Driver styles/preferences

[Ciro Pabón]

Oh, please don't take offense in anything I've said, by no means I was trying to refute anything you said there!

Timbo, I cannot take offense from you. I consider you a friend and I think I speak for everybody when I say that we all appreciate you being here. It wasn't my intention to disturb you (at all!), I wasn't being sarcastic. I sincerely think you're a master in this forum (for starters, your avatar says so!). Besides, you can refute me anytime you want, you know I don't react when somebody criticizes me or points out when I'm mistaken, that's the purpose of this forum for most of us: to learn and spend a good time together.

Over all, if I were upset when somebody refutes me, I would be an a&%hole. I repeat what I've said many times: in engineering there is no authority and I know Tomba agrees with that. Every argument has to be defended by its own merits.

I was just going out of my house for lunch, so I ceded you the floor, for you to speak about the issue. You know me, I'm only mildly angry when somebody speaks badly of ANY driver...

[Lurk]

Button, who supposedly prefers an understeery car, said Pirellis suit his style.
Yesterday Sutil said Pirellis tend to oversteer.
So, which is it? It's not like it could be both at the same time (beside serious issues with the setup of the car).

Button was firstly talking about the feeling of the tyres. Maybe the Pirelli tends to oversteer but grip falls in a smoother way than the Bridgestone?

So, you better brake early and longer, enter slower and wider into the corner, turn with all your might and quickly straighten the car for a long exit

I'm not an expert but: do you not shoot the brakes very late and start cornering at slow speed when you start releasing the brakes (when the rear is still light so turn easily)?

You could also talked on car behaviour changes during cornering. For example, I know that 996 GT3 RS tends to understeer a little on the enter and has a slight oversteer on throttle. You cannot totally avoid it by setting up your car: it is inherent to the Porsche (due to its weight repartition I guess).

So I turn a little earlier but accelerate earlier too. By exaggerating, it's like cornering for an early apex and throttle like on a late apex in order to meet a mid-apex.


Very nice post by the way.

ps: To superelevation information, why not try to get track models on video games?
Some models are laser scanned, so they should be pretty accurate.

[Ciro Pabón]

So, you better brake early and longer, enter slower and wider into the corner, turn with all your might and quickly straighten the car for a long exit

I'm not an expert but: do you not shoot the brakes very late and start cornering at slow speed when you start releasing the brakes (when the rear is still light so turn easily)?

Well, very good point. This has lead to very long discussions at Tocancipá´s JPM kart track (where I used to race). I always argue that it is impossible to take a tighter turn if you brake late. I cannot do it like that. If I brake late, I go faster into the curve, so I miss the late apex completely. The only way I can get a late apex is when I brake more and I take the curve slower. Perhaps other members can give a better explanation or a better technique. I have the record right now at the kart track I started to practice in Cali a couple of months ago (and I'm 51 years old!). I got it right after we discussed the very same point with the guys in charge of the track, I got it on the very second lap of explaining how I do it and then, I wasn't able to repeat the feat... and the record has already been broken again.

I'm always saying that if your late apex technique includes a later brake, then you're braking too soon when you use mid apex.

I'm a member of Race Sim Central, but I haven't been there in ages. When I made the restitutions I mentioned, I received laser profiles for Monaco. Now, I do them, I bought a LIDAR last year, but I've used only for road design. I haven't had the chance to see laser profiles of circuits for Sim Racing, but I imagine they are common, because LIDARs are dirt cheap these days.

[raymondu999]

Button, who supposedly prefers an understeery car, said Pirellis suit his style.
Yesterday Sutil said Pirellis tend to oversteer.
So, which is it? It's not like it could be both at the same time (beside serious issues with the setup of the car).

I think there's a common misconception that Button likes understeer. But if you think about it, a smooth driving style like the way he moves the steering wheel will suffer with understeer, as he can't do his normal "sweep in, sweep out" style. He even said it himself. He just wants a front that is stable, and a rear that is stable. Basically, an all-around stable car, which is easily predictable.

[Jersey Tom]

Statements such as "driver X likes a car that over/under-steers" annoy me because they are generally taken out of context, propogated further by armchair engineers, and then taken as gospel by the forum community at large.

This.

[lolzi]

Statements such as "driver X likes a car that over/under-steers" annoy me because they are generally taken out of context, propogated further by armchair engineers, and then taken as gospel by the forum community at large.

This.

That might be so, but everyone knows Schumacher prefers oversteer.

[raymondu999]

Sorry I don't quite understand. What context should they be taken in? (I'm sorry if I sound sarcastic/condescending, I'm not. I'm genuinely asking a question which I don't understand

I don't think anyone prefers over/understeer, actually. Those two mean that you're not using the maximum grip your car can provide. What most people usually mean, I guess, is "pointy" and "stable" cars.

Looking at some onboard from Hamilton, Vettel and Webber in 2010, I was just noticing the telemetry that they show on the TV screen. Most of them brake for a corner during the turn-in towards the apex, then power out from the apex. I was thinking though, wouldn't that actually cause them to have some over/understeer depending on their brake bias arrangements? Also, wouldn't it mean that their grip is used for cornering AND braking, rather than just for cornering? A late apex, by contrast, should be brake-turn-power, right? Kind of like a more "V" shape.

I always thought conventional wisdom was slow in fast out was the generally faster approach. Or am I missing something here? If I am, an explanation would be nice

[speedsense]

...if a car is perfect and has perfect neutral handling, as an engineer I would expect the driver to drive it so hard that some negative handling aspect occurs, otherwise he simply isn't driving it hard enough.

The "concept" that driver's prefer a car to handle a certain way to be fast, is not fitting to someone, who in their career has achieved the crown of F1 six times.
Was this because the car was perfectly suited to his driving?

OR does Schumi have more than one technique to suit a situation? IMHO, the latter is true of just about all of the F1 drivers, especially strong in the great ones.

IMHO, drivers who reach F1 and do well in it, have multiple techniques that they can enact, at any given moment, for any aspect of a car's handling and a track's aspect . Not one driver in F1, who has A)won races or B) won championships, is stuck within one technique that best suits them, but rather they suit their technique and adapt to the given circumstances and do so in the blink of an eye. This is in the makeup of any great driver, especially F1.

A one style driver, is not a F1 driver, at least not for very long. Money helps, but only for so long....

Raymondu999 wrote:
I always thought conventional wisdom was slow in fast out was the generally faster approach. Or am I missing something here? If I am, an explanation would be nice

No, you are correct...though it's more like...drive the slow corners slow (at some point) and the fast corners (fast).... the most "important" key, is time percentage, spent at full throttle. (hence the slow in, fast out on slow corners)
However to add to this statement, maximizing the grip of the tire from initial turn in to exit throttle on AND arriving at full throttle before anybody else...

[Jersey Tom]

Saying driver X likes U/S and driver Y likes O/S bugs the hell out of me. There are many reasons why.

For one, the definition of U/S vs O/S or "tight" vs "loose" or whatever measure of balance, isn't as straightforward as you think. I have a whole blog entry on this. It varies among professional drivers and among professional engineers. Beyond that, the differences you're talking about are going to be fairly subtle. No driver is going to want their car to plow like a dump truck or drift the whole track like a Formula D event. Either of them is going to be embarrassingly slow - period.

To ask a driver if they want a U/S car or O/S you might as well be asking them if they would rather date "Jen" or "Melissa". By itself, it's meaningless. Balance is going to be different at high speed versus low speed. It's going to be different in pure cornering versus on the brakes versus on the throttle. By that alone, you have 6 different "events" you're interested in. And yes, Raymond... by your observations on telemetry the car balance will change with brake and throttle application as you go through a corner, but trail-braking is absolutely necessary to be fast. On the same setup, on low speed corners you can have power-on oversteer, and in high speed corners be stuck with power-on understeer. As an aside, this is also why I don't like asking a driver "How's the exit balance?" because it can be completely different from one corner to another.

Beyond that, you have to know what specific behavior the driver wants in each of those different "events" or combined driver inputs. I can think of a handful (let's say 3-5) parameters that are important in each case... so it's pretty easy to have at least 18-30 different variables to characterize the behavior of the car. In reality it's many more the way I think of it, but this is just a simplification. Each of those variables can have a range of values.

For me, as an engineer, the notion of taking those 20-30 values and condensing it down into a purely binary 1 or 0, "understeer" or "oversteer" assessment - is silly.

Doesn't just apply to professional drivers either. Anyone who has any seat time can probably appreciate this. My favorite is among FSAE drivers (I know I've gone on about this before). I recall a dialogue going like this...

(Car comes in)
Me: "Can you describe the handling and balance of the car?"
Driver: "It oversteers all over the place!"
Student Engineer: "Ok. Guess we need more front stiffness."
Me: "Hold up... so how did the car feel around the apex of some of those sweeper corners?"
Driver: "Well... it was pretty tight, didn't turn great." (Not oversteering all over the place then is it! This, is the danger of taking things out of context)
Me: "Adding front roll stiffness probably isn't your best bet then."

[speedsense]

Saying driver X likes U/S and driver Y likes O/S bugs the hell out of me. There are many reasons why.

For one, the definition of U/S vs O/S or "tight" vs "loose" or whatever measure of balance, isn't as straightforward as you think. I have a whole blog entry on this. It varies among professional drivers and among professional engineers. Beyond that, the differences you're talking about are going to be fairly subtle. No driver is going to want their car to plow like a dump truck or drift the whole track like a Formula D event. Either of them is going to be embarrassingly slow - period.

To ask a driver if they want a U/S car or O/S you might as well be asking them if they would rather date "Jen" or "Melissa". By itself, it's meaningless. Balance is going to be different at high speed versus low speed. It's going to be different in pure cornering versus on the brakes versus on the throttle. By that alone, you have 6 different "events" you're interested in. And yes, Raymond... by your observations on telemetry the car balance will change with brake and throttle application as you go through a corner, but trail-braking is absolutely necessary to be fast. On the same setup, on low speed corners you can have power-on oversteer, and in high speed corners be stuck with power-on understeer. As an aside, this is also why I don't like asking a driver "How's the exit balance?" because it can be completely different from one corner to another.

Beyond that, you have to know what specific behavior the driver wants in each of those different "events" or combined driver inputs. I can think of a handful (let's say 3-5) parameters that are important in each case... so it's pretty easy to have at least 18-30 different variables to characterize the behavior of the car. In reality it's many more the way I think of it, but this is just a simplification. Each of those variables can have a range of values.

For me, as an engineer, the notion of taking those 20-30 values and condensing it down into a purely binary 1 or 0, "understeer" or "oversteer" assessment - is silly.

Doesn't just apply to professional drivers either. Anyone who has any seat time can probably appreciate this. My favorite is among FSAE drivers (I know I've gone on about this before). I recall a dialogue going like this...

(Car comes in)
Me: "Can you describe the handling and balance of the car?"
Driver: "It oversteers all over the place!"
Student Engineer: "Ok. Guess we need more front stiffness."
Me: "Hold up... so how did the car feel around the apex of some of those sweeper corners?"
Driver: "Well... it was pretty tight, didn't turn great." (Not oversteering all over the place then is it! This, is the danger of taking things out of context)
Me: "Adding front roll stiffness probably isn't your best bet then."

Sounds like a case for data acquisition....

Which brings up the eternal question, When is it Understeer? As it varies from driver to driver. Some can't stand even the smallest understeer. Others don't complain at all and call it neutral in the same car.

By far, the hardest handling condition to contend with/trace/track/ measure is understeer. Of the two evils, I contend that a small amount of understeer is a better condition than oversteer, IMHO...

[Tim.Wright]

Sorry I don't quite understand. What context should they be taken in? (I'm sorry if I sound sarcastic/condescending, I'm not. I'm genuinely asking a question which I don't understand

By out of context I mean, driver X gives an interview saying "the car was oversteering in the corners Y and I didn't like it" - everyone then decide driver X prefers an understeering car, and the BS propogates from there.

Tim

[Tim.Wright]

Which brings up the eternal question, When is it Understeer? As it varies from driver to driver. Some can't stand even the smallest understeer. Others don't complain at all and call it neutral in the same car.

I have heard quotes from engineers say driver X likes a car which over/understeers at the limit. Still I wouldn't necesarily take that information as general, but at least here it has a context.

In this case, to answer your question (when is it understeer) it is when the car is limited by the front axle in terms of maximum lateral acceleration.

Tim

[speedsense]

Which brings up the eternal question, When is it Understeer? As it varies from driver to driver. Some can't stand even the smallest understeer. Others don't complain at all and call it neutral in the same car.

I have heard quotes from engineers say driver X likes a car which over/understeers at the limit. Still I wouldn't necesarily take that information as general, but at least here it has a context.

In this case, to answer your question (when is it understeer) it is when the car is limited by the front axle in terms of maximum lateral acceleration.

Tim

I know that Tim, know it very well...
The point is understeer is a different number for every driver you will encounter...

According to which driver? Most drivers WANT to push the car harder the NEXT lap around and rotate past the understeer to make the car neutral. In high speed corners with Oversteer, the driver would have to be an idiot to push harder...or have lots of money to pay for the damages.... At least from the driver's point of view, if he's sharp, oversteer is a limiting factor, once you have it, you aren't going any faster (at least in that corner). Understeer on the other hand, press on.. "the cars neutral now"...press on...whoops oversteer...Can't press on ..... ahh a path to faster speeds...and the point of conversation.

BTW, I'm not talking but a small amount of oversteer/understeer...

Understeer is subjective from driver to driver to driver. Especially a driver directly out of go karts, understeer is an evil thing, and very, very, very slow in a go kart. Take that to a car, and comparisons by the driver are made... the slightest understeer and the driver objects... (BTW, the same goes for roll, as when a kart rolls it lets go.....) Neither are reality in a race car....

[Tim.Wright]

Its irrelevant which driver, I just gave a (one possible) definition of understeer. That was your question wasn't it?

If you want a more complete definition on os/us read Milliken. OS/US sub-limit is a function of slip angles of the axle and the lateral acceleration if I remember correctly.

Tim

[speedsense]

Its irrelevant which driver, I just gave a (one possible) definition of understeer. That was your question wasn't it?

If you want a more complete definition on os/us read Milliken. OS/US sub-limit is a function of slip angles of the axle and the lateral acceleration if I remember correctly.

Tim

Tim,
I've owned Milliken since the first year it was produced..

I don't need a definition, you do... after 20 years of racing, I know what I'm talking about.
In data acquisition, it is still undefined what understeer is, (even with the math equation of calculating vehicle path) because of the driver... what is understeer to one driver isn't understeer to another one. No amount of data, engineering, math or whatever is going to correct it. It is what it is. The driver dictates whether the car has understeer or doesn't, based solely in his ability of car rotation, and how he drives...he can "mask" it from view, to you, and the data system.
My point is that understeer of the two handling disorders, is the more stable of the two, as the driver can actually increase speed because of it, and do so with confidence, mainly in high speed corners, the most dangerous aspect of a handling disorder.

Understeer is a moving goal post....highly experienced drivers can move that goal post at will and do so with a lot of confidence...

If our team had a corner that we knew was flat out, but our team had not it done so, so far. Would you put oversteer in the car or understeer? The answer is obvious, understeer for confidence...