the real truth about under steer

8/2/2019 The Real Truth About Under Steer

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The Real Truth About Understeer________________________________________

There was a post made recently that supposedly exposed the "truth" about Subaruundersteer. In summary, someone on this forum watched a video of a driver sayingthat driving too smoothly causes understeer, and that the proper way to corner in aSubaru is to violently whip the steering wheel 70 degrees or so on turn in to

eliminate understeer.

Now, hopefully, I don't need to tell you that this is a load of crap. However, the factthat someone watched this video and had some sort of epiphany and wanted toshare it with others on this forum was REALLY SCARY. I ended up accidentallywriting a fairly long post about how to properly enter a corner in a Subaru, and thenwent off on a somewhat of a tangent about understeer in general. Because of this, I

felt it would be a good idea to take what I already wrote and expand a little bit. It

should help 98% of the drivers out there, as understeer is probably the mostcommonly misunderstood driving concept there is.

If you go to the track, you should read this. Even if you think you know everythingthere is to know about understeer, you'll probably learn something.

The Real Truth About Understeer

What exactly is understeer? In purely technical terms, it's a lack of front tire grip.But what does that actually mean? What causes it? How can you get rid of it mid-

corner? How can you avoid it altogether? And most importantly, why is it actuallyMORE dangerous than oversteer?

First, let's understand exactly what understeer means. When you enter a corner andthe car begins to "push" toward the outside of the turn, you're experiencingundersteer. You've dialed in the correct amount of steering input (turned the wheelthe correct amount) but the car is turning less than it should.

REASONS FOR UNDERSTEER

So, why does this happen? This happens because your rear tires have more grip thanyour front tires. When you begin to turn, instead of the front tires gripping on theroad, they slide. This can happen for one of three basic reasons:

1) You've entered a corner too fast (surprisingly, this isn't usually the problem!)2) You're trying to turn too much (you've actually asked the tires to do more thanyou need them to do)3) Your brake and/or throttle inputs haven't loaded the front suspension properly

(this is your problem, 95% of the time)

Let's discuss #3 first, as this is the most common cause of understeer. Tounderstand load transfer, also commonly (and incorrectly) referred to as weight

transfer, perform this simple exercise:

Place your hand face-down on the table/desk in front of you. Slide it forward on the

table. Your hand slides easily because you have very little load forcing it on the table.Now stand up, and lean on your hand. While leaning on your hand, try to slide itforward. It doesn't slide. This is because you have a lot of load on your hand. The


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same exact thing is constantly happening with your tires. When you have load onyour tires, they grip. When you don't, they slide.

Simply put, when you accelerate, load is transfered rearward. When you decelerate,load is transfered forward. Deceleration doesn't necessarily mean braking, ascoasting or even easing off the throttle will cause the vehicle to slow down

(decelerate). This is even more dramatic when driving up hill, as the slightestdecrease in throttle input causes the car to decelerate significantly.

BRAKE RELEASE

So, we know that understeer is caused by a lack of front grip, and we know that wecan increase front grip by transferring load to the front of the car. So as long as we

decelerate before every corner, we'll never understeer ever again! Right? Well, it's

not quite that easy.

The way in which we brake and accelerate, or more importantly, the way in which we

release the brakes and roll on the throttle, determines how the load is transfered,how much load is transfered, and most importantly, how much load actually STAYSin the front of the car.

If we brake very hard, a lot of load is sent to the front. However, if we abruptly liftoff the brakes and get back on to the throttle, all of that load goes right back to therear. In fact, when you're accelerating hard, the front tires have so little load that

they're barely making contact with the ground. Just think about how well your carwould steer if you were doing a wheelie through the turn.

So, how can we accelerate through a corner and still maintain a healthy amount offront load and grip? The answer is proper brake release, followed by sensitivethrottle input. Ideally, a passenger should not be able to tell when you've gotten offthe brakes and on to the gas.

To do this, you need to revise your braking strategy. Braking "late" or "diving" in tocorners and getting on the power early may seem like the fastest way around thetrack, but this usually slows people down. There is a way to brake late and get on tothe throttle sooner, but it can't happen until you've mastered proper brake release.

To start out, brake 10-20% earlier than you normally would. Try to get all of your

braking done well before the corner. At this point, you should feel like you broke tooearly. You have a quarter to half a second of time, which feels like an eternity, inwhich you don't need to be slowing down anymore, but you don't need to be turningyet. During this "dead space" you focus on one thing, and one thing only: brake

release. This is your time to gradually release the brakes and begin to turn in. As youget comfortable with this, you can begin braking where you normally did before,combining this smooth brake release with your turn-in, often referred to as "trailbraking." You then need to follow this up with an equally smooth and gradual

application of throttle. Smashing on the gas at this point will ruin all of the workyou've done up this point with your brake release.

If done correctly, one of two things will happen depending on a variety of factors:

1) The car will be perfectly neutral through the turn and will turn exactly the sameamount as you turn the steering wheel.


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2) The car will oversteer slightly, turning more than you turn the steering wheel.

No explanation is needed for #1. You're good to go. Congratulations, for the firsttime ever, your Subaru isn't fighting you through a turn.

OVERSTEER AND "ZERO-STEER"

Next, we have situation #2. This is a GOOD situation to be in, do not be afraid!Clearly, hell has frozen over, as your Subaru is oversteering. How could this havehappened? The answer is you've successfully trail braked to the point that youactually have so much front grip that your car is able to turn more than you asked ofit. Depending on how quickly you recognize this behavior, you may be able toexperience something we call "zero-steer."

As soon as the oversteer initiates, you can roll on the power. If you're quick enough,you'll barely need to correct your steering input (counter-steer) as your throttle inputwill send load to the rear, reducing front grip. This reduction of front grip stops the

oversteer, and you may end up with "zero-steer" where the steering wheel is in thedead center position and the car is turning around the corner almost by itself. At thispoint, you're simply steering with the gas pedal. More gas steers towards the outside

of the turn, less gas steers towards the inside of the turn, and maintaining throttlekeeps you on your current path. This is not only the fastest way around the corner,it's also the easiest on your tires. Unfortunately, even for the best of drivers, it's notsomething you'll experience every corner, but it's sure nice when you do.

Now, assuming you're not quite quick enough and you catch the oversteer a little

late, you'll need to make a slight counter-steer correction. This is extremely fast, andextremely minor. We're not drifting, we're not going around the corner with thesteering wheel turned in the opposite direction. Simply reduce your steering input (oreven temporarily steer in the opposite direction for a split second) and slowly get onto power. Things will quickly sort themselves out and you'll be going around the turn

with very neutral handling. Continue rolling on the power, but don't accelerate toomuch! You'll just end up with understeer again.

As you unwind the wheel and start exiting the corner, you can accelerate more andmore. When the wheel is almost straight, you can fully accelerate. It is for thisreason that we want to get the car rotated early. The more turning we do at thebeginning of the corner, the less we have to do at the end, which means we spend

more time on the gas, and less time steering.

I THINK THAT MIGHT BE A BIT BEYOND MY SKILL LEVEL

If this oversteer / zero-steer situation has you scared, or you don't feel that you willbe able to recognize the oversteer soon enough, there is absolutely no reason thatyou ever need to be in this situation. The only way for this to happen is by trailbraking too much. This means your brake release continued too far in to the

beginning of the corner.

To assure that this doesn't happen to you, simply finish your brake release in a

straight line, and start your sensitive application of throttle at turn-in. As you getmore and more comfortable, you can try trail braking a little at a time. Do yourbrake release 1% in to the corner, then 2%, then 5%, etc. Eventually, as you getmore confident, you'll find yourself trail braking the first 10% of most corners. Please,


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PLEASE, keep in mind that "trail braking" is NOT actual braking. This is simplycombining your brake release with your turn-in. If you're actually doing any kind of

real STOPPING during your turn-in, you are asking for trouble!

THAT'S GREAT AND ALL, BUT I SCREWED UP AND THE CAR IS UNDERSTEERING ASUSUAL. NOW WHAT?

When you can't prevent understeer, you can eliminate it mid-corner. Doing soproperly is essential, as improperly dealing with understeer is the most dangerousthing you can do, and is responsible for most accidents at the track. "But I thoughtundersteer was safe!?" Well, it's not.

THE MOST COMMON, YET COMPLETELY UNKOWN MISTAKE WITH UNDERSTEER

Before we can talk about eliminating understeer mid-corner, we first need tounderstand the common mistake that most people make to get them in to really badsituations in the first place. This problem is turning the wheel MORE once the car has

started to understeer.

When you think about it, it makes sense. If you want the car to turn more, you turn

the wheel more, right? Wrong. What?! If you've asked your tires to turn a certainamount, and they can't, how is asking them to turn even more going to helpanything?

An example of this would be in a gym. A man is bench-pressing 200 pounds. Healmost has the barbell all the way up, but he's struggling. Then his friend comes over

and adds another 20 pounds of weight to his barbell. In this situation, there is noway that the man will be able to lift the 220 pounds, instead, he'll probably drop theweight on top of himself. This is no different with your car, all that will happen is itwill understeer more and start to drive completely off the road.

GOT IT. SO NOW WHAT?

So, your car is starting to understeer in a corner. You catch yourself right before youinstinctively add more steering. Now instead of having a serious understeer problem,you have options:

1) Reduce your steering input (turn less)

2) Reduce your throttle input (decelerate)

The first option is important to consider. Many times, maintaining your current speedwith just a little less steering input is all that is needed to reduce your understeer. If

doing so will still allow you to make the corner, you're golden. If it's clear that you'regoing to drive off the road at your current radius, you move to option #2.

Option #2 has to be dealt with very carefully. As we know, decelerating will send

load to the front, increasing front grip. This is a good thing, but too much, tooquickly, will cause oversteer. For this reason, you need to be very gradual andsensitive. Lift slowly off the gas. With 10% less throttle will you make the corner?

20%? 30%? Are things really bad? Maybe you need to let off completely, or evenbrake. That's OK, as long as you do it gradually and smoothly. If you simply lift offthe gas and step on the brake you will cause oversteer that is so quick and so violent,you will spin, and exit the track sideways or backwards, guaranteed.


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SO UNDERSTEER IS DANGEROUS, AND OVERSTEER ISN'T? THAT SEEMS PRETTY

BACKWARDS

Oversteer can be dangerous, but unlike understeer, there are two major kinds ofoversteer. There's controllable oversteer, and uncontrollable oversteer. The

oversteer you'll experience from trail braking for example, is easily controllablebecause it's gradual and you're expecting it.

Another kind of equally controllable oversteer is power-on oversteer. This is possiblythe easiest kind of oversteer to correct. You got on the gas too hard, too soon, andthe rear tires are spinning? Let off. Your problem is gone. The only way to spin out orcrash as the result of power-on oversteer is to try to be a drifting, power-sliding,

hero that doesn't want to lose a few tenths of a second letting off the gas and

regaining traction. As soon as you feel that you've induced that kind of oversteer, liftyour right foot and it goes away. That's all there is to it.

SNAP-OVERSTEER

Now, uncontrollable oversteer almost always comes after bad understeer and is

commonly referred to as snap-oversteer. This happens when you improperly dealwith understeer, and this is usually what people think about when they hear theword "oversteer." It's scary, and it's usually the only kind of oversteer that mostdrivers experience.

We'll take a typical understeer example. You've failed to properly load your front

suspension and/or you're just entering a corner way too fast. The car begins toundersteer. Because you haven't read this post, you turn the wheel more to try tomake the car turn more. Now you realize that the car is almost certainly going to gooff the track and you're running out of road. The outside of the corner is gettingcloser and closer. You panic and lift off the gas completely and suddenly, maybe

even brake. In a split second you go from having excess steering input with no frontgrip, to excess steering input with an abundance of front grip. What happens? Thecar turns like you want it to, and then it keeps turning REALLY fast. You try to reactby counter-steering, but by this point, it's already too late. In fact, it was already toolate when you lifted 2 seconds ago. You're sideways, then you're backwards, andnow you're spinning.

What should you do? Well, if you haven't already, you should be hard on the brakes.In fact, as soon as you went more than about 45 degrees sideways you should havebeen hard on the brakes. But what do most people do? They don't even get on thebrakes until they're going backwards, and even then, sometimes they still don't

brake. The net result is going off the track sideways or backwards, which can resultin rolling the car or hitting a wall. All of which could have been avoided at that verymoment you turned the steering wheel more.

That is truth about understeer.

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Here is some more good information coming from questions in later pages of thisthread:Quote:


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Originally Posted by severereading this i think i'm always way too jerky with the brakes

I wanted to make a slight clarification here as some people may misunderstand the"smooth" braking technique. When you get ON the brakes, it needs to be forceful,hard, and well, it can be down right jerky. Depending on your brake setup,suspension, aero, etc, the initial half second of braking is when most of the stopping

is done. It's extremely intense G's and probably can't be done properly without agood seat and harness. It's also something that most people don't do correctly, as itfeels natural to progressively get on to the brakes (rather than basically slam them),but that actually increases your stopping distances, heats your brakes more, andreduces pad and rotor life.

To complicate things a little bit, there is the whole theory of "outrunning the load

transfer." This is rarely an issue in any track-worthy cars, but is more important in

something like a dirt truck, where you have FEET of suspension travel, not inches,and it can actually take quite a bit of time (second+) for load to actually transfer tothe front. In this case, slamming the brakes would instantly lock up the front tires

since there is no load on them to do any braking. In an STI, it really shouldn't be anissue, especially not with coilovers.

After this initial braking period, you're easing off the brakes a bit (because at theslower speeds you'd lock up the brakes and/or trigger ABS), and doing yourdownshifting.

Once your downshifting and braking is done, you get in to the smoothness that isbeing discussed in my post, which is your brake release. Getting ON is rough, getting

OFF is extremely smooth.Quote:Originally Posted by Chris05STiIt was like your were in my head! Very good info, makes sense. We should have aForza 3 meeting online for this!

Indeed. It's actually fun to mess with in Forza. One of the biggest things you canimprove in that game is not mashing the joystick all the way to one side. The sameconcept applies in that game, if you push the joystick all the way to one side (fullsteering lock) you're asking your tires to turn more than they need to and causingundersteer.Quote:

Originally Posted by severewell yeah my initial braking is really hard, i found this to help my times sometimes iget a single chirp from the abs kickin in also. i havent been to the track yet but myseat time is mainly in autox and im pretty much learning.

i generally slam them hard right before the turn, but reading your post i realize whati never do is release them smoothly. i just drop the brake pedal and then get my footon the gas. i dont slam the gas i have a pretty good feel for the throttle and how the

car reacts to minute adjustments mid turn.

based on what you wrote though it seems like i should take a split second longer in

my brake release. i dont know how practical it will be since our autox setups aregenerally really tight and technical but its worthwhile to try and see if it'll help mytimes.


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right now i can rotate the car a tiny bit with just throttle if i have the dif set to open,and it has some very slight understeer if i'm accelerating through the turn 1 notch up.

btw this has been on my mind, im generally screeching my tires around the entirecourse. i keep wondering if this is slowing me down or not. its right at the thresholdusually i.e. if i remove a very small amount of steering input the screech goes away.

i noticed most other guys aren't so aggresive though (though most of them alsohave rwd)Two things here. First, this obviously matters a lot more at the track than at an autocross, but the concept can still be applied. No matter what corner you're talking, alittle trail braking will benefit your Subaru. It's just going to be an even quicker brakerelease in auto x because you brake considerably less and you're not going fastenough to be able to really get on the pedal hard without the ABS coming on.

As for tire screech, try not to rely on that. It's more of a crutch than anything. Reallygood r-compounds and any slick are completely silent. You don't hear any noise atall until you're backwards. The same goes with lockup / ABS, they don't chirp, you're

just see silent tire smoke in your rear view (or in front of you in an open wheel car ).

The key is to feel that understeer coming on BEFORE the tires have to tell you about

it. First, because if you correct it really early or avoid it altogether, you'll go muchfaster. The second reason is obviously as you get better tires you'll stop getting thataudible warning. Now, with street tires and street suspension, you still have plenty oftime to correct if you wait too long because everything is somewhat in slow motion.

If you go to a stiffer, lighter car with stickier tires, everything happens much faster.Quote:

Originally Posted by santacruz02Ben, I'd assume the size or width of the front tires makes a difference as well. Likepossibly understeer was cause from not having enough tire to pavement?This actually makes no difference, unless you're suggesting running a DIFFERENTsize tire in the front versus the rear. Whether you have 225's on all four corners or

315's you're still going to have identical understeer characteristics basically. The onlydifference is you'll get it at a slightly higher speed, but when the grip is still going togive up at the same point in the same fashion.

When you see cars with wider tires in the back than the front, they do this toartificially reduce front grip to compensate for oversteer problems. This is particularlynoticeable in a Porsche.

You can actually mess with this in the opposite direction with a Subaru and it's kindof fun. Like running 245's in the front and 225's in the back, assuming you can find atire with the same overall diameter as to not slowly destroy your center diff. Another

way to toy with this is to run new tires on the front and used tires on the rear. I usedto do this quite a bit, but just know that if you trail brake now, you'll DEFINITELY getoversteer.

Also, please keep in mind when I'm talking about new and used tires I'm talkingabout race tires, so the difference at most is 2/32's tire depth. If you put new streettires and almost bald street tires you'd probably have a 5/32's difference which isn't

so great for your center diff.


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Last but not least, and the easiest thing to adjust, is your tire pressures. Runningmore pressure in the rear than the front will also help make the car more neutral, or

more oversteer prone after aggressive trail braking.

Obviously you can adjust suspension settings, swaybar settings, etc, but I like to goto them last for the fine tuning. I'll first start out with what makes the biggest

difference (tires), then move on to aero (adjust rear downforce), and then move onto the suspension when the car is close to my liking.

A lot of people ask me why I run a considerably bigger front splitter than rear wing.Well, going back to our most basic load transfer example, the bigger splitter makes400-500 pounds of downforce (front grip) versus the 300-350 that the rear wingmakes (rear grip). The net result is more front grip than rear, which in a perfectly

neutral car would cause oversteer, but in a Subaru just makes it more neutral.

Next time you see a Subaru at the track with a 10-foot wide wing raised to roof leveland a little v-limited lip spoiler, you'll probably laugh now that you understand what

he's actually done to his car.Quote:Originally Posted by thundercamel

I wonder this also. I use the tire squeal to know to not push it any harder, and keepit squealing through the turn (on a track). I had just a little squeal the first time, butI've been pushing it louder the last 2 times.The squeal is your car not wanting to turn, and you either giving it more gas or more

steering input. Now, depending on the tires, this squeal could be AFTER it's alreadyundersteering pretty badly, or when it's just starting. This is why I tell people not to

really use the noise as their indicator.

Now, assuming this noise is the start of understeer for you, hearing the noise isn'tterrible, but you could actually go faster if you got the car to rotate more initiallybefore getting to power. The squeal would go away, you'd be on the gas sooner, and

you'd have a higher exit speed. Depending on the corner, this may be almostimpossible, especially in auto x since it's all understeery, slow, tight corners. Still,brake a little later and get some good trail braking in and you may find that you canstill rotate the car before the apex even in those little 40mph corners that seemimpossible to get through without plowing.Quote:Originally Posted by GotSTI?

I have had 8 hours of track time. 4 hours of class time. All of this was at WatkinsGlen. Since I was new to it I was a novice. Still I was one of the fastest cars on thetrack rarely getting passed my first trip there and never getting passed my secondtrip there. Needless to say, I started getting Mario Andretti complex... thinking I was

better than I was.

When I was at the track I heard people talking about late braking and I kept sayingto myself I know these Brembos can handle me doing that. My first instructor had

me do a lot of early braking whereas the second one did not. That's where I startedto get into some trouble. I saw a lot of the RWD cars braking realllly early. Whichmade me want to brake realllly late. Quite honestly, this practice had me focusing so

hard on timing the braking I wasn't thinking about my shifting and corner entry well.So, I hit the grass and got high up the curbing a couple times. This cost me a fewextra track sessions before my instructor let me drive solo.


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I learned to practice shifting smoothly on the straights so it would be better for theturns. It was too tempting to smash through gears on the straight away when you'd

see a Z06 or something high powered in front of you. When in actuality beingsmooth and hitting the turn right made a bigger difference in catching those typ ofcars.

Now I didn't try trail breaking but found that I could turn in later then other cars. Ifound that tactic built a lot of confidence / straighter lines through the turns. A LOTless worry about going off track too! I came out most turns a lot faster with thistactic. It was my second instructors advice that seemed to make a huge differencewith this. I wonder if you could write your thoughts about this?

Also, I am wondering what is the ideal RPM going into turns for our cars. I found that

most of the time I was in 4th and 5th at Watkins Glen (4th for turns). The only time

I hit third was with slower cars in front of me. However, that generated a ton ofpower... or was it that I was just able to get on it earlier into the turns? It was veryapparent as I got the point by a lot when this happened.

Lastly, how does heel toe work into this? I'm sure that's a whole other topic but I'dlike your explanation on it as I can actually understand you!

Thanks Ben!What you're describing is late apexing. It's always safer, and generally recommendedwhen you're learning a track. The worst that happens is you go a little slower overall

through a corner if you apex way too late. Then when you consider the worst thingthat happens when you early apex is you run straight off the track...late apexing is

the way to go. Generally speaking, the true apex of a corner is not the same thing asthe geometric apex. Most corners require a slightly later apex than the "middle" ifthat makes sense.

The concept is most often referred to as "slow in, fast out." In other words, you

brake a little bit more, you turn in a little bit later, but then you can get on the powerreally hard on the way out because you got most of your turning done in the firsthalf of the corner. As you get more comfortable with trail braking, you can take that"slow in, fast out" concept and turn it in to "fast in, fast out" but it takes a lot ofpractice.

Most people, if not specifically told otherwise, will instinctively go "fast in, slow out"

because they enter a corner too fast, understeer, scrub speed in the corner, andthen get on the gas late at the exit. If you compare your "slow in, fast out" approachwith their "fast in, slow out" you'll always be faster, and that's what you were seeingat the track.

Once you are 100% comfortable with the track (you know the line PERFECTLy) andyou are 100% comfortable with your car and your driving, you can begin to try sometrail braking. Essentially, this lets you carry more speed in to the corner while also

reducing understeer. Yes, you can actually go faster and turn more. Thus the "fast in,fast out" principle.

On to RPM range for entering corners. I'd say 4000-5000 RPM. This gives youenough revs to let the gear wind out and not have to shift in a corner (bad!). On theflip side, I'd recommend shifting around 6500. There is no need to wind it all the wayout to 7200 unless you're on a track where the end of a straight is just perfectly at


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7200 and it would be slower to upshift and immediately downshift. Otherwise, you'rebeing nicer to your motor and actually staying in a better power band (on most

turbos). For example, on the engine I'm building I'll be shifting around 7000-7500even though it's good for 8000-8500. There is just no reason to tempt fate orexcessively stress components like that for little to no gain.

Finally, heal toe. Your heal-toe is done during phase 2 of braking. Phase 1 would beyour primary stopping right at the beginning. Phase 2 is the rest of the stopping youneed to do to make the corner, as well as your downshifting. Phase 3 is your brakerelease.

The reason for heal toe is that during phase 2 your right foot is on the brake, but youalso need to hit the gas to blip the throttle when downshifting (for a rev-matched,

smooth shift). There are two methods for heal toe, one is actual heal-toe (which I

prefer, but most people don't) where you rotate your foot in such a way that yourtoes are on the brake and your heal hits the gas pedal. The more common way is totoe-toe, where you roll your foot across the pedals so the left side of your foot and

your big toe is on the brake, and the right side of your foot hits the gas. This iseasier for people with big feet or when pedals are tightly spaced together. Forwhatever reason, even with my size 12 shoes and fairly narrow pedals, I still prefer

to heal toe as I feel it gives me more control over my braking.Quote:Originally Posted by TorstenWYeah, you're buddy in the Exige that just outbraked you on the inside and is about to

claim position, lol.......

ps; Very nice write-up, btw

.That quote is how to get comfortable with trail braking. When you start applying it ina race setting, you're braking later than that exige, entering the corner faster, and

then getting on the power at almost the same time. The net result is usually a 5mphfaster entry speed with a 10mph faster exit speed on say an 80mph corner.

That exige that late braked on the inside is off-line and is either going to have toforfeit his position, run in to me, or I'll let him in and watch him overshoot the corneras I pass him again on the exit (most common).Quote:

Originally Posted by subyalexAMAZING post, I can't thank you enough or this insight Ben.

Now, if you could, maybe expand on how left foot braking may be able to assist with

keeping the car neutral on long sweepers etc?

I learned alot fro this post, and made me realize how much I have to learn.Some drivers left foot brake, most don't. It's more common in Rally, but you'd be

surprised to find that most track drivers don't bother.

When you think about it, what is left foot braking doing? Decelerating mid corner.

What would lifting off the gas slightly (20%) in a high speed sweeper be doing?Decelerating mid corner. What's the difference? If done properly, none, but you'renot using two feet, and you're not heating up your brakes (not really a concern, butstill a valid point).


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Left foot braking is more of a "sounds cool" kind of thing to do, but in practice, the

results just aren't there (on the track). It's not BAD, but it's not better, and it'sgenerally harder to get comfortable with and is easier to screw up. Once you'vegotten comfortable with being very sensitive with your gas pedal getting on the gas,it's not hard to re-use that sensitivity getting off the gas.

I know a few professional drivers that like to do it, and I know about 5 times asmany that don't like to do it. It's just personal preference. Personally, I'd recommendnot. There are other things you could be learning and concentrating on that wouldmake you go faster .Quote:Originally Posted by tyler_sti

One thing I was going to add is that. If one were to left foot brake in lets say a nice

long 90-100mph right sweeper like big willow. You're entering the turn at either fullor half throttle, at this point if you need to scrub off speed and release off thethrottle you might initiate some over steer because the cars is already loaded on its

left side at a high rate of speed. It dosen't always happen especially if you have goodsuspension, but I've found letting off in mid turn can be very dangerous especiallywithout enough down force on the rear. I like to left foot brake because no only does

it keep me in boost for the exit, but the weight transfer isn't as severe. IMOFirst, even in a stock STI, turn 8 is a 120mph+ corner. If you're lifting or left footbraking at 90-100mph...don't. You should be flat through 8 if you're comfortabledoing it. Aim for the inside of 8 and keep the pedal flat, as you get to the end of 8

release your steering and let the car gently glide out to about 1 car width from theoutside of the track, do your braking in a straight line for 9, and get back on the gas.

With coilovers and any sort of good tires and/or aero, turn 8 quickly becomes a turnthat is more about balls than car capability.

But as for the left foot braking:

There is no difference in load and/or oversteer characteristics between left footbraking and gently reducing throttle. I'm not telling you to LIFT completely, simply ifyou're at 100% throttle, back off to 90%. This is exactly the same thing asremaining at 100% throttle and applying 5-10% brakes, but it requires only one foot.If you're getting oversteer lifting in sweepers, you're lifting too much. You could liftless, go faster, and keep things neutral, if that makes sense.

If it's easier for you to control the deceleration with left foot braking, go for it. It'snot a bad thing. In regards to the "staying in boost" part of it, you shouldn't be liftingto the point that you fall out of boost anyway. Again, if your lift is that severe, that's

why you're getting oversteer. 100% throttle -> 90% or 80% isn't going to drop youout of boost, and you're not going to be waiting for the turbo on the corner exit. Theonly way that would happen is if you lift completely.

Some of the terms you're using are concerning though:Quote:Originally Posted by tyler_sti

You're entering the turn at either full or half throttleThat's a HUGE difference. Which is it? If you're thinking of the gas pedal inincrements of "OFF, HALF, and FULL" you'll benefit greatly by changing how youthink about the gas pedal. There is a significant difference between even 90% and


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100% throttle when you're at the limit, backing off to 50% throttle is like braking interms of load transfer.

Quote:Originally Posted by tyler_stiI've found letting off in mid turn can be very dangerousAgain, letting off or lifting should mean 100% -> 90%, or 70% -> 50%. If you're

thinking of letting off as removing your foot from the gas pedal, yes, that isEXTREMELY dangerous.

The problem with Subarus is people can get away with that kind of stuff and developextremely bad habits. People lift or even brake mid turn, and many times, nothingbad happens. They then start to think that it's OK, and all this crap about drivingsmoothly and making subtle inputs doesn't apply to them. Then they drive a car that

isn't nearly as forgiving (just about anything else besides an Evo or GTR) and have

insane oversteer problems and go spinning off the track.

At the absolute LIMIT, a Subaru doesn't behave much differently than those "other"

cars that are considerably more sensitive to load transfer and throttle input. However,until you get within about 5% of that limit, it's almost like the rules of driving don'teven apply to an STI (they just understeer). In a normal car, these rules start to

apply when you get within about 40% of the limit.__________________Ben FriedRealityDesign

- 2008 Silver BMW 135i

- 2010 Team RD #027 Lotus 2-Eleven Race Car________________________________________

Quote:

Originally Posted by Chris05STiIt was like your were in my head! Very good info, makes sense. We should have aForza 3 meeting online for this!

Indeed. It's actually fun to mess with in Forza. One of the biggest things you canimprove in that game is not mashing the joystick all the way to one side. The sameconcept applies in that game, if you push the joystick all the way to one side (full

steering lock) you're asking your tires to turn more than they need to and causingundersteer.Quote:Originally Posted by severe

well yeah my initial braking is really hard, i found this to help my times sometimes iget a single chirp from the abs kickin in also. i havent been to the track yet but myseat time is mainly in autox and im pretty much learning.

i generally slam them hard right before the turn, but reading your post i realize whati never do is release them smoothly. i just drop the brake pedal and then get my footon the gas. i dont slam the gas i have a pretty good feel for the throttle and how the

car reacts to minute adjustments mid turn.

based on what you wrote though it seems like i should take a split second longer inmy brake release. i dont know how practical it will be since our autox setups are


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generally really tight and technical but its worthwhile to try and see if it'll help mytimes.

right now i can rotate the car a tiny bit with just throttle if i have the dif set to open,and it has some very slight understeer if i'm accelerating through the turn 1 notch up.

btw this has been on my mind, im generally screeching my tires around the entirecourse. i keep wondering if this is slowing me down or not. its right at the thresholdusually i.e. if i remove a very small amount of steering input the screech goes away.i noticed most other guys aren't so aggresive though (though most of them alsohave rwd)Two things here. First, this obviously matters a lot more at the track than at an autocross, but the concept can still be applied. No matter what corner you're talking, a

little trail braking will benefit your Subaru. It's just going to be an even quicker brake

release in auto x because you brake considerably less and you're not going fastenough to be able to really get on the pedal hard without the ABS coming on.

As for tire screech, try not to rely on that. It's more of a crutch than anything. Reallygood r-compounds and any slick are completely silent. You don't hear any noise atall until you're backwards. The same goes with lockup / ABS, they don't chirp, you're

just see silent tire smoke in your rear view (or in front of you in an open wheel car ).

The key is to feel that understeer coming on BEFORE the tires have to tell you aboutit. First, because if you correct it really early or avoid it altogether, you'll go much

faster. The second reason is obviously as you get better tires you'll stop getting thataudible warning. Now, with street tires and street suspension, you still have plenty of

time to correct if you wait too long because everything is somewhat in slow motion.If you go to a stiffer, lighter car with stickier tires, everything happens much faster.Quote:Originally Posted by santacruz02Ben, I'd assume the size or width of the front tires makes a difference as well. Like

possibly understeer was cause from not having enough tire to pavement?This actually makes no difference, unless you're suggesting running a DIFFERENTsize tire in the front versus the rear. Whether you have 225's on all four corners or315's you're still going to have identical understeer characteristics basically. The onlydifference is you'll get it at a slightly higher speed, but when the grip is still going togive up at the same point in the same fashion.

When you see cars with wider tires in the back than the front, they do this toartificially reduce front grip to compensate for oversteer problems. This is particularlynoticeable in a Porsche.

You can actually mess with this in the opposite direction with a Subaru and it's kindof fun. Like running 245's in the front and 225's in the back, assuming you can find atire with the same overall diameter as to not slowly destroy your center diff. Anotherway to toy with this is to run new tires on the front and used tires on the rear. I used

to do this quite a bit, but just know that if you trail brake now, you'll DEFINITELY getoversteer.

Also, please keep in mind when I'm talking about new and used tires I'm talkingabout race tires, so the difference at most is 2/32's tire depth. If you put new streettires and almost bald street tires you'd probably have a 5/32's difference which isn'tso great for your center diff.


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Last but not least, and the easiest thing to adjust, is your tire pressures. Running

more pressure in the rear than the front will also help make the car more neutral, ormore oversteer prone after aggressive trail braking.

Obviously you can adjust suspension settings, swaybar settings, etc, but I like to go

to them last for the fine tuning. I'll first start out with what makes the biggestdifference (tires), then move on to aero (adjust rear downforce), and then move onto the suspension when the car is close to my liking.

A lot of people ask me why I run a considerably bigger front splitter than rear wing.Well, going back to our most basic load transfer example, the bigger splitter makes400-500 pounds of downforce (front grip) versus the 300-350 that the rear wing

makes (rear grip). The net result is more front grip than rear, which in a perfectly

neutral car would cause oversteer, but in a Subaru just makes it more neutral.

Next time you see a Subaru at the track with a 10-foot wide wing raised to roof level

and a little v-limited lip spoiler, you'll probably laugh now that you understand whathe's actually done to his car.Quote:

Originally Posted by thundercamelI wonder this also. I use the tire squeal to know to not push it any harder, and keepit squealing through the turn (on a track). I had just a little squeal the first time, butI've been pushing it louder the last 2 times.

The squeal is your car not wanting to turn, and you either giving it more gas or moresteering input. Now, depending on the tires, this squeal could be AFTER it's already

understeering pretty badly, or when it's just starting. This is why I tell people not toreally use the noise as their indicator.

Now, assuming this noise is the start of understeer for you, hearing the noise isn'tterrible, but you could actually go faster if you got the car to rotate more initially

before getting to power. The squeal would go away, you'd be on the gas sooner, andyou'd have a higher exit speed. Depending on the corner, this may be almostimpossible, especially in auto x since it's all understeery, slow, tight corners. Still,brake a little later and get some good trail braking in and you may find that you canstill rotate the car before the apex even in those little 40mph corners that seemimpossible to get through without plowing.Quote:

Originally Posted by GotSTI?I have had 8 hours of track time. 4 hours of class time. All of this was at WatkinsGlen. Since I was new to it I was a novice. Still I was one of the fastest cars on thetrack rarely getting passed my first trip there and never getting passed my second

trip there. Needless to say, I started getting Mario Andretti complex... thinking I wasbetter than I was.

When I was at the track I heard people talking about late braking and I kept saying

to myself I know these Brembos can handle me doing that. My first instructor hadme do a lot of early braking whereas the second one did not. That's where I startedto get into some trouble. I saw a lot of the RWD cars braking realllly early. Which

made me want to brake realllly late. Quite honestly, this practice had me focusing sohard on timing the braking I wasn't thinking about my shifting and corner entry well.So, I hit the grass and got high up the curbing a couple times. This cost me a fewextra track sessions before my instructor let me drive solo.


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I learned to practice shifting smoothly on the straights so it would be better for the

turns. It was too tempting to smash through gears on the straight away when you'dsee a Z06 or something high powered in front of you. When in actuality beingsmooth and hitting the turn right made a bigger difference in catching those typ ofcars.

Now I didn't try trail breaking but found that I could turn in later then other cars. Ifound that tactic built a lot of confidence / straighter lines through the turns. A LOTless worry about going off track too! I came out most turns a lot faster with thistactic. It was my second instructors advice that seemed to make a huge differencewith this. I wonder if you could write your thoughts about this?

Also, I am wondering what is the ideal RPM going into turns for our cars. I found that

most of the time I was in 4th and 5th at Watkins Glen (4th for turns). The only timeI hit third was with slower cars in front of me. However, that generated a ton ofpower... or was it that I was just able to get on it earlier into the turns? It was very

apparent as I got the point by a lot when this happened.

Lastly, how does heel toe work into this? I'm sure that's a whole other topic but I'd

like your explanation on it as I can actually understand you!

Thanks Ben!What you're describing is late apexing. It's always safer, and generally recommended

when you're learning a track. The worst that happens is you go a little slower overallthrough a corner if you apex way too late. Then when you consider the worst thing

that happens when you early apex is you run straight off the track...late apexing isthe way to go. Generally speaking, the true apex of a corner is not the same thing asthe geometric apex. Most corners require a slightly later apex than the "middle" ifthat makes sense.

The concept is most often referred to as "slow in, fast out." In other words, youbrake a little bit more, you turn in a little bit later, but then you can get on the powerreally hard on the way out because you got most of your turning done in the firsthalf of the corner. As you get more comfortable with trail braking, you can take that"slow in, fast out" concept and turn it in to "fast in, fast out" but it takes a lot ofpractice.

Most people, if not specifically told otherwise, will instinctively go "fast in, slow out"because they enter a corner too fast, understeer, scrub speed in the corner, andthen get on the gas late at the exit. If you compare your "slow in, fast out" approachwith their "fast in, slow out" you'll always be faster, and that's what you were seeing

at the track.

Once you are 100% comfortable with the track (you know the line PERFECTLy) andyou are 100% comfortable with your car and your driving, you can begin to try some

trail braking. Essentially, this lets you carry more speed in to the corner while alsoreducing understeer. Yes, you can actually go faster and turn more. Thus the "fast in,fast out" principle.

On to RPM range for entering corners. I'd say 4000-5000 RPM. This gives youenough revs to let the gear wind out and not have to shift in a corner (bad!). On theflip side, I'd recommend shifting around 6500. There is no need to wind it all the way


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out to 7200 unless you're on a track where the end of a straight is just perfectly at7200 and it would be slower to upshift and immediately downshift. Otherwise, you're

being nicer to your motor and actually staying in a better power band (on mostturbos). For example, on the engine I'm building I'll be shifting around 7000-7500even though it's good for 8000-8500. There is just no reason to tempt fate orexcessively stress components like that for little to no gain.

Finally, heal toe. Your heal-toe is done during phase 2 of braking. Phase 1 would beyour primary stopping right at the beginning. Phase 2 is the rest of the stopping youneed to do to make the corner, as well as your downshifting. Phase 3 is your brakerelease.

The reason for heal toe is that during phase 2 your right foot is on the brake, but you

also need to hit the gas to blip the throttle when downshifting (for a rev-matched,

smooth shift). There are two methods for heal toe, one is actual heal-toe (which Iprefer, but most people don't) where you rotate your foot in such a way that yourtoes are on the brake and your heal hits the gas pedal. The more common way is to

toe-toe, where you roll your foot across the pedals so the left side of your foot andyour big toe is on the brake, and the right side of your foot hits the gas. This iseasier for people with big feet or when pedals are tightly spaced together. For

whatever reason, even with my size 12 shoes and fairly narrow pedals, I still preferto heal toe as I feel it gives me more control over my braking.Quote:Originally Posted by TorstenW

Yeah, you're buddy in the Exige that just outbraked you on the inside and is about toclaim position, lol.......

ps; Very nice write-up, btw

.That quote is how to get comfortable with trail braking. When you start applying it in

a race setting, you're braking later than that exige, entering the corner faster, andthen getting on the power at almost the same time. The net result is usually a 5mphfaster entry speed with a 10mph faster exit speed on say an 80mph corner.

That exige that late braked on the inside is off-line and is either going to have toforfeit his position, run in to me, or I'll let him in and watch him overshoot the corneras I pass him again on the exit (most common).

__________________Ben FriedRealityDesign

- 2008 Silver BMW 135i- 2010 Team RD #027 Lotus 2-Eleven Race Car

Quote:

Originally Posted by subyalexAMAZING post, I can't thank you enough or this insight Ben.

Now, if you could, maybe expand on how left foot braking may be able to assist withkeeping the car neutral on long sweepers etc?

I learned alot fro this post, and made me realize how much I have to learn.


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Some drivers left foot brake, most don't. It's more common in Rally, but you'd besurprised to find that most track drivers don't bother.

When you think about it, what is left foot braking doing? Decelerating mid corner.What would lifting off the gas slightly (20%) in a high speed sweeper be doing?Decelerating mid corner. What's the difference? If done properly, none, but you're

not using two feet, and you're not heating up your brakes (not really a concern, butstill a valid point).

Left foot braking is more of a "sounds cool" kind of thing to do, but in practice, theresults just aren't there (on the track). It's not BAD, but it's not better, and it'sgenerally harder to get comfortable with and is easier to screw up. Once you'vegotten comfortable with being very sensitive with your gas pedal getting on the gas,

it's not hard to re-use that sensitivity getting off the gas.

I know a few professional drivers that like to do it, and I know about 5 times asmany that don't like to do it. It's just personal preference. Personally, I'd recommend

not. There are other things you could be learning and concentrating on that wouldmake you go faster .

the real truth about under steer

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