now you see Tiff was 'drifting' the E30; that's all 4 wheels

[JimmyC]

an ards video - wow... video hadn't been invented when I took mine

get a DVD aswell now old man

[kam-325i]

So all 4 wheels are not slipping, they are still acting against the mass of the car trying to rotate around its axis.

A tyre will have grip/friction or no grip/friction ?

[orangecurry]

So all 4 wheels are not slipping, they are still acting against the mass of the car trying to rotate around its axis.

A tyre will have grip/friction or no grip/friction ?

erm yes they are slipping because they are moving sideways/laterally
surely we all agree on that definition?

a tyre maintains EXACTLY the same amount of grip (at the same temperature) but the lateral (or if driven the FORWARD) force varies, the lateral say as you go round a corner which tightens, and if driven the amount your foot is pressed into the Axminster.

DVD? eh? whassat sonny?

[M3Compact]

Karan is right imo, controlling the car purposefully when it's out of line is a drift.

Check my tyre contact patches on this right hand hairpin. (forest suspension with tarmac tyres).



Same corner, a year and 20 yards earlier.



The car is in a 'power slide' and a 'drift' too, if there was enough 'free area' or steering lock, the fronts would be rolling in a straight line, even so, it's still a drift imo.

Surely if the cars out of line, it's drifting? (Irrespective of how it's provoked, but 'donuts' aren't drifting imo. )

Agree with much respect for early racers, driving 4 wheel drifts over the edge of the understeer limit, scarey 5hit.

Also agree about 4WD 4WDrifting, pi55ball with a poor surface.

[kam-325i]

God i hate car dynamics......Im doing my own head in......

I would need to see a video of "4 wheel Drifting" to grasp the concept.

My mind is to logical....

Car mass rotaintg around axis, rear wheels providing forward momentum, Causing the rotaion of the mass about its axis to become an arc ?

[orangecurry]

nice pictures

I think I agree with what you are saying - if you mean you are rotating the steering wheel to maintain your angle of 'powerslide', and therefore your front wheels are not always pointing in the direction of travel, I.E. they are SLIPPING laterally, that is drifting.

If you are just pulling out of a corner and the back end steps out, that's NOT drifting.

The distinction I am trying to make is between these two very different levels of driving skill.

[kam-325i]

The " Opps to much throttle" off an island slide is not a drift, but oversteer.

A drift ( I think) would be started on the braking phase of entering a corner, and then carried on through out the corner using the throttle.

[herman]

The car will corner with all wheels straight, the turn is controlled by the throttle.

Correct, not to be confused with a corrected oversteer slide, re escourt.

Fangio, in the 50's power slided past Collins and Hawthorn to win a GP. The wheels are straight but the car moves sideways using the whole of the road and sets you up for the next corner.

You set your steering up, then not turning the, apply throttle and it power slides.

[orangecurry]

The car will corner with all wheels straight, the turn is controlled by the throttle.

Correct, not to be confused with a corrected oversteer slide, re escourt.

Fangio, in the 50's power slided past Collins and Hawthorn to win a GP. The wheels are straight but the car moves sideways using the whole of the road and sets you up for the next corner.

You set your steering up, then not turning the, apply throttle and it power slides.

yes exactly (much better put than my ramblings), but '... apply throttle and it DRIFTS'

[M3Compact]

..... - if you mean you are rotating the steering wheel to maintain your angle of 'powerslide', and therefore your front wheels are not always pointing in the direction of travel, I.E. they are SLIPPING laterally, that is drifting.

That's what I meant.

If you are just pulling out of a corner and the back end steps out, that's NOT drifting.

The distinction I am trying to make is between these two very different levels of driving skill.

Agreed, stepping the tail out on corner exit isn't drifting.

A big, long controlled power slide is drifting tho imo, even if it's in a wide open area.

[herman]

It's not as hard as it sounds, on a track day with my e36 328i. I had instruction, he showed me, then when I did it he was giving me tips. As you go into a corner in the middle of the track, set you steering and push the pedal and it moves sideways with G force. You want turn but you got to keep it still cause the tyres are bent over in that direction. If you twitch it you de-stable the car. i tried to turn and he was slapping my hads shouting still

[M3Compact]

The car will corner with all wheels straight, the turn is controlled by the throttle.

Correct, not to be confused with a corrected oversteer slide, re escourt.

Fangio, in the 50's power slided past Collins and Hawthorn to win a GP. The wheels are straight but the car moves sideways using the whole of the road and sets you up for the next corner.

You set your steering up, then not turning the, apply throttle and it power slides.

Agreed, that's what I referred to as a 'drift over the edge of the understeer limit', cheating a bit to steer with the throttle tho'.

If it's in a 4 wheel drift and you can actually steer it with the throttle, it has to be oversteering.

If you're just controlling the way it turns in with the throttle, it's understeering and not 'drifting'.

[Davenotouring]

It's not a 100% loss of grip.

[astondg]

I have been in a 4 wheel drift in an AWD car, which like people said is easy to get into and control, and also once or twice on the dirt at autocross in my 323i I think. Normally it is powersliding out of the corners (with only a small angle if I want to be quick in my car) but there have been times when I have come out of the corner with the car sliding to the edge of the track but not requiring any opposite lock. It is rare and unintentional but has happened.

I have also once been sideways around a long corner near my house in the wet in an older car with an open diff that didn't require opposite lock but that wasn't a 4 wheel drift. I think because of the open diff it didn't go sideways like my 323i does but I could feel it sliding (just a tiny bit) and I had the steering wheel centered but I was still travelling around the corner for a few seconds but then I had to flick on a little bit of opposite lock at the exit to get it to straighten up. That was just a normal oversteer slide.

Aston

[herman]

Yep, if you get the power down quicker out of a corner, faster lap. 4 wheel drift means you have power on and quicker out. Oversteer out of a corner looks good but slows you down, unless your linning it up for the nect corner as in rally.

[orangecurry]

Yep, if you get the power down quicker out of a corner, faster lap. 4 wheel drift means you have power on and quicker out. Oversteer out of a corner looks good but slows you down, unless your linning it up for the nect corner as in rally.

again exactly what I meant (you should write a guide!)

Karting is an easy example; loads of times I have followed someone overdoing it into a corner and I've drifted round maintaining the speed and then overtaken them

I agree that the 1950s racing drivers are the real heroes, where power and weight were much greater than the grip available at the time (from the narrow tyres and harder rubber), so it took much MUCH more skill to win.

[Bob_S]

and after 2 pages I'm still clueless as to what drifting really is!

A drift implies sideways movement, but a slide also implies this.

Where do you draw the line? I thought drifting was a controlled technique but if all 4 wheels are sliding you are not really in control as you have no grip.
I see a drift is like a powerslide the direction can be controlled by steering and throttle?

p.s I'm unwell

[Skip]

I see a drift is like a powerslide the direction can be controlled by steering and throttle?

It can be..

To be honest I just see this thread as a wind up - drifting is what you want it to be in some ways - watch the Drift Bible and see all the different ways that Keiichi Tsuchiya makes his way "drifting" around a corner - as long as the back wheels have broken traction then you are in some form of drift... thats what I beleive anyway!

[herman]

To see is to understand, to do thrilling, not a wind up. Set the car for the corner in the middle of track, put throttle down. G force pulls you to the outside of the track. The 4 tyres bend in away from G force, power pushes you forward and sideways at the same time. Crabing in a way, all under control. You come out of the corner at the edge of the track, Then more power

[JimmyC]

Theres 2 things here, drifting as most here identify- sideways hooning

4 wheel drift- professional racing technique, a master can corner with out the use of the steering wheel, fully in control

[astondg]

but if all 4 wheels are sliding you are not really in control as you have no grip.

Even when tyres are sliding or spinning they still have some grip, they don't loose grip completely. This is especially true for road tyres and I read a thread about this recently on another forum. Someone there was making a physics model for a car game and he had a lot of information about tyres that had been tested. It showed that once most tyres started to slip there grip level usually plataued (or fell of just a little bit and then plataued) for a while and only started decreasing once the angle got fairly big. Some tyres didn't even reach there peak grip level until they were sliping slightly and this is probably true of some of the tyres they used to used in the old days which is one of the reasons why 4 wheel drifting would have been quicker.

Race tyres are different and they tend to loose grip quickly after there peak and when they start to slip which is one reason race cars are a lot harder to control when you get it wrong and they can be a bit "twitchy" (it is also to do with suspension setups).

Aston

[orangecurry]

truly excellent guys.... now who is going to summarise all this and write it up for the tech section?

(and where is the emoticon for everyone throwing their beer cans at me?)

[Stevin]

As Aston says. proper drifting is getting the car sideways before the corner.

drifting is holding a slide////

if u can get it sideways before the corner..... u r skilled

Hey I'm skilled ... but then I've also lost it a few times doing that, I think it's pretty easy to get it out b4 the corner. Little scandinavian flick, and if it's a rough road add in a touch of hand brake, then the back end comes out, and it's all a case of throttle control, and counter steer

But I'm gonna say this, I'm no pro... my car used to have the battle scars to prove it, now I keep my drifting to where there are no pavements, or trees, or poles

[hoshy]

As Aston says. proper drifting is getting the car sideways before the corner.

drifting is holding a slide////

if u can get it sideways before the corner..... u r skilled

Hey I'm skilled ... but then I've also lost it a few times doing that, I think it's pretty easy to get it out b4 the corner. Little scandinavian flick, and if it's a rough road add in a touch of hand brake, then the back end comes out, and it's all a case of throttle control, and counter steer

But I'm gonna say this, I'm no pro... my car used to have the battle scars to prove it, now I keep my drifting to where there are no pavements, or trees, or poles

I'm not saying I can get it sideways before the corner. But that's what I will aspire to when my car and skill are ready.

hehe, I've got plenty of battle scares and hero damage

[jaistanley]

This one might upset things:

Under steer is understeer.
Over steer is understeer.
Drifting promotes oversteer.

Think about a car driving in a tight(ish) circle just up to but not beyond it's ultimate lateral grip (tyres not really squealing and no 'skidding'), it is behaving as it would mid corner.

Imagine the car is driving on a circle painted on the floor. If he then speeds and the front tyres 'skid' or go beyond the point of grip, the car car be imagined to be driving on a different circle, one deviating from the first and with a larger radius. This we consider understeer.

Now imagine the same scenario but when the driver speeds up, the rear tyres go beyond their ultimate grip and deviate from the smaller circle. When the driver corrects this by turning the wheels in the direction of the slide, the course the front wheels take also deviates from the original, intended, circle. Thus over steer is understeer.

Drifting comes about from a slightly different scenario. Same car, same intended circle but this time when the car gets faster the lateral G on the car pulls all four tyres beyond their ultimate grip. The slip angle between the direction of the tyres tread (the intended route) and the motion of the road (the actual route) increases. To counteract this the driver applies throttle. The spinning wheel then has a component of grip, a component of slip and a new force toward the inside of our big circle generated by the slipping rubber. This in turn brings the car back to it's intended or tighter circle and is oversteer.

This would have been much easier to try and explain if I'd drawn some diagrams or scanned them from my vechicle dynamics textbook....

Does anyone get what I mean. Took a while to get it myself!

I agree that understeer is when you turn the wheel, the fronts slip and you dont go where you want. My old fiesta loved to do this.
I agree that sliding,power sliding, @ss out hooliganism etc, is what people commonly call drifting. I call it hangin the ass out...
Drifting (derived from 4 wheel drift I guess) is where you tank it into a corner and use the inertia plus lateral G to turn you in and as grip is failing, dial in a little throttle. Steering straight or thereabouts. I've done this a few times in my 318is recently. The M3 running gear and 4.1 LSD have made it ver neutral and agile. The completely foobarred tyres mean I can do it at low speeds in the wet so no brown pants! (just a bit yellowey).Incidently I found it easier in my 205 1.9 and MK2 golf 2ltr 16v. Little flick of the car, lift-off oversteer then bags of throttle with the wheel straight and front wheels spinning. Could DESTROY other quite quick cars on Coventry's A444 and ring road. Ahem, I didn't say that!


Jai Stanley

[jonbuoy]

But how can a slipping wheel have drive ?

A slipping wheel is spinning thus causing to drift accross a surface

[astondg]

Now imagine the same scenario but when the driver speeds up, the rear tyres go beyond their ultimate grip and deviate from the smaller circle. When the driver corrects this by turning the wheels in the direction of the slide, the course the front wheels take also deviates from the original, intended, circle. Thus over steer is understeer.

I don't agree with that. Most of the time if the back starts to slide then the front wheels will take a path around a smaller circle and eventually end in something like a "donut" or whatever they call them if it isn't corrected which is the opposite of understeer that created a bigger circle.

If it is corrected properly the front wheels will not deviate from the original circle. The best example I can think of to show you right now is when Jason Plato powerslides around in concentric circles in the first episode of the last Fifth Gear series. He has the back out and opposite lock on but he still follows the same circle he would if he was driving around on the limits of grip. That isn't the best example but is the only one I can think of right now.

Incidently I found it easier in my 205 1.9 and MK2 golf 2ltr 16v. Little flick of the car, lift-off oversteer then bags of throttle with the wheel straight and front wheels spinning. Could DESTROY other quite quick cars on Coventry's A444 and ring road. Ahem, I didn't say that!

AWD and FWD are easier to 4 wheel drift than a RWD, especially ones that lift off oversteer well. Once they get sideways you often don't have to correct it, getting back on the power pulls it straight again or holds the slide (depending how much you use and how you apply it).

Aston

[jaistanley]

I dont agree that the car will take a tighter circle. The actual path the car takes is a line drawn by the path of the centre of gravity of the vehicle.

In the situation you desribe the centre of gravity of the vehicle (say the dead centre of the cabin for example) is actually taking a larger radius circle. Trust me.. Get out a matchbox car and drive it round a CD and try it... Keep th front wheels on the circle and step the back out. What happens to the line drawn under the centre of the car?

To do doughnuts you would have to first steer into the centre of the circle first or your rear end will go past you (with the wheel held at the same position as the previous steady state) and your centre of gravity follow the larger circle till all of your inertia in theat direction is used and the car regains traction in a different direction.

I had to get my head round this as part ofmy degree a while back.

Our lecture notes were co-written by the head designer at prodrive and our vehicle dynamics lecturer. They are being published some time soon, he was working on that more than teaching us!

[bigkev]

its all about the friction coefficient when the car goes round a corner the weght is transferred to the opposite side if excessive this will overcome the tyres friction coefficient and the car will slew sideways but as the tyres are also rotating farward there is another friction coeficiency if the slew is greater than the drive you are sliding if the drive is greater than the slew you are drifting thats why its very dificult to drift a FWD because these two eficiencies are seperated
for example if you enter a right hander and the arse steps out and you keep the power on and the drive C/eff is just greater than the slew C/eff you will travel more in the drive direction than in the slew direction IE drifting
its easy

[astondg]

I dont agree that the car will take a tighter circle. The actual path the car takes is a line drawn by the path of the centre of gravity of the vehicle.

In the situation you desribe the centre of gravity of the vehicle (say the dead centre of the cabin for example) is actually taking a larger radius circle. Trust me.. Get out a matchbox car and drive it round a CD and try it... Keep th front wheels on the circle and step the back out. What happens to the line drawn under the centre of the car?

But if the back steps out the front wheels will not follow the same circle around the CD, they will go tighter, trust me . Maybe if you correct the slide the wheels will follow the same path and back of the car will follow a wider circle BUT we are talking about pure understeer and pure oversteer NOT corrected oversteer. You said oversteer = understeer and I say that is wrong, understeer != oversteer.

Here is a quote from another site that might be easier to understand than me:

If the rear tyres approach their traction limit more rapidly than the front, then the effect is for the rear of the car to steer a wider path than the front wheels. This rotates the car more than the driver intended and, if nothing is done, leads to the car turning a smaller radius corner. When this occurs the car is said to oversteer.

If the front tyre approach the traction limit more rapidly, the effect is that the front of the car takes a wider radius curve than the driver intended. The car is said to understeer.

Following you CD example though if you hold the back out (oversteer) and drive it around the CD the front wheels still follow a very similar path and the car continues around the CD (the same radius corner as before) which is what would happen if you corrected the oversteer and used some throttle control (a "drift") BUT if you push the front wide the front wheels no longer travel the same path and the car travels around a larger radius corner. With mild understeer and oversteer the mid point of the car might be in a similar position in both cases but they are following different radius corners and if you go to extremes the understeer will push it into a very large radius corner and the mid position of the car will no longer be the same for oversteer and understeer,

Also the centre of gravity is on the vertical plane (somewhere from the ground to the top of the of the car), it has no position along the length or width of the car while the car is sitting flat on the ground as far as I am aware because that is the way gravity acts. Anyway even if it does it depends on the front to rear weight distribution and in heavy front cars it might be a lot closer to the front rather than in the middle of the car.

To do doughnuts you would have to first steer into the centre of the circle first or your rear end will go past you (with the wheel held at the same position as the previous steady state) and your centre of gravity follow the larger circle till all of your inertia in theat direction is used and the car regains traction in a different direction.

I see this happen a lot at autocross on the dirt, if the car starts to oversteer and isn't corrected or isn't corrected enough it will definately end in a doughnut (or semi doghnut depending on how much speed it was carrying, surface grip, power, etc. but it at least begins to). The point is they turn a much tighter circle than before.

I have just done this in LFS (which isn't completely accurate but should be good enough for this discussion) and by driving around in a circle and then going wot and holding the steering at the same angle the whole time (the one I used to drive around in circles) I do eventually end up in a doughnut.

Aston

[Geoff]

Cant someone just post a vid of Tiff or someone 4 wheel drifting? Apologies if this has already been done.

[orangecurry]

easiest thing to do (and forget the maths at the same time) is just rent a DVD of one of the greatest films you've probably never seen

Grand Prix - 1966

http://www.imdb.com/title/tt0060472/

they had footage from real races, and got real racing drivers to do footage for them
Grahame Hill appears (unnamed) as a driver IIRC

of particular note is the best Monaco Grand Prix that never happened

[astondg]

Definately see that movie if you haven't already. I bought it on video but I haven't seen it around much so it might be a bit hard to find but definately worth it.

Aston

[TommyC]

God i hate car dynamics......Im doing my own head in......

I would need to see a video of "4 wheel Drifting" to grasp the concept.

My mind is to logical....

Car mass rotaintg around axis, rear wheels providing forward momentum, Causing the rotaion of the mass about its axis to become an arc ?

Here's an Audi Quattro E1 Group B rally car, 550 bhp, 4WD, and some tit at the wheel.

I believe this is 4wheel drifting, but because of the grip he has, he's trying to scandinavian filck the car around to start the drift.

http://videos.streetfire.net/Player.asp ... 2B36A57673

If you were to see a slow mo vid of these cars when they are on gravel you'd appreciate how a 4wheel drift still turns through an arc even though it's a very loose surface the cars are driving on!!! You can also see the wheels rotating faster then the car is actually travelling!!!

[orangecurry]

why on earth did you say 'some tit at the wheel'?

it looks like he is learning well and having fun?!?

but this isn't really what I was talking about - 4wd powersliding isn't difficult - but as you say it does show some of the maths/dynamics