Brake Bias Adjustment

[dafeller]

I apologize in advance for not being totally aware of every possible technical and operational development in F1, but I was wondering about brake bias adjustment in the current F! form. Such adjustment has been available in racing cars for a long time, but I understood from the early incarnations that the adjustment was useful to make up for wear issues and weight shifts over the course of a race. I think I first recall reading about it in the 917.

The talk about Ferd 'Mira mama, sin manos!' Alonzo's use of his hand to adjust brake bias so often that he was often left driving without hands on the wheel each lap (at least I took the inference that he was doing it as often as per lap, or even per corner in some instances) really surprised me.

Enlighten me, oh PH gurus. I would think that brakes would be one area where technology, via computers or otherwise, was more automatically perfected in the ongoing car. Apparently not. Is it really possible that bias must/should/is best adjusted for different corners on each lap?

[mchammer89]

I like it like that. If leave the automatic devices for road cars. This is racing, they should be able to make the most out of the car themselves, let them alter brake bias themselves. Hopefully we get back to manual transmissions as well soon enough.

[topless_mx5]

dafeller said:

The talk about Ferd 'Mira mama, sin manos!' Alonzo's use of his hand to adjust brake bias so often that he was often left driving without hands on the wheel each lap (at least I took the inference that he was doing it as often as per lap, or even per corner in some instances) really surprised me.

Alonso was driving with one hand because he was using the 'F-duct' on the straights, which is why him driving with one hand was the focus of attention.

[Jasandjules]

I can only surmise that the technology to do this is in some way banned, as I can't imagine it is not possible for them to program the car to adjust the brakes at each corner etc.. as needed - perhaps then with some form of manual over-ride in case of a banzai overtake or somesuch.

[flemke]

Automatic bias adjustment would be ABS, which has been banned since '93.

[GTP rpm]

flemke said:

Automatic bias adjustment would be ABS, which has been banned since '93.

Ahhh...I always wondered what ABS stood for...

[woof]

flemke said:

Automatic bias adjustment would be ABS, which has been banned since '93.

! anti-lock braking system you mean

What drivers are doing is adjusting the bias according the how much they might need in a particular corner. It seemed that they were winding more forward on the downhill sections and less on the uphill.

I'm sure it's more scientific that - maybe it is to save brakes etc and not use the fronts so much. Not sure I would remember to do it 3 or 4 times a lap whilst racing or defending hard.

[nsmith1180]

This is a good point, but wouldnt it be possible to make it an electronic adjustment on the wheel. I know that thats getting quite full now, but surely a busy wheel is better than driving without any hands like FA was doing when adjusting bias and using that criminally dangerous F-Duct system.

[woof]

just reading up on it

So they generally adjust to the front for long braking zones with little to no steering input. To maximise the front braking.

[mchammer89]

woof said:

Not sure I would remember to do it 3 or 4 times a lap whilst racing or defending hard.

Like most things I guess it would become second nature after a while.

[anonymous-user]

Brake bias requirements vary for each braking zone.

Modern F1 cars have quite complex mechanical systems with a quick change mechanism for bias change using a combination of valves to achieve the desired effect. Some of the details of the Ferrari system were given away by the FIA during the McLaren saga when they released the document on the various technical systems without properly blanking out the secret information held in the documents.

The Ferrari at the time used a double-rear master cylinder with a spring, which initially delayed rear braking, then increased it gradually, so a mechanically based but automatic system of bias change.

[flemke]

GTP rpm said:

flemke said:

Automatic bias adjustment would be ABS, which has been banned since '93.

Ahhh...I always wondered what ABS stood for...

I did not mean to suggest that the abbreviation "ABS" was derived from "automatic bias". It was just that much of what an ABS system does results in altering the bias (laterally, as well as longitudinally), so on that basis it's not permitted.

[flemke]

johnfelstead said:

The Ferrari at the time used a double-rear master cylinder with a spring, which initially delayed rear braking, then increased it gradually, so a mechanically based but automatic system of bias change.

So the system always shifted the bias to the back partway through each braking period?
Not that different from the spring application in the Ferrari's flexible floor that same year.

[anonymous-user]

It would make sense to do so as the aero generated grip drops off as speed reduces and the mechanicaly generated grip increases in relative terms, with the rear tyres having more surface area than the fronts, they are more capable of generating retardation under pure mechanical grip conditions (ie low downforce).

[flemke]

johnfelstead said:

It would make sense to do so as the aero generated grip drops off as speed reduces and the mechanicaly generated grip increases in relative terms, with the rear tyres having more surface area than the fronts, they are more capable of generating retardation under pure mechanical grip conditions (ie low downforce).

Yes, it's a neat idea (for the brake bias, not for the floor!).
I'm wondering if, also, it might have helped to get the car turned (as an alternative to shortening braking distance). For any given rate of deceleration, although you shift the brake bias, you've got essentially the same F-R weight distribution at any moment, so contact patch is the same. But if the front tyres are doing less of the overall braking, they've got more potential side force.

[mchammer89]

flemke said:

johnfelstead said:

It would make sense to do so as the aero generated grip drops off as speed reduces and the mechanicaly generated grip increases in relative terms, with the rear tyres having more surface area than the fronts, they are more capable of generating retardation under pure mechanical grip conditions (ie low downforce).

Yes, it's a neat idea (for the brake bias, not for the floor!).
I'm wondering if, also, it might have helped to get the car turned (as an alternative to shortening braking distance). For any given rate of deceleration, although you shift the brake bias, you've got essentially the same F-R weight distribution at any moment, so contact patch is the same. But if the front tyres are doing less of the overall braking, they've got more potential side force.

+1 It is a very intelligent idea, I do think that the assisting with turning that you mention would've been what they were going for. It's these sorts of innovations that I love about F1, all of the little aero additions just annoy me. They should be cars, not upside down jet fighters.

[davepoth]

As has been said above the brake balance is quite critical in F1 cars. The drivers are adjusting more this season due to the changes due to fuel load, but it has an important effect in braking zones. Going down into a tight corner from a straight (La Caixa at Barcelona) it makes sense to have the balance forwards to maximise the braking force. But for a curve like Campsa corner at Barcelona you'll want the balance a bit further back so that you have more front grip available to make the turn at a higher speed.

[mchammer89]

Probably not the right thread to discuss it, but seeing as the OP has been aswered I figured it wouldn't do much harm. I hold the opinion that the designers should be pushed more towards developing the mechanical side as opposed to the aerodynamic side of these cars. For better racing and more relevance to road cars. Seeing as they already have to conform to quite tight dimension regs, how would it work if they were given a standardised body to place on the chassis?

I mean they would still be free to develop everything aside from the part which bears little load (excluding aero load I mean) and it would solve many problems. The body could be designed to not be so dependant on aero grip reducing both the turbulance generated by a car and it's affect on the car following behind. Other problems such as the mirrors stuck at sily positions would also be eradicated. Can't see it happening, but to me it's a nice idea.

[dafeller]

johnfelstead said:

Brake bias requirements vary for each braking zone.

Modern F1 cars have quite complex mechanical systems with a quick change mechanism for bias change using a combination of valves to achieve the desired effect. Some of the details of the Ferrari system were given away by the FIA during the McLaren saga when they released the document on the various technical systems without properly blanking out the secret information held in the documents.

The Ferrari at the time used a double-rear master cylinder with a spring, which initially delayed rear braking, then increased it gradually, so a mechanically based but automatic system of bias change.

Thanks, that's very helpful.

[dafeller]

johnfelstead said:

Brake bias requirements vary for each braking zone.

Modern F1 cars have quite complex mechanical systems with a quick change mechanism for bias change using a combination of valves to achieve the desired effect. Some of the details of the Ferrari system were given away by the FIA during the McLaren saga when they released the document on the various technical systems without properly blanking out the secret information held in the documents.

The Ferrari at the time used a double-rear master cylinder with a spring, which initially delayed rear braking, then increased it gradually, so a mechanically based but automatic system of bias change.

Thanks, that's very helpful.