Maybe it is possible to explain in a few words the fine art of countersteering to bring the front into optimum slip?
Thought it might be a good idea to begin with some humor.
Or just start out from scratch and try to finish...
"Traction" is grip on the rear caused by throttle input which, when modulated, can be applied to steer the car by causing the car to rotate around its center of gravity, (CoG).
Traction causes oversteer when the rear is already swung out, (pour tourner à l’arrière), by lifting the throttle momentarily and allowing the diff to go into coast, maybe while tapping the brake just enough to set the car in comfortable stance for acceleration.
If the rear is not swung out, (nicht ausgeschwenkt), traction can easily cause more tendancy to understeer, while the car is pushed into track camber. In this case, turning the steering wheel when accelerating does not prevent the car from wanting to go off on the outside.
All GPL differentials, just like in the real world, cause power side understeer.
To compensate for the diff, many drivers often prefer, as they gain experience, to tune out diff-induced power side understeer as much as possible, so it is easier to steer the car, especially at speeds slower than typical of those involving any sort of high speed drift.
This is where the most interest in neutral steering comes from, because from there, at slower speeds, as the car accelerates, traction increases grip at the same time traction is steering the car into oversteer that carries the car around the turn.
Given a moment of neutral steering, as soon as traction is applied the car will be oversteering as the rear will seem to swing out behind the driver.
This is a very important moment.
The rear has to swing out and roll over far enough to load up the outside tire and twist the rear tire into optimum slip.
If not, there is grip to gain.
And if not, there is time, speed, and distance lost.
In the mid-to-late 60s, with big innovations in tire technology, optimum slip had advanced down to about 8 to 10 degrees of slip required to yield maximum grip before the tire begins to slide with no grip.
This is when they invented the square wheel, 15inDIA by 15inW, which proved there is a practical limit on tire tread width relative to diameter.
In the 50s optimum slip angle per tire was around 15degs. Beginning in the 70s optimum slip evolved rapidly to now an F1 car with hot track and tires is looking for 3deg or less of optimum slip.
As slip angles were reduced by advances in tire technology, over time steering wheel diameters, reflecting by radius the leverage required to twist a tire patch off its rim, got smaller and smaller.
Steering wheel shapes changed dramatically while their significance as suspension levers diminished and significance as system control panels increased.
A rule-of-thumb for Grand Prix Legends could be, (pick a reasonable number), say 8-degrees at optimum slip.
There have been reports by a pretty quick on-line driver of Replay Analyzer recording Papy 67s slip angles of nearly twice that, with the average being between 8 and 13, which suggests a whole lot of grip and loading is possible.
This means to get to optimum slip the car has to, (it will and does every time), twist and roll its way off and around its center, (static CoG), some number of degrees while the tire patches are skewed out of alignment with their rims, until they get twisted or not into optimum slip and maximum grip.
As soon as the rear hops out to 8degs or so of slipped-off its static center, due to traction and the diff, the front goes rotating off in the opposite direction, and the driver wrestles with oversteer, as the car seems to want to drop off track camber and dive off into the inside of the turn.
This is exactly what is supposed to happen except for one thing.
While the rear of the car seems to be swinging out searching for maximum load, optimum slip, etc, the front is taking the path of least resistance, and will never get anywhere near optimum slip if the driver does not turn the wheel to the outside, forcing the front tires into the track surface camber.
The front must be set with enough front roll to be steered into the track camber with sufficient leverage to twist the tire patch away from the rim and bring it close enough to the same slip angles as the rear...and vu-ah-la, high speed neutral steering.
(Neutral steering: when slip angles are equal or cancel out to zero and car maintains undiminished path of current intended trajectory with increasing throttle input).
Just guessing this might require a little more steering wheel input than 8degs, but not much?
Probably varies with steering ratio, wheel settings, grip level, track camber, speed, spring rate, tire temp?
The driver only has to effect an 8deg slip angle on the front. The rear is already going there.
This often requires very little leverage on the steering wheel.
When countersteering into track camber to increase front slip angles to match the rear slip angles, FFB is telling you exactly how much lateral force is being caused by setup, track camber, and by throttle.
If for example the steering wheel is turned 40degs to begin and hold a line, compensating for traction induced oversteer might find that FFB level of resistance in the wheel at somewhere around 32degs?
Ok, probably not 1:1, but concept of it is the point. There is a direct relationship between front slip angles and steering input.
Rear traction oversteer plus front countersteering understeer equals zero slip angle difference between front and rear.
Constant radius optimum slip turn across track camber = traction + steering input = (-8F) + (+8R) = 0, (or the other way around). If less than optimum slip, the trajectory is maintained by (<0) + (>0) = 0.
An observer would likely not, or likely might not. see the countersteering effort at all, as it is only felt by the driver in the FFB response and the motion that initiates implementation takes about or less than 4/5ths of a second, (according to sources in above posts).
Traction increases due to throttle are anticipated on the front in direct coordination by simultaneous steering input to balance the car on an accelerating trajectory.
This is how with direct control all four tires can be placed and held in optimum slip.
Throwing a car into a semi-controlled full lock powerslide is not the same as placing and holding a car in optimum slip.
The preferred slip angles are zero, because it means the car is going straight and covering the most distance in least time.
During a turn within a corner, the preferred slip angles are the minimum that carry the car through on the maximum radius line.
Less than optimum slip is better if it means higher speed through a corner.
If you don't need to, don't go there.
The point of taking a car to optimum slip is not to reduce the time and distance within the turn. It is to have more speed at exit, and most importantly, to in-effect lengthen, most of the time, or sometimes shorten, the distance of the next straight.
By making the next straight longer, another second or so at higher top speed can be achieved, which is when the most time anywhere on track is saved, and distance covered, before slowing for the next turn.
That is one way a tenth is gained and over several laps can yield a challenge for position.
Engineers for tire manufacturers tell race engineers and drivers the loads required to put their tires in optimum slip.
It is the driver's responsibility to know how to do that and their job to get it done.
Questions and guesses
All caveats apply
Reserving the right to edit
Apologies if this does not translate well
Please ask if any confusion
Probably will appreciate any correction and discussion
Edited by John Woods, Mar 20 2021 - 08:47 AM.