59 replies to this topic

[JoshKnight]

Hello i was wondering wheather you guys could help. I was talking to a couple of my friends and we got talking about Brake Bias. One thing led to another and we was wondering which was the 1st F1 team and which year did they use a Brake Bias Adjuster in the car that the driver could change during the race. You see the driver do this several times during a race now.



Thanks for your help

[JoshKnight]

Nobody knows then?

[D-Type]

Josh, although the regular posters on here know a lot about racing - car and driver histories etc, they aren't generally that hot on the technical minutae. The mechanics and ex-mechanics who know about such things don't appear to be that interested in the history of racing and don't post here often.
Try posting the same question on the Technical Forum, but say you've asked here and drawn a blank.

[Bauble]

Josh,
It was probably first used in the late 1800's, by Mario Borgazetti on his self built MB special. The device would have been operated by a piece of string attached to the rear brake shoes, which were made of leather by the way, and caused the front of the car to lift slightly into the air. This had the double advantage of improving air flow under the vehicle giving an early ground effect as well as causing a 'castor action' which allowed greater cornering speeds. I am fairly sure that both Colin Chapman and Adrian Newey drew influence form the design.

The formula for the bias v lift is simply 'pi x 0.5682 squared + the sum of the diameter of the offside front and rear side near wheels. Minus tyres of course.

Hope this helps.

bauble.

[RS2000]

Nobody knows then?

You need to give it at least 24 hours! Not everyone looks in here every day.

I have no idea for F1. Probably the rear engined period. Maybe as late as the 1.5 litre F1?
In rallying, cockpit adjustable brake bias is not proven to be a "period" mod in the pre-1968 UK historic categories so is not permitted. Brake bias/twin master cylinders are allowed but mainly because the parts are readily available and some original type single master cylinders are not. "Driver adjustable when seated" is not allowed. It may be that works Escorts in late 68 or 69 were first to use it, so same would apply to touring car racing.
The works rally Minis, for example, that weren't known for missing a trick, did not use it, despite the standard rear limiting valve being readily-adaptable to being moved inside the car and fitted with an adjuster. They fitted different pressure springs in the limiter but it was not driver-adjustable.

To this day, "driver adjustable when seated" brake bias is not allowed on any category of car in UK Hillclimbs and Sprints. The MSC/MSA have persistently declined to explain why, despite it being almost universal in racing and rallying now.

Edited by RS2000, 12 September 2011 - 16:09.

[David Shaw]

TNF is a great resource on which I could spend a large part of my day. Unfortunately, impatience is not likely to make a TNFer realise that they had better get a move on and answer your question for you, rather they may decide to pass over it and look at another thread on which they could provide input.

PS. Bauble, that formula is known to be accurate only when one knows how long is a piece of string.

Edited by David Shaw, 12 September 2011 - 16:24.

[Allan Lupton]

Perhaps if we extend the field to include any chassis-design parameter that can be adjusted by the driver we can point out that Connaught used a driver-adjustable roll bar on the rear at Monza in 1953. I believe that only one car (AL10, Salvadori) was so fitted, and the idea was not carried forward to the B type for Formula 1 in 1954.

ETA but see post no. 40 for correction and amplification.

Edited by Allan Lupton, 13 September 2011 - 17:34.

[arttidesco]

IIRC and I often don't, first time I heard of these devices was around the time of the Lotus 78 and Lotus 79 which would be around 1977/78, could Mario Andretti have been responsible for importing the idea from the USAC Champ Cars ?

I believe Ronnie Peterson was not a particular fan of these devices when he was driving for Lotus in 1978.

I am reasonably sure that Nelson PK was the first to use this idea in his Ralt RT1 Formula 3 car in 1978, why I remember this I do not know, I guess that is the way 50 year old memory works.

[cheapracer]

Ya was wondren' was ya's?

Hard to say but with the massive fuel weight in the rear and skinny tyres of a 1937 Benz GP car it would come as a surprise if they didn't have something to compensate during the race - that's a logic based answer but Leif Snellman would know I reckon ..

http://www.kolumbus.fi/leif.snellman/

http://forums.autosp...p?showuser=3422

[Roger Clark]

IIRC and I often don't, first time I heard of these devices was around the time of the Lotus 78 and Lotus 79 which would be around 1977/78, could Mario Andretti have been responsible for importing the idea from the USAC Champ Cars ?

I believe Ronnie Peterson was not a particular fan of these devices when he was driving for Lotus in 1978.

I am reasonably sure that Nelson PK was the first to use this idea in his Ralt RT1 Formula 3 car in 1978, why I remember this I do not know, I guess that is the way 50 year old memory works.

I dont recall those Lotuses using adjustable brake bias. They did use driver adjustable rear anti role bars and this was an idea introduced by Andretti.

[arttidesco]

I dont recall those Lotuses using adjustable brake bias. They did use driver adjustable rear anti role bars and this was an idea introduced by Andretti.

I was sure Andretti was responsible for introducing a knob to fiddle with into F1, thanks for correcting me on which one Roger

Does this mean Nelson PK was also playing with his anti roll bar and not his brakes in the Ralt RT1 in 1978 ?

[Bauble]

PS. Bauble, that formula is known to be accurate only when one knows how long is a piece of string.
[/quote]

Ah! Now that question has troubled mankind since time immemorial, even Iron Stein failed to crack the equation. The main problem is that while we all know that the piece of string has two ends, nobody has yet worked out the distance from one to 'tuther, and indeed if the distance varies according from which end you start your measurement.
I am of the opinion that the diameter of the string has no bearing on the eventual answer, but have no scientific basis for this believe. A well known US University tried to find the answer by cutting the string in half, measuring the two lengths and then adding the two together, however, this just multiplied the problem as they then had two pieces of string with no means of determining the length of either of them! Well it was a US establishment of 'learning'.

I suspect that the brake bias adjustment conundrum will never be unravelled until such time as the string situation is resolved.

Should any members of this forum find the science displayed here beyond their comprehension................. maybe they should consider the possibility they are just thick.

[Roger Clark]

Ya was wondren' was ya's?

Hard to say but with the massive fuel weight in the rear and skinny tyres of a 1937 Benz GP car it would come as a surprise if they didn't have something to compensate during the race - that's a logic based answer but Leif Snellman would know I reckon ..

http://www.kolumbus.fi/leif.snellman/

http://forums.autosp...p?showuser=3422

I'm not aware of any such device on the pre-war cars. They did modify the W196 during 1955 to allow the driver to alter rear wheel camber angle as fuel level reduced. The fact that this was a mid-season update suggests that it hadn't been used on the pre-war cars.

[Bloggsworth]

I can remember in the '60s Bob Curl showing me his bias pedal, designed so that the harder one pressed the pedal the more the bias moved towards the front, so twin cylinders for seperate F & B brakes were around then. I can't remember if it was his response to a driver adjustable system - I'll ask him.

[Bloggsworth]

PS. Bauble, that formula is known to be accurate only when one knows how long is a piece of string.


Ah! Now that question has troubled mankind since time immemorial, even Iron Stein failed to crack the equation. The main problem is that while we all know that the piece of string has two ends, nobody has yet worked out the distance from one to 'tuther, and indeed if the distance varies according from which end you start your measurement.
I am of the opinion that the diameter of the string has no bearing on the eventual answer, but have no scientific basis for this believe. A well known US University tried to find the answer by cutting the string in half, measuring the two lengths and then adding the two together, however, this just multiplied the problem as they then had two pieces of string with no means of determining the length of either of them! Well it was a US establishment of 'learning'.

I suspect that the brake bias adjustment conundrum will never be unravelled until such time as the string situation is resolved.

Should any members of this forum find the science displayed here beyond their comprehension................. maybe they should consider the possibility they are just thick.

I think you may be wrong, the diameter of the string will surely affect the degree of available stretch and therefore have a concomitant effect. The best way to measure a piece of string is to purchase a length of tarred rope, knot it at intervals and lay it alongside your string and cast across. I believe that a BSS guage is available from Buck & Ryan...

Edited by Bloggsworth, 12 September 2011 - 21:50.

[David Beard]

Josh, although the regular posters on here know a lot about racing - car and driver histories etc, they aren't generally that hot on the technical minutae.

Oh dear, is that your impression, Duncan? We should all try harder then...

Sad reflection on the merits of TNF if you are correct.

Edited by David Beard, 12 September 2011 - 22:03.

[Tony Matthews]

I dont recall those Lotuses using adjustable brake bias. They did use driver adjustable rear anti role bars and this was an idea introduced by Andretti.

Lotus 79 brake bias adjuster. Photographs of the first chassis being built don't show this, but I can't ascertain when it was added. There is quite a time gap berween my reference shots.

Edited by Tony Matthews, 12 September 2011 - 22:31.

[D-Type]

Oh dear, is that your impression, Duncan? We should all try harder then...

Sad reflection on the merits of TNF if you are correct.

Just look at the relative frequency of discussions on various topics.

For example, how many forum members understand the difference between the strength and stiffness of a chassis?

[Roger Clark]

Lotus 79 brake bias adjuster. Photographs of the first chassis being built don't show this, but I can't ascertain when it was added. There is quite a time gap berween my reference shots.

Is that driver-adjustable?

An article in Motor Sport, Dec 1979, said that the Ligier JS11 and the Tyrell 009 had driver-adjustable brake balance. It was an article about cockpit layouts and the fact that DSJ mentioned it for these two made me think that it was unusual He gave a detailed description of the Ferrari and the Williams without mentioning it.

Patrick Head was quoted as saying that the Williams didn't have driver-adjustable anti-roll bars as they didn't want the drivers fiddling as bout with that sort of thing.

[Tony Matthews]

Is that driver-adjustable?

Well, the Bowden(?) cable runs from the brake pedal assembly to a large knob on the dash...

[DogEarred]

The formula for the bias v lift is simply 'pi x 0.5682 squared + the sum of the diameter of the offside front and rear side near wheels. Minus tyres of course.

Of course, this will take a negative value in the southern hemisphere.

[Joe Bosworth]

Author Colin Campbell in his book, The Sports Car Its Design and Performance, refers to ¨... easy adjustment of the braking distribution operated from the driving seat...

This from the Fourth Impression printed in 1955.

So driver adjustable bias was not unkown then.

Regards

[David Beard]

Well, the Bowden(?) cable runs from the brake pedal assembly to a large knob on the dash...

Perhaps it ran back to the pits to allow Chapman to make the adjustment?

Seriously though, rather than a Bowden cable, wouldn't it be a speedo drive type cable?

Edited by David Beard, 13 September 2011 - 06:51.

[2F-001]

re. from-the-cockpit adjustable anti-roll...
I think Lotus introduced that on the 77* (input from Andretti, perhaps?) but I don't imagine that was the first ever instance (even if it was for Lotus). The 77 was built with practically everything 'adjustable' to some degree, so it wouldn't be surprising if they'd done something with brake balance - yet the 78 doesn't appear to have cockpit provision for it.

(*Possibly gleaned from Peter Wright's book, or maybe 'Theme Lotus' - I don't recall.)

Edited by 2F-001, 13 September 2011 - 07:25.

[Roger Clark]

Well, the Bowden(?) cable runs from the brake pedal assembly to a large knob on the dash...

Then it must have been. Apologies

I find it strange that it wasn't mentioned in DSJ's description of the 79, despite giving a lot of space to the adjustable anti-roll bars ( he liked that sort of thing). I didn't see any mention in Theme Lotus, either

[David Beard]

I find it strange that it wasn't mentioned in DSJ's description of the 79

Perhaps because it wasn't something new?

[2F-001]

FWIW, Sal Incandela's book (pub. '82) merely states that cockpit-adjustable brake balance** was introduced "some years ago" (this is thinking in an F1 context). Sounds like the sort of think that Mark Donohue might have experimented with, although I don't remember a specific example from his book.

**Edit:
Apologies - I've revised the above: the reference in my first sentence was supposed to be in relation to Brake Balance (not anti-roll, which I originally typed).

re: anti-roll - Porsche 917-30 had the rear bar adjustable from the cockpit at the end of the 1973 season, but I don't know if this was something Penske had tried previously on another car.

Edited by 2F-001, 13 September 2011 - 09:01.

[Bauble]

Of course, this will take a negative value in the southern hemisphere.

Doggy,
The question of 'how long is a piece opf string' has little resonance in the Antipodes, for as long as it can hold up a pair of trousers, nothing else matters.
Mind you I have read of a store in Bongalonga that sells string in four sizes; Overweight, Fat, Obese and Gir outa 'ere, ya fat git!

[2F-001]

So, David - is this now "Technical Nostalgia Forum"?

[Tim Murray]

An article in Motor Sport, Dec 1979, said that the Ligier JS11 and the Tyrell 009 had driver-adjustable brake balance. It was an article about cockpit layouts and the fact that DSJ mentioned it for these two made me think that it was unusual He gave a detailed description of the Ferrari and the Williams without mentioning it.

Patrick Head was quoted as saying that the Williams didn't have driver-adjustable anti-roll bars as they didn't want the drivers fiddling as bout with that sort of thing.

According to Doug in History of the Grand Prix Car 1966-85 the Williams FW07 had adjustable anti-roll bars and brake balance. From his description, the brake balance adjustment mechanism sounds the same as in Tony's Lotus 79 photos:

The conventional brake balance bar was modified to accept a Smiths tachodrive connected to a knurled knob on the left-side dash frame, lower than the instrument panel. By winding this control to left or right the driver could juggle his brake balance as he pleased while in motion. With his front and rear anti-roll bar adjusters also available for fine tuning one could picture his controls as having more in common with an aircraft pilot’s than a road car driver’s.

[Allan Lupton]

re: anti-roll - Porsche 917-30 had the rear bar adjustable from the cockpit at the end of the 1973 season, but I don't know if this was something Penske had tried previously on another car.

Not new in 1973 but maybe it was for Penske: as I wrote in post no 7, Connaught used it in 1953

[llmaurice]

Perhaps it ran back to the pits to allow Chapman to make the adjustment?

Seriously though, rather than a Bowden cable, wouldn't it be a speedo drive type cable?

Certainly quite a strong "speedo" drive type of cable . I can say that our 1971 713m March had one and I'm pretty certain that Formula ford used them from day 0ne so F1 MUST have used them from prior to the FF era otherwise it's almost impossible to control a rear engined S/Seater in the wet without being able to change bias at will as we know to the cost of numerous nose cones !

[2F-001]

Sorry Allan, I did see that but forgot! Getting mixed up with brakes didn't help me there...

[Bauble]

I think you may be wrong, the diameter of the string will surely affect the degree of available stretch and therefore have a concomitant effect. The best way to measure a piece of string is to purchase a length of tarred rope, knot it at intervals and lay it alongside your string and cast across. I believe that a BSS guage is available from Buck & Ryan...

Bloggy,
I may be wrong? No way mate . You are wrong. Sorry if I sound offensive (mind you I don't care if I am), but the pi equation must stand true, as long as ambient temperature is maintained at 20.379 degrees below ultimate freezing point, at a height of 75,798 feet above sea level,on Bournemouth beach at high tide on April 1st in any leap year.

I see your point about knotted tarry rope, however, the theory was disproved in 1968 by a group of top scientists from Luton University. They found that it was impossible to hold the rope without getting sticky fingers making it extremely difficult to eat their sandwiches.

I see that there have been some on this forum who have cast doubt on the technical ability of us TNF's, but I think the esoteric level of our discussion has proved we is clever.

Kind regards,

bauble.

[2F-001]

I think String Theory may be a touch *too* advanced for the current topic, though. And no "thread" puns please.

[xj13v12]

The Mercedes Moss drove in the 1955 Mille had individual squirters for each corner to free up sticking brakes.
The Tilton adjuster has been around a long time, I thought back in the 1970s and the question relates to driver adjustment. I had a Modsports car with one fitted.

[Tony Matthews]

Well, the Bowden(?) cable runs from the brake pedal assembly to a large knob on the dash...

Seriously though, rather than a Bowden cable, wouldn't it be a speedo drive type cable?

Absolutely right, I couldn't think what I was trying to say, which is why Bowden was querried! It was quite flexible though, as its route was convoluted...

Anyone want the anti-roll bar adjuster too? Oh well, someone might.

The fronts were adjustable too, on this chassis.

Tim Murray. According to Doug in History of the Grand Prix Car 1966-85 the Williams FW07 had adjustable anti-roll bars and brake balance. From his description, the brake balance adjustment mechanism sounds the same as in Tony's Lotus 79 photos:

It always intrigues me the way someone comes up with the solution to a problem that cannot be easily, cheaply bettered, so everyone adopts it, like the brake balance adjustment system! Anti-roll bar blade arms, for another.

Edited by Tony Matthews, 13 September 2011 - 12:45.

[Roger Clark]

Not new in 1973 but maybe it was for Penske: as I wrote in post no 7, Connaught used it in 1953

AL10 had a device to enable the driver to adjust the roll stiffness, but not, presumably, through an anti-roll bar. Is such a device compatible with a de Dion rear axle?

Was it Salvadori or McAlpine who drove AL10 at Monza?

[doc knutsen]

FWIW, Sal Incandela's book (pub. '82) merely states that cockpit-adjustable brake balance** was introduced "some years ago" (this is thinking in an F1 context). Sounds like the sort of think that Mark Donohue might have experimented with, although I don't remember a specific example from his book.

**Edit:
Apologies - I've revised the above: the reference in my first sentence was supposed to be in relation to Brake Balance (not anti-roll, which I originally typed).

re: anti-roll - Porsche 917-30 had the rear bar adjustable from the cockpit at the end of the 1973 season, but I don't know if this was something Penske had tried previously on another car.

The Brabham BT 21B I once owned had adjustable brake balance bar fitted as standard. It was by no means a newfangled concept at that time (F3, 1967/68). Carroll Smith's book "Prepare to Win" came out in 1975. It featured detailed drawings on how to make driver-adjustable ARBs - as well as explaining how to set up the F/R brake balance using the brake pedal balance bar for fine adjustment.

Edited by doc knutsen, 13 September 2011 - 16:25.

[Allan Lupton]

AL10 had a device to enable the driver to adjust the roll stiffness, but not, presumably, through an anti-roll bar. Is such a device compatible with a de Dion rear axle?

Was it Salvadori or McAlpine who drove AL10 at Monza?

Quite right I should have done the homework before posting! Johnny Johnson wrote:
A8 was used for suspension experiments, and was fitted with a roll freedom rear suspension, in which longer reaction levers on the torsion bars were linked by a compression tube over the top of the chassis, so that in 'bump' they reacted against each other, but in 'roll', they moved as one. From this developed a variable roll stiffness mechanism controlled from the cockpit for which a patent application was made by Connaught Engineering in the names of R. E. Clarke and C. E. Johnson, and this mechanism was fitted to AL10. I do not think any driver ever used the roll control, and most had no idea what it was. It is still fitted to AL10 and I am told that it Is effective. R. E. C. was attempting with this system to evolve control over the under/oversteer characteristics, in order to adjust the handling to the differing needs of drivers as well as the the demands of circuits.

That said, he doesn't explain how any roll stiffness was introduced, let alone how it was controlled.
In cars with rollbars where the bar adds stiffness it would be easy to make the input levers with controllably variable length, and there is no reason not to have that on a de Dion axle or any other system.

Similarly, at Monza Salvadori drove a long wheelbase carburettor car and AL10 was driven by McAlpine.

Edited by Allan Lupton, 13 September 2011 - 17:32.

[Ray Bell]

Originally posted by xj13v12
The Mercedes Moss drove in the 1955 Mille had individual squirters for each corner to free up sticking brakes.....

Not exactly...

The squirters were installed in the W196 cars, possibly also the 300SLRs, but they might have had narrower drums so it would bear investigation.

Their purpose was to prevent cracking the ultra-wide brake drums in the warming up early laps of a race. Here's Moss' description of it from The Design and Behaviour of the Racing Car:

Due, Pomeroy thinks, to their exceptional width, they had to be warmed up rather gently if cracking of the drum of the liner was to be avoided. For this reason one of the few instructions we had as drivers was not to use the brakes too hard at first, and not to worry if anyone campered by on the first lap or two as they could always be taken later. And believe it or not we also had some dear little plungers on the dashboard which fed oil into the brakes so that they would not be too fierce and lead to cracking.

[Tony Matthews]

In cars with rollbars where the bar adds stiffness it would be easy to make the input levers with controllably variable length,

Has that been done, Allan? It probably has, but I am only familiar with the 'rotating blade' type of lever.

[Nigel Beresford]

Has that been done, Allan? It probably has, but I am only familiar with the 'rotating blade' type of lever.

1975 McLaren M23 ...

Thanks


Nigel


hosting images

(Image by Connect Images)

Edited by Nigel Beresford, 14 September 2011 - 08:01.

[xj13v12]

Did they use this on the M24 too Nigel?

[Roger Clark]

Not exactly...

The squirters were installed in the W196 cars, possibly also the 300SLRs, but they might have had narrower drums so it would bear investigation.

Their purpose was to prevent cracking the ultra-wide brake drums in the warming up early laps of a race. Here's Moss' description of it from The Design and Behaviour of the Racing Car:

The squirters were fitted to the SLRs at Le Mans, following some problems with grabbing brakes in the Mille Miglia.

The quote in Design and Behaviour is the only mention I know of their being fitted to the Grand Prix cars.

[Nigel Beresford]

Did they use this on the M24 too Nigel?

I don't know about the adjustable lever length type, but they did run an adjustable blade type. I don't have any contemporary pics to show this, but there are pics on the net showing the restoration of an M24 which clearly show an adjustable blade FARB.

Edited by Nigel Beresford, 14 September 2011 - 09:08.

[Roger Clark]

The squirters were fitted to the SLRs at Le Mans, following some problems with grabbing brakes in the Mille Miglia.

The quote in Design and Behaviour is the only mention I know of their being fitted to the Grand Prix cars.

Since writing this, I have found them described in Setright's The Grand Prix Car. I could find none in Ludvigsen's Quicksilver Century, nor in Jenkinson's contemporary reports, which I would normally regard as definitive for these cars.

[Bauble]

Since writing this, I have found them described in Setright's The Grand Prix Car. I could find none in Ludvigsen's Quicksilver Century, nor in Jenkinson's contemporary reports, which I would normally regard as definitive for these cars.

From a rather ancient memory I recall that Mercedes did indeed use 'squirters at Le Mans in 1955, as they found the disc's on the D-Types gave much better retardation, and i trying to compete led to locking brakes.

bauble.

[Tony Matthews]

1975 McLaren M23 ...

Thanks


Nigel



(Image by Connect Images)

Than you, Nigel! I don't remember seeing that before, or on any other car! The blade system is, I think, a simpler, neater solution.

[doc knutsen]

Than you, Nigel! I don't remember seeing that before, or on any other car! The blade system is, I think, a simpler, neater solution.

Difficult to make the twisting blade system anything but either full-stiff (blade vertical) or full-soft (blade horizontal). The McLaren design, using a tubular ARB, is fully adjustable with precise levels of stiffness all the way.

Edited by doc knutsen, 14 September 2011 - 20:15.