Heel and Toe?

[GRiDRaceTech]

Well, there's a certain slip angle (the angle of the tire's path to the car's true path, in a very simple nutshell) range through which the tire operates at its peak. (6-10 degrees for most race and high-performance street tires, usually) Below that range, the tire is being under-used and is not delivering full grip. Above that range, the tire is being over-used and is not delivering full grip. We consider over-use to be a fully sliding condition. In truth, the fastest way around a track is in a very subtle four-wheel slide around every corner to utilize the tires to their fullest. If the front tires are at a higher slip angle than the rear, then the car is understeering; if the rear tires are at a higher slip angle, then the car is oversteering.

Thus, drifting/excessive oversteer is not usually faster than grip except in instances when understeer is severe. (Very tight turns, mostly) I use initial oversteer to rotate my car and get it pointed the right way, and to overcome understeer.

Confuscious say: Tire sliding ever so much faster than tire gripping absolutely or sliding greatly.

[Thai Juku]

I heel-toe my integra sometimes...It's easy for me, not that helps any of you...Anyway, it's all about the rhythm and going into for me, don't know about you guys. I wear size 9 iverson 3 basketball shoes, its a fairly wide shoe. It can cover the brake and gas pretty well. I guess thats all I can say about it...


*I didn't read any of the posts up above when I typed this cuz, I'm lazy...

[Craftsman]

yea, your traction Radius is much greater when you're not sliding. Therefore you can apply more power to the pavement.

Drifting is not faster than non-drifting. The only case where this is not true is on decreasing radius turns. If you can do a perfect drift, decreasing raduis turns are faster done sideways because of the nature of the turn, but anything like increasing radius, or S-turns, drifting is only going to add precious seconds to your time.

Going back to the traction circle, you can carry more speed when you're within the static traction circle. When you're drifting, the traction circle decreases by 10-20%.

Matt.

[GRiDRaceTech]

Actually, if you had read the above post carefully, you would've realized that the fastest way to go around a track is slightly sliding.

The traction circle's outermost limit is the absolute maximum of a tire's traction. It is also a sliding state when talking about the lateral acceleration axis, also known as cornering. It is a rolling state in the braking and moving acceleration axis. (In acceleration from a stop, it's a very very subtle slip, which then becomes a rolling state) When using very large slip angles, just like Craftsman said, the tire is making much less grip than using very small slip angles. I'll get some diagrams up sometime within the week to explain this better.

[malcolm]

also, even when you are "gripping" totally in a corner, there is still some slip to the tire (unless you have perfect four-wheel steering).

also, it's usually only for medium to lower speed corners where a slight drift upon entry will help you. The car rotates, so you don't have to use as much energy to rotate the car mid corner, and you can use more to accelerate. If you know a lot about the traction circle, you'll know that if you have less steering to do, you can accelerate harder (reducing the lateral force vector, and thus being able to increase the longitudinal force vector without breaking traction).

I did a lot of this on the weekend. I was driving a car with a locked rear end, and it had a tendency to want to understeer, especially in slow corners. The team-owner wanted me to go about 2 tenths faster, so I thought about applying that logic in a place I hadn't thought of before. I found that trail-braking with that car required a different technique... I had to just keep minimal brake pressure on during turn in, and I was able to break the rear end loose on entry. As I approached the apex, I was able to get on the throttle well before the apex, and accelerate through the corner (and therefore have a killer run up a long, uphill straight). That likely accounted for 4 of the six tenths I was able to improve the next day.

anyway, here's a thoery I had that I posted on another forum: (just some thoughts going through my head...)

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the "edge" is not really an edge so-to speak. It is more like a line. the closer you are to the line, the faster you will go. If you are always a certain amount away from that line, whether before it or beyond it, you will lose the same amount of time (doing an all out drift will be as slow as only pushing to 80% of the limit).

The way I look at it is like it is a sine curve, as seen below. The "amplitude" is the distance between the dark, horizontal line with numbers on it and the various curves.



In my theory, the absolute highest amount of grip will be on that black horizontal line. Of course, that would be perfect, which is virtually impossible. Anyone can take a car to the limit, but if they are not smooth, then their car will constantly be going over the limit and under the limit erratically, illustrated by the green line. The smoother the driver, the straighter that line will be, like the purple line.

Now, we bring in friction. A tire in total grip will be able to extert a higher force on the road than one that is slipping (think about when you are stuck in the snow... your best bet is to feed in the throttle slowly, not mash it to the floor and spin the tires at 150 km/h).

If a driver is right on the limit of adhesion, then when he pushes it beyond that limit, the car breaks loose, then it gains traction, etc, etc. Therefore his level of grip is going up and down, thus making it harder to control, and likely slower. Now if he pushes just a *little* harder so the "bottom of his sine curve" is just slightly above that limit (ie. a slight drift), then he can be smoother, because there is the same amount of grip throughout the corner. Rather than suddenly gaining and losing traction as he goes through the corner, he has the same traction all the way through. With varying traction, the sidewalls of the tires are flexing, the suspension is moving, and the car is upset, so the actual grip level of the tire is most likely lowered anyway. With a slight drift, everything is constant, so the actual grip level of the tire is likely higher (ie. no flexing tires, no moving suspension, and the car is stable).

So, according to my theory, a slight drift is theoretically slower, because you have less total traction. However, in practice, a slight drift is faster 99% of the time because the driver is only dealing with one grip level, and it keeps the car more stable. This technique can be used in pretty much all corners, whether initiated by trail-braking, or just allowing the tail to come out under power.

Also, with a slight drift, if it begins to understeer, you can quickly lift off the throttle, which will loosen the rear, and give the front more grip. If you were just gripping, and it began to understeer, now you have to stop your front tires from sliding and bring them to a grip situation, and take your rear tires from a grip situation, and begin to slide them. This would require a very harsh lift of the throttle and would upset the car way more than you would need to if the car was already drifting. The other option would be to let off the throttle gently, and straighten out the front wheels. Now you have slowed down, missed your apex (by about half a car width or more), and now you're in the marbles with your outside tires... Major loss of time.

There is yet more to add to the debate. It takes energy to rotate the car. Michael Schumacher and Ayrton Senna were masters at rotating the car before the apex of the corner, so less actual turning needed to be done. Essentially, they would drift the car toward the apex, the car would stop drifting around the apex, and then they could grip out of the corner, thus using the increased traction from the tire gripping. I have used it to some success on some corners in the Corvette and the Radical. You can get a lof the rotation out of the way before the corner, all while slowing down the car all the way to the apex (which means you can go deeper into the corner). It's not something that most drivers can do straight out of the box, but with practice, it is an excellent technique that can allow you to go later on the brakes, and get a better run out of the corner. This also shows that drifting can be slightly faster with this technique, used mainly in medium to slow speed corners.

So yeah, I'd say drifting is faster.

[marshun]

talk about beating a dead horse man.

[malcolm]

yeah, I guess... I just thought I would answer his question, using minimal effort (ie. posting stuff I've already written before). :P

[marshun]

[RyanHampton]

So no driftring is not faster if you are a good driver. overcoming the slip angles in any sense is slower period. If you stay at 99% of the tires total grip you will be faster. I have been racing cars for a long time, and if you "drift" the car you will be slower. Do not confuse the fact. You are talking about things that most people even in drifting cannot do. The only time in racing I try to drift a car is in an extremely low speed corner. Yes it is true if you are on the limit you are constantly going over and under that maximun of the tires total grip. If you are a good driver like you say you can keep that car at 99% of total grip. So drifting is slower.


Ryan Hampton

[malcolm]

ryan, I started racing two years after you did. I don't have the budget that you had to do something like Barber Dodge, or any open-wheel racing, so I've been just regional racing in Canada. So far, I've been asked by three teams to race for them this year (sports car racing), but I am mostly just racing the Corvette my father and I run. That must mean I am doing something right.

I find that drifting on the entry to slow to medium speed corners can help my exit speed, especially with cars that tend to understeer (ie. ones with locked diffs, etc).

You do realize, Ryan, that every tire is slipping to a small degree when you turn, don't you? Most cars don't have perfect four wheel steering, so the rear wheels won't be perpendicular to a line going from the axis of the car to the centre of the turning circle. That means that the rear tires must slip very slightly anyway. If the tires are slipping already, then they already have a lower coefficient of friction (the dynamic coefficient of friction).

Also, you say that a good driver can take a car to 99%... what if there is a slight crack in the pavement, or a little bump? all of a sudden, the car's ultimate limit of traction is reduced, and it starts to either understeer or oversteer... now, if the car was in a slight drift (ie. maybe 2 or 3 degrees of yaw, at the most), the car would only be a little upset. If the car was actually "gripping" then it would slide. The road is exerting less force on the tires now, so the attitude of the car changes... The suspension rebounds on the outside, and the sidewalls of the tire flex less... And if you do regain traction, then your suspension compresses again, your tires flex again... if this happens too harsh, you'll lose traction again. This is a tankslapper. You've just lost a lot of time.


(this may be a little disjointed, because I was interupted a few times... haha)

[GRiDRaceTech]

Interesting and completely valid point raised, malcolm. When in a slight drift, the car's composure isn't upset as much by bumps because it is already sliding.

I've noticed that while sliding into my street... there's a dip there, and if I go in normally the car gets unsettled, but if I go in sliding a bit, the car is fine.

[RyanHampton]

Yes in fact it is true there is always slight bumps, cracks and other things in the road. However the slip angle of a racing radial tire is in the 1% to 3% range, beyond that you are losing time. With a bias-ply racing slick it is a 3 to4% slip angle. In a street / high performance tire you have a much bigger window say 6 to 8%. If you have raced on a true radial slick you would soon realize that drifting is not faster, and you would not have tires after too long. I have raced on both, and you do hear a lot of tire noise on a street/ performance tire, but go race on a slick, you hear nothing. If you do slide, your window is very small between having grip and not having grip. It comes down to simply watching a race on tv. If drifting was faster, they would be doing it. I have been a tire tester for Firestone for 2 years so I do speak with some authority on the subject. Now if you ask me if drifting is more fun, I would agree completely!! Interesting points though, I just don't want people getting misinformed of the wrong things. You are correct about the very slight slip angle being faster on a street tire, but there are very few people that can hold it there, or use it effectively to go faster. And beyond that if drifting was faster why do they have traction control on Formula 1 and Champ Cars? Why because grip is faster....just another question.....Now if you have a car in a 4 wheel drift that means you have overcome the traction point of all four tires, that is not drifting that is mearly driving beyond the limit of all four tires. Now in the laws of physics friction equals heat and a loss of energy once again.... tire rolling is faster than tire sliding. Once again loss of energy equals loss of speed.

[malcolm]

However the slip angle of a racing radial tire is in the 1% to 3% range, beyond that you are losing time. With a bias-ply racing slick it is a 3 to4% slip angle. In a street / high performance tire you have a much bigger window say 6 to 8%.

I wasn't saying that full-opposite lock is fast... :P You're just saying what I said earlier about having a very slight slip angle.

If you have raced on a true radial slick you would soon realize that drifting is not faster, and you would not have tires after too long

Drifting all the way through the corner, perhaps, but I was talking mainly on entry to assist the car in rotation prior to the apex. I currently race a Corvette C5 on radial slicks, and raced an older Corvette ('79 Trans-Am car) on bias-ply slicks. The car with the bias-ply tires responded well to slightly more slip angles on entry to the corner than the radial tire'd car, but still, I was able to improve my time by using each.

And beyond that if drifting was faster why do they have traction control on Formula 1 and Champ Cars?

That's for acceleration, and if you've ever heard about their set-ups, you'll know that they have different settings to allow the tire to slip just a little bit.

Also, Michael Schumacher always drifts the car (ever so slightly) on entry to medium to slow speed corners, and takes an earlier apex, yet somehow manages to get a faster run out of the corner. The team has said in the past that he and Ayrton Senna have been the only ones to be able to have their fastest time be faster than the computer model, because they can't model their styles.

I'm not saying that I'm up there with those guys, as Formula cars would be a little more tricky to drift on entry than a big GT car... :P

[RyanHampton]

Goog points. We are saying the same thing. When I raced the bias ply tire in F2000, you should rotate the car on entry. Especially with the side wall deflection and making the tire take a set. However on an IRL car with radials, you want no slip whatsoever. Thats because you want no wall contact, cause it hurts. All I am saying the only time you would use drifting is in low speed corners to rotate the car. High speed corners you want no slip in the car. Cause rolling is faster. Now I do know that tires are slipping all the time, you can't avoid that. However if you can keep the tire from slipping and keep the tire at 100% traction it will be faster. If you look at a tight turn compared to the wheelbase of the car, sometimes it will be faster to rotate the car and get on the gas sooner. When I drove the F2000 cars my nick name was asses and elbows, because I used to drift into the corners. Now we need to define "drifting"... I do not consider rotating the car "Drifting". The problem with saying drifting is faster is you will get these people that watch too much intial D, and they think that is faster than "Grip" driving. I consider the best drivers in the world to be the guys that can adapt to any car, From oversteer to understeer you can manipulate the car to do anything you want, that is what makes a good driver not drifting, or griping. It all depends on the situation. So I guess if you define drifting as slight oversteer you could say it is faster in low speed corners. However, if you make it in to ALMS be sure you drift the 150mph kink at Road America it ought to be fun. Good points and good luck in your racing..

[malcolm]

I figured we'd be on the same page... haha. I totally agree that in a situation with IRL cars with concrete inches away, I would be a little hesitant to try to rotate the car on entry to turn three at Charlotte...

I agree that the term "drifting" has become a misnomer... I am used to the pre-initial-d days (never seen initial-d, no desire to). Back then, a drift was ever-so-slight oversteer (like the 2% slip we talked about), and anything more than that was a slide... "show drifts" are slow, but slight "four-wheel-drifting" can be fast, if executed properly.

Also, once you get into cars with aero, then you lose downforce as the yaw increases... I heard that F1 cars lose 50% of their downforce at five degrees of yaw. The car can step out a little bit, but if it goes beyond that, then all of a sudden, you're just gone... and into the wall.

It's hard to say that there's one technique that's guaranteed to make everyone go faster, because so many cars have so many different traits. I agree with you, the best drivers are the ones where they don't need to adapt the car to them, but they can adapt to the car. I strive towards that, and before I make a set-up change, I try to overcome it myself by trying different things (left-foot braking, trail-braking, tapping the throttle mid corner... these are ones I use when the car is understeering). This will hopefully help in endurance racing, when the car is never perfect.

Thanks man, and good luck with your racing and drifting too... Looks like you're doing quite well so far.