Drifting vs. Power-sliding

[hightower99]

Originally Posted by MrKipling

Grip is simply a measure of how much traction you have, not really a force in its own right.

Hence why we need to agree on how to use the word "grip" I didn't use the word grip as a force but to describe the time when a wheel is not slipping or sliding but still generating tractive forces.

Originally Posted by MrKipling

Which is caused by flex in the sidewalls when the grip of the tyre exceeds the possible turning moment. It doesn't mean that the tyre is slipping across the surface of the tarmac.

Yes I know a slip angle is when the direction of travel and the apparent direction of the wheel differ however there can be slipping and sliding and without.

Originally Posted by MrKipling

I guess you're refering to the 'snappiness' of F1 cars i.e. their tendancy to spin at the point they break traction? That's because of the set up trade-off between the width of the line between smokey tyres and a crash, and ultimate cornering speed. The narrower the line, the higher the cornering speed - F1 cars have no need to move around so, through very stiff suspension and so-on, that line can be atom-thin. The reliance on aerodynamic grip also has a huge impact: if the car is not moving straight into its direction of travel, none of the wings will be working and you'll lose enormous amounts of grip in a split second - spin-a-rama.

Yes like I said the tires are designed so that they are in grip mode right up to the limit of traction.

Originally Posted by MrKipling

That depends on the type of power delivery the engine provides relative to the grip level of the tyres (torque vs power for example), weight distribution, driveshaft wind-up, tyre type, weather conditions etc etc. If you try that chirping technique in a 911, you stand a good chance of wasting tenths to axle tramp.

By chirping I meant that the wheels where rotating faster than the velocity of the vehicle. To get the most traction out of any tire you need to go beyond grip mode (even in F1 but there it is such a fine line that you shouldn't try)

Originally Posted by MrKipling

On road tyres, yes.

On all tires... Even in F1 the limit of traction is just ever so slightly beyond the grip mode limit of the tire.

Originally Posted by MrKipling

Depends on the tyre, the car and the purpose, if by 'maximum traction' you mean 'going as fast as you can go'

By "Maximum traction" I mean maximum traction... traction being the ability of the tire to restrain lateral acceleration and produce straight line acceleration and deceleration. You make the most when the tires are slipping ever so slightly and on some tires smoke is produced.

Originally Posted by MrKipling

Rally cars don't really oversteer though, you only ever see the back trying to overtake the front during hairpins. The trick to rally driving is balancing the throttle that's taking you forward via the four wheels against the what has always been known (long before D1) as a four-wheel drift, to create an arc from entry to apex to exit. In rallying all four wheels are moving across the surface towards the outside of the corner - oversteer is when only the back of the car has those tendencies.

In any sharp corner in a rally, every car that makes it through will have been in oversteer at some point during the corner. By the way, when the centerline of the car and the line of travel are not the same and when the cars centerline is pointed so that the front is closer to the inside then the back then the car is in oversteer.

[MrKipling]

Originally Posted by hightower99

Yes like I said the tires are designed so that they are in grip mode right up to the limit of traction.

No, like I said, it's the set-up - not the tyres - that makes F1 cars handle the way they do. The tyres are designed for the cars, but the set-up creates the handling characteristics.

Look, it is physically impossible (as in, by the laws of physics) to gain maximum accelerative force from a tyre that is beyond its limit of grip. If you're making smoke or sound, you're wasting energy that would be much better spent tranfering forces to the road - be it braking, accelerating or steering.

The only reason people seem to think that the quickest way for a car to move is if the tyres are chriping is because it is the only way to tell when you're that close to the limit of traction, and in a 'low' powered car it gives you more options for line adjustment.

Oh and in case you were wondering, rally cars are set up to understeer,

[hightower99]

Originally Posted by MrKipling

No, like I said, it's the set-up - not the tyres - that makes F1 cars handle the way they do. The tyres are designed for the cars, but the set-up creates the handling characteristics.

So tires aren't an important part of a car's setup?

Originally Posted by MrKipling

Look, it is physically impossible (as in, by the laws of physics) to gain maximum accelerative force from a tyre that is beyond its limit of grip. If you're making smoke or sound, you're wasting energy that would be much better spent tranfering forces to the road - be it braking, accelerating or steering.

Well actually at the highest limit of traction friction is increased because bonds between the molecules of rubber in the tyre break...

Originally Posted by MrKipling

The only reason people seem to think that the quickest way for a car to move is if the tyres are chriping is because it is the only way to tell when you're that close to the limit of traction, and in a 'low' powered car it gives you more options for line adjustment.

I disagree. To get the most traction out of the tires they have to break the bonds. Just look at any fast drag car. the winners are almost always the guys who have only a thin puff of light blue smoke from their tires when they launch, not the guys who take off with no slip at all.

Originally Posted by MrKipling

Oh and in case you were wondering, rally cars are set up to understeer,

Depends on the car and stage but yes sometimes rally cars are set for understeer. Why? because on gravel roads if you set the car up for oversteer you would not be able to control the car.

[Alastor]

Originally Posted by hightower99

So tires aren't an important part of a car's setup?

Well actually at the highest limit of traction friction is increased because bonds between the molecules of rubber in the tyre break...

I disagree. To get the most traction out of the tires they have to break the bonds. Just look at any fast drag car. the winners are almost always the guys who have only a thin puff of light blue smoke from their tires when they launch, not the guys who take off with no slip at all.

I do not see how “breaking” rubber bonds helps improve traction.

When corning for example, at a slip angle that produces maximum lateral force some of the contact patch will be sliding with respect to the ground. I can see how this might produce smoke or noise at peak performance levels.

But if the bond between the tire and the ground breaks, then force can nolonger be transmitted across the tire-ground link.

[hightower99]

Originally Posted by Alastor

I do not see how “breaking” rubber bonds helps improve traction.

When corning for example, at a slip angle that produces maximum lateral force some of the contact patch will be sliding with respect to the ground. I can see how this might produce smoke or noise at peak performance levels.

But if the bond between the tire and the ground breaks, then force can nolonger be transmitted across the tire-ground link.

I didn't say the contact between tire and ground breaks I said the bond between the molecules in the tire break.

Basically for total traction when a molecule of rubber in the tire comes into contact with the ground then to transfer the most energy it most break from the tire and stay with the ground, but not until it is at the end of the contact patch...

[Alastor]

Originally Posted by hightower99

I didn't say the contact between tire and ground breaks I said the bond between the molecules in the tire break.

Basically for total traction when a molecule of rubber in the tire comes into contact with the ground then to transfer the most energy it most break from the tire and stay with the ground, but not until it is at the end of the contact patch...

You are saying that by that by breaking the bonds in the tire the maximum about energy is transferred through the tire.

If I am understanding that correctly then it refers to the friction component of traction not the total traction. It seems to me that this would only be useful for the thin layer of rubber interacting with the ground. Other wise excessive bonding breaking would generate an excessive amount heat.

[kigango123]

Originally Posted by hightower99

To be able to get this thing finished everyone should agree to the meaning of certain terms.

Grip: When a wheel is not slipping or sliding at all (no smoke) it has grip, although during cornering a slip-angle may be present (ie the wheel appears to be pointing in a different direction then it is traveling but there is still no smoke or screeching). A tire will run out of grip long before it runs out of traction. F1 however is special because the tires are designed so that the grip of the tires continues right up to the limit of traction.

Traction: Used to describe the limits of force transmission between the tire and the ground. For example most tires produce the most traction for acceleration when they are slipping slightly, producing very little smoke (chirping). Also during cornering the very limit of traction will be when the tire is slightly slipping. When you pass the limit of traction any additional force is wasted and the current force allowed is not the same as when at the limit (alot less so normally).

D1 championship slides the rear tires to produce their drift, while the front tires grip and are well within their traction limits.

Real drifting that allows you to drive the fastest is about maintaining all 4 tires at their limit of traction (hence alittle slipping and little smoke). The mastery is combining cornering and acceleration and deceleration forces without passing the limit of traction, the closer you get the faster you are.

Now in my mind power sliding is using the force generated by the engine to exceed the tractive limits of the back tires so that the car exhibits oversteer, which needs to be maintained and controled by counter steering and throttle control.

D1 does this but takes it to another level where they maintain the powerslide through a series of corners. Hence D1 is actually glorified extreme powersliding, not drifting. However rally racing where cars take corners with oversteer is not powersliding, it is force vectoring. Rally racers need to get the car into oversteer because on loose ground (which allows low levels of grip and traction) you need to corner by using the radial force retaining abilities of the tires instead of the axial.

i agree with sir High tower.

ever watch those free dvds about early drifting, i mean early jgtc racing in japan. you find that they were actually drifting to find the fastest route through a corner. in todays d1 they purposly e-brake, breaking traction, they just use the radial force on the rear tire, to control the car.

real drifting as in the first definition can be done in rear wheel ,forward wheel drive and all wheel drive easily.

[MrKipling]

Sorry, but hightower is talking rubbish... F1 cars are the perfect example of how to go round a corner quickly, and you'll never see them 'making puffs of smoke' unless they cocked up.

Of course tyres are important for handling, but all they do is transfer the forces (influenced by set-up) to the tarmac.

Because, unlike some people on this forum, I'm not arrogant enough to assume that I know everything; I checked this out with a bunch of people I know who do know (rally driver, circuit instructor, engineer) and they seemed to agree with what I was trying to say... mainly because, in this case, I am right.

Kigango, no one is likely to take you seriously when you have a signature like that.

This will be my last post on this thread I think... I'm tired of arguing with idiots - I'm beginning to understand why Matra left. What a load of b*llocks.

[McReis]

Originally Posted by hightower99

Real drifting that allows you to drive the fastest is about maintaining all 4 tires at their limit of traction.

Sure, but that is only when aerodinamics ans physics don't allow you to do it in a better and cleaner way like, say, in a F1. No need for 4 wheel drifts there.

Originally Posted by MrKipling

I'm tired of arguing with idiots - I'm beginning to understand why Matra left. What a load of b*llocks.

Yes, you got it right: he left because he also couldn't take a deep breath and understand that there will always be stubborn members and that calling them idiots won't help either them or him. Calm down.