Brake bias - default setup way off?

dave.andreason

New member
I
I've had to adjust the default brake bias on cars by crazy amounts... like 7-12 clicks to the rear on most cars. I switches to the vet from the Porsche and was wtf is with the default bias? Just me?
 
Could be. I run about 10 clicks forward on most default setups. With no ABS or stab control I lock the rears and spin on corner entry if I have it too far to the rear.
 
I'm not a setup guru but I wouldn't say they're way off, maybe a bit too much rearwards. I've moved bias 3-4 clicks forward for LMP2 and for hypercars (499P) only couple of clicks forward plus fine tuning with migration. And naturally brakes needs to be warm to work well.
 
I haven't raced the Hypers yet, but in the Aston and in the LMP2 I've shifted the brake bias back if anything, from the default setup. I tend towards front lockups when turning in, haven't had much (perhaps any) spinning due to the rears locking.
 
This is exactly why we are so slow, compared to the best. And I repeat "we are".
Trail breaking is in great deception. Not quite a deception, but a half-truth? It says you have to carry your braking into corners, but forgets to mention that this only works if your car is oversteering.
The car must rotate on its own, due to the sole effect of the brakes, with very little steering. If you bias the braking forward, you will be forced to rotate the steering wheel too much, but the car will not steer again, so you will still brake, until due to your low speed the front tires grip, turning your car into a spinning top on itself.
Do private stints of the same length as the race, in the same conditions as the race, without fighting, with a constant pace. Use the tire HUD and monitor consumption. You will find that with standard bias the tire that wears out first is the outside front. This will make you go straighter and straighter when cornering, forcing you to brake more and rotate the steering wheel too much, until sooner or later, about halfway through the stint, you will spin. But paradoxically this happens because you are understeering too much and have to force the rotation.
A few clicks back before starting the stint, so that the front and rear tires have the same degradation, and force yourself to turn the steering wheel less and stay on the track. You will see that the times will also improve.
 
I agree, and wasn't able to get any rotation with the default bias setting. Instead of having the rear rotate in trail breaking the front was breaking loose. Everyone will have their own perfect balance, I was just surprised how much I had to change it to get mine. I doubt that the green sim racers will find that sweet spot.
 
Hang on a moment.
How are you guys adjusting the brake bias. When I use my default wheel toggle it just flickers. I was assuming brake bias wasn’t finished yet??
Most cars need a little forward %
 
No problems with onboard bias/migration adjustments here either.

I must say I've become a fan of this brake by wire technology. It's quite interesting to fiddle with the migration system.
 
Pas tout à fait une tromperie, mais une demi-vérité ? Il indique que vous devez freiner dans les virages, mais oublier de préciser que cela ne fonctionne que si votre voiture survire.
La voiture doit tourner toute seule, sous le seul effet des freins, avec très peu de direction. Si vous freinez vers l'avant, vous serez obligé de trop tourner le volant, mais la voiture ne dirigera plus
 
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Pour moi il ya du vrai mais c'est plus subtile que ça.
Si vous réglez les freins en survirage, façon Karting, il vous sera impossible de freiner au maximum sinon le survirage risque de se déclencher avant le virage. Vous allez le gérer quelques tours puis vous mettre au tas. Par ailleurs ça va avoir comme effet d'asseoir l'arrière plutôt que de faire plonger l'avant, or c'est l'avant qui nous sert à garder le contrôle de la voiture et de la trajectoire. Plus vous mettez du survirage plus vous réduisez le freinage à l'avant et en perdez également à l'arrière qui est en glisse, les distances de freinage vont obligatoirement s'allonger.
Donc de mon point de vu le freinage doit être neutre.
Le déclanchement du virage est géré par 2 facteurs :
- le pilotage, en effectuant le freinage dégressif avec le petit coup de volant et de gaz qui vont bien pour provoquer ou non le survirage.
- le réglage du différentiel qui s'occupe justement de la répartition aux roues extérieures du freinage et de l'accélération en fonction de l'angle du virage.

Ce que tu décrit GoooAlex est plus dû au fait que le dégressif n'est pas géré correctement. Plus la voiture ralentit et plus le frein est puissant. Si la pression du frein est constante, les roues vont commencer à glisser en fin de freinage, d'où la nécessiter de relâcher progressivement le frein, généralement jusqu'au point de corde, et ça a également l'avantage d'effectuer progressivement un transfert de masse vers l'arrière et donc gérer plus facilement le grip en courbe.

Personnellement, je règle la voiture en freinant en ligne droite, ou légèrement en courbe jusqu'à la limite d'adhérence, puis dès qu'un pneu glisse je tourne légèrement. Si elle va tout droit, je mets des clics vers l'arrière, si elle survire je mets des clics vers l'avant. Lorsque les 4 roues glissent en même temps le réglage est ok pour un freinage optimal. Je le fais systématiquement à chaque sortie pour ajuster en fonction du grip.

Pour répondre au sujet du fil, oui, je trouve que la plupart des Bias par défaut sont beaucoup trop sur l'avant.

NB : attention sur les hybrides, suivant la puissance de recharge choisie, la récupération freine plus ou moins les roues alimentées par l'électrique, cela modifie fortement l'équilibre de freinage donc pensez à bien vérifier quelles roues sont alimentées électriquement et à ajuster le biais en conséquence. :cool:

For me there is truth but it is more subtle than that.
If you set the brakes to oversteer, Karting style, it will be impossible for you to brake as much as possible otherwise the oversteer may be triggered before the turn. You'll handle it for a few rounds then get down to business. Furthermore, it will have the effect of sitting the rear rather than making the front dive, but it is the front which we use to keep control of the car and the trajectory. The more you oversteer, the more you reduce the braking at the front and also lose some at the rear which is sliding, the braking distances will necessarily lengthen.
So from my point of view the braking must be neutral.
The triggering of the turn is managed by 2 factors:
- steering, by carrying out degressive braking with the slight stroke of the steering wheel and gas which go well to cause or not oversteer.
- the adjustment of the differential which takes care of the distribution to the outer wheels of braking and acceleration depending on the angle of the turn.

What you describe GoooAlex is more due to the fact that the degressive is not managed correctly. The more the car slows down, the more powerful the brake. If the brake pressure is constant, the wheels will start to slip at the end of braking, hence the need to gradually release the brake, generally up to the apex point, and this also has the advantage of gradually effecting a mass transfer to the rear and therefore more easily manage grip in curves.

Personally, I adjust the car by braking in a straight line, or slightly in a curve until the limit of grip, then as soon as a tire slips I turn slightly. If it goes straight, I put clicks backwards, if it oversteers I put clicks forwards. When all 4 wheels slide at the same time the adjustment is ok for optimal braking. I do this systematically on each outing to adjust according to the grip.

To answer the topic of the thread, yes, I find that most default Bias are way too forward.

NB: be careful on hybrids, depending on the charging power chosen, recuperation brakes the electrically powered wheels more or less, this significantly modifies the braking balance so remember to check which wheels are electrically powered and to adjust the bias accordingly.
 
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In English please. (I translated this one because I was particularly interested in the content) but I don't have the time (nor the inclination) to translate all posts that aren't in English.
 
As a novice with this kind of stuff, I just drove with whatever the default bias was, but once I had taken SC and ABS off, I found the cars much more difficult to control. I went forward with the bias and that seemed to give me more control and I was no longer getting snap oversteer part way through slow corners. Then I realised that I was just getting slower and slower as I was struggling to make the turn-in. So in the last few days I've pushed the bias back again so that it is now pretty much 50:50 and I certainly find it easier to drive, although on cold tyres at the start of the race I find myself at great risk of spinning like a top in the very slow corners. I've done half a dozen GTE races at Fuji and in three of them I have spun on L1 either at the chicane or at the hard left uphill penultimate corner (which I've always struggled with). Once my tyres have warmed up it's a lot easier. Any more hints and tips would be appreciated.
 
As a novice with this kind of stuff, I just drove with whatever the default bias was, but once I had taken SC and ABS off, I found the cars much more difficult to control. I went forward with the bias and that seemed to give me more control and I was no longer getting snap oversteer part way through slow corners. Then I realized that I was just getting slower and slower as I was struggling to make the turn-in. So in the last few days I've pushed the bias back again so that it is now pretty much 50:50 and I certainly find it easier to drive, although on cold tires at the start of the race I find myself at great risk of spinning like a top in the very slow corners. I've done half a dozen GTE races at Fuji and in three of them I have spun on L1 either at the chicane or at the hard left uphill penultimate corner (which I've always struggled with). Once my tires have warmed up it's a lot easier. Any more hints and tips would be appreciated.
What sometimes helps is a little extra toe in, it will make steering feel a little heavier but a bit more stable under braking. May help you.
 
Trouble is I pretty much only race online with the fixed setups in the beginner races (as the race lengths suit me). I don't believe things like toe-in are adjustable in those races.
 
As a novice with this kind of stuff, I just drove with whatever the default bias was, but once I had taken SC and ABS off, I found the cars much more difficult to control. I went forward with the bias and that seemed to give me more control and I was no longer getting snap oversteer part way through slow corners. Then I realised that I was just getting slower and slower as I was struggling to make the turn-in. So in the last few days I've pushed the bias back again so that it is now pretty much 50:50 and I certainly find it easier to drive, although on cold tyres at the start of the race I find myself at great risk of spinning like a top in the very slow corners. I've done half a dozen GTE races at Fuji and in three of them I have spun on L1 either at the chicane or at the hard left uphill penultimate corner (which I've always struggled with). Once my tyres have warmed up it's a lot easier. Any more hints and tips would be appreciated.
Start with 52 and go down to 51 after a couple of laps, and then move to 50 after another 2. You drive better because you wear the front tire less, shift the bias as the tire wears out.
 
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Cars have very different approaches for BB, some are close to ideal, and others are very rear-biased causing easy rear locking at hard braking.

To be fair, in general, I think tires lack a bit of grip in general (with warmed tires already), look how Kobayashi can keep the brake at 100% at the end of straights fairly, doesn't have to trail brake, and easily takes Eau-Rouge with Toyota.

Another feeling that bothers me is the generic weight balance disturbing that all cars suffer in up-shifting, especially the GTE's - it doesn't matter if it is a Porsche or an Aston, feels the same weird way - and is there for all of them.


 
... look how Kobayashi can keep the brake at 100% at the end of straights fairly, doesn't have to trail brake, and easily takes Eau-Rouge with Toyota.
Real cars don't have 100% braking. What you're seeing is brake pressure calibrated to a certain force for 100% - so anything higher isn't visible.
 
I apologize for the obvious thing I'm about to say, but perhaps it needs to be said so that everyone understands. The brakes act on the tires, but it is the tires that slow the car. When adjusting the Bias you must keep in mind the grip level of the tires, and also the characteristics of the circuit. The best drivers adjust the Bias during the lap, before the corners, depending on the corner they do.
When you leave the pits or start the race, the tires are new, and you have the same level of grip, front, rear, right and left.
As you go around the track you will wear the front or rear tires more, the left or right side. Therefore the setup also serves to keep the car in balance with tire wear.
For example, if you wear the front tires more than the rear, when you brake you will require a level of grip from the front tires that they no longer have. While at the beginning the braking was balanced, now you are braking too much with the front and not enough with the rear. So you will wear the front tires more and more, and the car will be more and more understeered when entering corners. And the more poorly you brake, the more you unbalance the car for subsequent corners.
On the contrary, if the set-up wears the rear tires more, braking will require a higher level of rear grip than the tires can provide, and the car will be increasingly nervous at the rear.
Accidents also change the grip level. Many people think that a little rubbing between cars is normal, but this is actually not the case. In reality the pilots fight very close to each other but do not touch each other. Every small bump changes the geometry of the suspension and causes the tires to fail. Each exit from the track heats up and damages the tires unevenly, and subsequently when you brake the behavior will be different, as will the wear of the tyres.
A tire lockup on the first lap can compromise the behavior of the car for the entire race.
Fuel consumption changes the weight and ride of the car while driving.
How many times have you reached a driver at the end of the race who can no longer stay on the track? How many times has this happened to you? They ruined the tires in just 20 minutes, due to poor handling, accidents or bad driving.
It seems clear that all the controls that can be modified from the car's cockpit are there on purpose to compensate for the car's behavior while driving. And they must be used for that purpose.
 
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