide, whatever, the exit speed should be the same and if not, you should be using whichever one allows you to be at that spot and fully capable of accelerating at the optimal speed. The maximum possible. Assuming they braked at the exact same instant, and accelerated at the exact same instant on the exact same spot, whether you got to that point on a narrower or wider arc might show a difference in the time it took between the braking and acceleration points. But I don't know which would be faster. Probably the one that covered the least ground and therefore MS's. If however as you suggest, MH's wider arc allowed him to exit faster, that is the one that MS should be using.

Frankly I was watching these guys in qualifying a few hours ago and I didn't see any of what we are talking about taking place. But I suppose it is noticeable on the telemetry if it is indeed happening at all.

[merlyn6]

Originally posted by Buford
All I do know is I could out brake everybody and that had serious gains in competition.

I believe this was due to you adjusting the brake bias more towards the rear than your competition. This requires a much higher level of car control skills, which it appears you possess, but it is effective. except on downhill braking I’ve found that the older I get, the further towards the front my brake bias is set.

[karlth]

Originally posted by merlyn6
I believe this was due to you adjusting the brake bias more towards the rear than your competition. This requires a much higher level of car control skills, which it appears you possess, but it is effective. except on downhill braking I’ve found that the older I get, the further towards the front my brake bias is set.

You mean to the front, don't you? The higher the front brake priority is the more effective the
brakes and more unstable the car. Am I confusing something here?

[rdrcr]

Originally posted by merlyn6
"... The use of trail braking is dependent on the corner, or more correctly what precedes and follows the corner. In the case of a long straight following I don’t trail brake, as the corner exit speed is not as high as it is in the case of straight line braking. This increased speed is too much of an advantage on the next straight, however if the corner follows a long straight, then trail braking might be advantageous. Trail braking works best when you have a series of corners, not connected by a long straight. It all depends on what part of the course you want to maximize. It’s a tool in a driver’s arsenal to be used when necessary. Left foot braking is a totally different thing, something which I have no experience with.

Interesting thoughts about when to use trail braking Merlyn... I've always thought that the most important corner or curve on a race track (generally speaking) is the one preceding the longest straight. Thus, I'd think that, that would be the most important time to use trail braking - on that corner or curve.

I don't think I'm alone in this theory as I've heard this from many racers and instructors. The most recent and pertinent to this discussion was from Danny McKeever, of Fast Lane Racing Schools. He put me through my Super School test at Buttonwillow. I've known Danny for a while, he was our instructor when we first started to fool around in '88 at Willow. At that time, during some instruction, he indicated that the exit of turn 9 was more important than the exit of 5. He said he used trail braking to drift the car (a Toyota Celica) out to the edge of the decreasing radius curve. Though he didn't teach us the technique at the time for obvious reasons.... Anyway, (the turns 8 and 9 are linked and 9 is a decreasing radius) a very tough turn to do fast in a car, and trail braking only increases the chances for disaster. The main straight following 9 is longer than the back straight.

I thought that I'd bring this particular situation up as you've probably driven it or know of it at least. I think that this would be contrary to your definition of when to use trail braking. Perhaps I just don't get your meaning of; "...This increased speed is too much of an advantage on the next straight..." I then read where you state that "...It all depends on what part of the course you want to maximize..." So I think that you quantify your statement a bit here.

Re: Left foot braking; left foot braking was naturally easy for me, as I had 10+ years of experience in Karting where left foot braking is the norm. When I changed my engine / trans set up in the CSR from a Mazda to a MC engine, the lap times fell. Not because there was more power, but the way the transmission was used in relationship to the braking. I could left foot brake again and joy was felt once more.

Even with a more traditional set-up as in the Chevron, I think that left foot braking will be experimented with straight away. Trail braking on the other hand will come at a gradual pace as those kinds of mistakes that happen from it are not an option. I'll only attempt the technique when I'm really comfortable with everything and where there is plenty of run off room...


Ricardo, you got those signs too huh?;)

[Buford]

You mean to the front, don't you? The higher the front brake priority is the more effective the
brakes and more unstable the car. Am I confusing something here?

---------------------------------
No the more the rear brake bias, the more likely at maximum braking the rears will lock first and throw the car into a spin so when I did have an adjustor I did probably have it more to the rear than front. But mostly I induced the slide by snapping the wheel and turning when I was still going too fast for the car to turn. This was where I was different because the traditional method has you only turning when you are already braked and ready to turn. I would counteract massive understeer in some cars by a more violent snap. In cars that tended toward neutral or oversteered, it happened on its own by turning early while going too fast to turn.

But you young guys have to realize these were ancient times in the 1970s. We did not have bias adjusters until the mid-1970s. Probably half the cars I ever raced did not even have that adjustment. Or many other adjustments either (the non formula cars that is). Basically we drove what we had and drove around bad handling rather than adjusted the bad handling away. You have to realize, much of what every first year racers know today was not known by even the professional teams in the early 1970s. The science of vehicle dynamics we know today was to a great part discovered by the Penske and Donahue team and Jim Hall, both working with GM engineers and that was taking place in the late 1960s, early 1970s. That stuff did not even trickle down to the other professional teams until the mid 1970s and to the amateurs by the late 1970s and early 1980s. We didn't even have slicks until about 1972 or 1973.

[karlth]

Correct, my mistake. That should explain some simulator spins.

Found this which confirms your statement:

IMHO, too much rear bias is *always* a bad idea on the street. It
won't stop the car any faster than slight front bias, but will
significantly reduce the car's stability near max decel.

On the track, extra rear bias may help the car to turn in under
braking (by reducing the car's stability), but you'll have to mix
turning and braking very carefully to avoid a spin.

[merlyn6]

quote:
You mean to the front, don't you? The higher the front brake priority is the more effective the
brakes and more unstable the car. Am I confusing something here?

Actually the higher the front priority the more stable the car.

No, I mean biasing the brakes just a little towards the rear. What this does is allow the front wheels to maintain steering capability even when the car is under a severe braking condition, in other words almost lock up.
It requires a very high level of driver skill to control a car under severe braking with rear bias, but it can be done. Front bias is much safer which is why all road cars have front bias. It must be noted that when I say rear bias I mean very little. One half turn so on the bias bar is all, or in some cases simply not as much front bias as others. Bias is changed in very small degrees.

[merlyn6]

Interesting thoughts about when to use trail braking Merlyn... I've always thought that the most important corner or curve on a race track (generally speaking) is the one preceding the longest straight. Thus, I'd think that, that would be the most important time to use trail braking - on that corner or curve.

Think of it this way. At some point in a corner you will be at your slowest speed. You have the option of moving this point up or back. If you opt to be at your slowest speed sooner in the corner, (straight line braking) you are able to start accelerating sooner, maximizing the straight following the corner. In other words, your speed at track out will be higher. Please note that I have not driven a car with an adjustable bias bar. I race a 1969 Brabham BT29 FB car, so I may be a little behind the times