What does “brake by wire” mean in these new F1 cars and how does it affect the drivers?
Posted By: James Allen  |  05 Feb 2014   |  11:45 am GMT  |  202 comments

Felipe Massa’s quote at the weekend about the new ‘brake-by-wire’ systems on the 2014 F1 cars taking some getting used to has sparked a lot of discussion on the JA on F1 site, with readers wanting to know more about what it is and how it works.

Let’s start with an explanation from the Sauber F1 team, “The braking system concept is totally new, taking the form of a brake-by-wire system for the first time at the rear wheels. This has become necessary due to the significantly increased performance of the ERS, which requires much greater variations in rear wheel braking torque than previously. With brake-by-wire, an electronic system measures how hard the driver presses the brake pedal and then – using the additional information from energy recuperation – determines in a split-second the amount of braking pressure that should be fed through to the rear brake callipers.”

In other words, because the ERS (Energy Recovery System) is so much more powerful on these new cars compared to the KERS on the 2013 cars, harvesting energy when the car is braking – 161bhp of energy compared to 80bhp with the KERS – it is essential that the engineers install a system to compensate for the powerful effect that has on brake balance and braking stability. This makes it acceptable for the driver and doesn’t destabilise the car with a sudden balance shift. A lot of the lap time in modern F1 comes from stable braking.

Massa’s quote was: “The brakes work in a different way. It’s electronic brakes, brake-by-wire, and I still need to improve the way I’m braking because it’s different. It’s a little bit strange sometimes,” he said.

So, how does it work?

An F1 car has two brake systems for safety – front and rear – so that if one fails the other will stop the car. For 2014, the rear brake system has the brake-by-wire, which assesses how much brake pressure the driver has called for when he presses the pedal and an electronic system modulates the power to the rear brakes, allowing for the ERS effect, that is taking energy to charge up the kinetic motor generator unit (known as MGU-K). It smooths out the process, slowing the car in a consistent way at the same time as ensuring the maximum energy harvest for the ERS.

Ideally, the driver would feel nothing unusual with this system, in that it should provide consistent, stable braking on demand. The job of the new rear brakes system is to ensure consistency. Some people might argue that the electronic assistance to the driver makes it a “driver aid” and in the sense that without it, it would be difficult to maintain a brake system that the drivers would be happy with. This damps it out. But as it’s written into the regulations it doesn’t fall foul of the regulation saying that the driver must drive “alone and unaided” – a rule that prevents the use of traction control, ABS and countless other technical goodies.

Here is the exact wording of the new technical regulation on brake by wire.

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Surely there has to be oppotunity for creation of some new electronic trickery in this area, im sure soneone will find a loop hole if not already done so


If there are electronics involved there are opportunities for skullduggery.

Why can we not go back to "drivers cars", as one former F1 champion has quoted "F1 is now artificial".

My first GP was Aintree 1955, last year I didn't watch one race.

I have seen Fangio, Moss etc, they were true racing drivers, they had a feel for a car, as Stirling Moss once said, "Cars themselves bore me, it is what I can do with them that I find interesting".


This, in and of itself IS electronic trickery. It's meant to be

My question is, can the driver still look the rear wheels or is the essential legal antilock brake for the rear wheels. The implication re: driving style doesn't change much. As a driver, your focus under braking is usually the inside front tire on turn in..


My understanding is yes. It is more likely to occur in the wet, but if the bias is set too far to the rear then the rear can lock.

An interesting control problem would be working out the way to allow a driver to set a quite rearwards brake bias and use the throttle to control the level of rear brake force - I believe Schumacher did this a lot, and may have been the way Hamilton backed the McLaren into corners in 2007.

The reduced rear grip for 2014 may mean understeer is rarely an issue and this technique is not needed. It isn't likely to be used regularly in racing conditions as the fuel penalty is too great, but there might be a benefit in qualifying for some tracks.


What you will see is brake bias set full front (or ECU controlled) with ECU/ABS control of the rears. ABS by another acronym is still ABS. Should make for crazy deceleration. Maybe they wil need to get tracks to replace 50 metre boards with 25 metre boards in braking zones! Big kahunas instead of skill will be the order of the day. Good luck sorting out issues in this area in 7 days Red Bull, considering they never really got a handle on KERS in Webber's car. System failures may quite possibly be mighty spectacular if the car defaults to fronts only if electronic failure occurs.. F1 is headed in the wrong direction with this technology. It sounds crazy complex. I still think turbo, methanol (renewable fuel) cars (ah la the ol' Indy cars) with F1 build quality, exotic materials etc, combined with the best drivers in the world is the way to go for the spectator.


Not sure methanol would be accepted in F1. When it burns its practically invisible, unlike the spectacular glowing red of the hydro-carbon petrol. Also, methanol is not used on many production cars, so there is no benefit to the production car industry. I think the way of the future for F1 - perhaps 10 years time - is a hybrid electric and hydrogen fuel cell.


You hardly ever see the rear wheels locked under braking so some sort of covert ABS isn't really going to achieve much.

And braking one side harder than the other might be advantageous in certain circumstances but the same effect can probably be done thru existing electronic diffs.

So it's hard to see what they could do at risk of being found out.


James, wont the drivers lose the "feel" on the brakes like locking and so on??


Kimi is experiencing similar "issues".


It is analogous to the four wheel steering on the Porsche 911 GT3. The front wheels have a mechanical connection to the driver and the rear wheels have an electronic one that is based on what the front wheels are doing.

So far we have had Massa comment on it. It could be that the other teams have better systems, and Williams' front brakes may not be what Massa is used to, in the same way Hamilton thought the Mercedes brakes were not as good as the McLaren ones.


That is the challenge for the engineers

Massa said that the feel is different.


I agree. How is that policed? And will we still see differences in lap times coming from drivers' braking abilities?


It'll be policed via the SECU. Remember that FIA control the software for that. If they suspect or find out that there's things going on they don't like they'll have the software modified to prevent whatever it is.


OK but presumably, the system wouldn't allow the rear axle to lock up, because a non-spinning axle won't generate any electricity anyway... so could it be argued that it has a similar effect to ABS (even though the operation of the latter is completely different)?

Also, does this have a knock-on effect elsewhere? For instance, would teams now reduce the size (and therefore, weight) of the rear brake discs and/or calipers? I realize there might be phases in the race when there is less need to harvest energy (or if the ERS system simply fails, hopefully only for a few laps), so the physical brakes would still be needed...

Finally, I was under the impression that brake-by-wire would make things slightly simpler, for the driver, so why does it take getting used to?


My understanding is that it would be possible to completely lock the rear brakes with the new system if the brake bias, wet track or bumps created the situation for it to occur. The brake force demand is proportional to the front demand. If that force exceeds the inertia in the wheel then the wheel will lock. Now once the brakes lock and tyre starts sliding the absence of ERS braking may be enough to mean that the wheel starts to rotate again, but I suspect it is more likely that rear brakes will be strong enough to continue to keep the wheel locked.

A knock-on effect that has been noted so far is that the reduced rear brake temperatures mean that rear tyres are losing temperature quite easily. Rear wheel toe-in settings may be increased to distort the tyres more to generate more heat.


Actually, I may have inadvertently answered my own question (one of them anyway)... I recall being a new, 18 year-old driver, driving along a quiet road, realizing that I was about to miss a turn... then braking hard, AND downshifting from 4th straight into 2nd. In a rear-wheel-drive car. On a wet road. When I let go of the clutch, it felt like I'd pulled the handbrake. It really gets your attention...

So presumably that's what Massa meant: the physical brakes are still there, but another very powerful system wants to under-rotate the rear axle at the same time. The electronics ought to make it easy, but perhaps getting them right (for the right track surface, the right incline) involves a little bit more work than simply adjusting the brake balance...


Is that called compression braking? - I snapped a diff doing this...not fun - wonder how many other areas of an F1 car have had to be beefed up to handle extra workload.

Fernando "150%" Alonso

As far as i know, Ferrari has smaller disc brakes for F14T compared with the ones they fitted the 2013 single sitter.


Perhaps the Ferrari torque blip is done by electric motor rather than petrol. Torque blipps are very poor for fuel consumption. using electricity while breaking might help them harvest more of it and use it right away for blipps, thus bypassing storage limits.


The Ferrari F1 F14 T sounds a lot different to the other cars under braking. Why is this?

It is incredibly smooth on the downchanges. Everyone else is blipping the throttle a lot more and it's difficult to say why the Ferrari is so smooth in comparison.

All the cars have a zero torque loss upshift, seamless shift, but nobody has done that on the downshifts. With the ERS recharging from the rear wheels and the need to downchange under braking, it now might be a good idea.

We don't know for sure, but perhaps Ferrari is ahead of the game with such technology.


Good example


If this sysyem is adopted by the passenger car industry it will certainly have the Kwik Fit fitters scratching their heads !!


Passenger cars have had brake by wire technology for years now,just the way hybrids have had KERS. And from Toyota's own admission, far more sophisticated form of energy recovery system is used in their road cars compared to F1 cars.


Which is a laughable statement but, of course, they would not say otherwise after they went home crying.


Passenger cars are already using brake-by-wire.


No, the engine manufacturers have their own version of ERS, so it goes without saying that the braking technologies to harvest for ERS would be different.


Interesting article. But I can't read the exact wording on the new technical regulation it's too blurry on my phone. 🙁


Get an ipad


Don't worry - it's blurry preiod 🙂

The regulations are easy enough to find on the official F1 or FIA site.



Preiod is a new word I just invented meaning "everywhere" as has nothing to do with the similarly spelled "period".


Now that Ron is back in F1, perhaps he can use it in one of his interviews!


I didn't have a clue what brake by wire was and it was something that has been needed to be explained. Thank you James


Hi James - are the electronics that do brake-by-wire provided by the Mclaren ECU? If not - how would you police whether or not teams are putting 'driver aids' - such as ABS - in to the electronics?


The ECU IS where the brake by wire is managed. It's in James' picture of the rules (the last provision).


No, the engine manufacturers have their own version of ERS, so it goes without saying that the braking electronics to harvest for ERS would be different


Or anti wheelspin


Good question. That is what I am wondering.


Nicely covered James 🙂


I'm fascinated by the new tech coming out from this season. I for one am a fan and view these new regulations as a formula. It is meant to be difficult and challenging formula. That's why it's Formula One.


But surely in essence this does make the system a form of ABS because the system is giving the driver enough pressure to stop the car but not too much to lock the rears. This would have 2 effects 1.locking the rears would mean loss of control 2.when the rears locked there wouldn't be any harvesting of the batteries at that particular moment in time so taking away much needed time during a lap to charge the system to its optimum level thus being unable to run the ERS at its optimum operating level. So the engineers would be working on a system that didnt lock the rears gaining more lap time.


Given the new ERS brake by wire on the rear wheels is all but essential. A driver could not hope to predict how to shift the brake balance effectively in a race situation and could be dangerous without it potentially putting drivers into the wall when they discover they suddenly have less than effective brakes. The issue facing drivers now is that the feel of this combined system does not feel normal, and indeed probably not as consistent as was hoped for. Like all new systems there is room for improvement just as there was for ABS on road cars it still has someway to go before the ideal is reached or so I believe


Does everyteam use the same system, or there´s different interpretations of the system?


Any comments from Hamilton or Mercedes on this as braking was a big issue for him last year? It sounds like the last thing he needs at a time when he would hoped to have sorted out the feel of the brakes going into a new campaign?


Well he doesn't have a choice, but any disadvantage is countered by the fact all are in the same boat. My guess is that the new COMBINED system does not exactly feel normal, and perhaps needs further refinement to be ideal. That said both Mercedes drivers seemed to take to the car like a duck to water, but any abnormality will manifest itself in lost time in the braking zone as they err on caution. Providing the system is predictable with good feel they should be able to adapt to it. It will be interesting to see how things develop all round!


At least he gets to start from scratch like everyone else. He's abig boy now and will have it down in no time. Seb, on the other hand is yet to experience it 😉


Ta for the explanation, although it seems that Renault have devised a slightly different system for stopping the cars on track: Break by fire 😉


Ha ha! At least Adrian and Regie have found a novel way of getting heat in the tyres as well!!!


I wondered whether Renault had not translated the regulations correctly (what with being French an' all ) and have developed a system for harvesting energy when breaking:-)


I thought that was an afterburner!


Good thinking 🙂

That answers the question of how the engineers are going to gain a performance benefit from these new regulations.


Better yet, not start in the first place!


Thanks for the laugh.


I don't think any Renault engine has generated sufficient heat yet to burst into flames.


Well something was on fire at the back of the Bulls and there was a fair bit of smoke. So whatever it was , it was getting hot.


It was an exaggeration based on a play on words (Brake by wire / Break by fire) but still the key word there is "yet" 🙂


Iremember vaguely one driver mentioned that it takes about 110kg of foot pressure to brake from a straight into a corner. Will this new system require less force application?


Do you think teams will find a way to sneak in some sort of ABS via the brake-by-wire system?


Some people is saying Ferrari has already done it. Track side comments in Jerez said Ferrari had a different sound than the rest under braking and it looked so stable, and people is making their own conclusions.


Great stuff!

Let's see how the guys will adapt on this changes.


Could you make the technical regulation image smaller please - it's still possible to read it 😉

So will we have ABS at the rear, and so an end to seeing rears locking up? It seems to me that it's going to be almost impossible not to have ABS, as locking a wheel will have a big effect on the energy recovery and the two are now so closely integrated.


Well I remember hearing someone say that this year, the ERS harvesting isn't controlled by the driver. Instead of the KERS settings on the wheel of last year and before, it would adjust itself as needed. If that's the case, I'm struggling to see how they wouldn't effectively end up with ABS at the rear.


Following a motor bike accident in July 1993, I am now disabled and a full time wheelchair user. I am classed as a tetraplegic but I do have movement in both arms, with my left arm a small movement to the back and to the front, and about half normal movement with my right arm. After leaving hospital and having my right leg amputated below the knee I thought my driving days were over.

In 1995 I was pleased to find out that I would be able to drive and I ordered a Ford Transit Mini-bus to be adapted with the items that I needed to be fitted so I could drive. I was told that my braking and accelerating would be by 'fly by wire' which I didn't understand until my mini-bus was ready for me to drive.

Basically 'fly by wire' means that there are no hydraulics only electric signals along wires which operate the brakes, there may be some hydraulics to operate the last bit of the operation. The signals also open and close the accelerator fuel supply to the engine. So when you operate either there is no feeling through the pedals of anything happening. You just have to guess how far to push the brake and accelerator pedals. With the brakes expect a number of emergency stops unless something can be put in to give a fake feeling. It's very strange and takes a while to get used to.

However, in F1 as the 'fly by wire' only operates the brakes on the rear wheels I doubt it will be all that difficult for the world's best drivers to get used to.

I hope this makes it a bit easier to understand and I apologise for going on a bit!


That's interesting Bruce. I imagine that the system you have feels like a Citroen used back in the late 70's/early 80's. That wasn't strictly "brake by wire" but was so heavily servo-assisted it felt like it. Just a button (not a pedal) on the floor and the first few times you touched it you just stopped!

But, as you say, you got used to it.


Thanks for the info, much easier to understand for us mortals than more tech bits


Bruce, very sorry to hear about your unfortunate accident, but very pleased to hear you still have mobility in terms of being able to get around, and being able to get out and about and enjoy the country. I think its fantastic that such a noble and clever piece of engineering is benefiting disabled people to have a decent quality of life; this is the great thing about thoughtful, clever engineering is that it benefits everybody in society for the greater good. That is ultimately the triumph of the human spirit. F1 and motor sport in general is ultimately the test bed of new technology to benefit human beings, and your story reflects the benefits to quality of life technology brings. Your essay is very thorough and insightful Bruce, hope to hear more from you.


Thanks for that insight I was wondering how the system worked. Are the front brakes still a "normal" system then?


James, some drivers (e.g. Schumi, Vettel) use the brakes to 'turn' the car. Will that work with the new system?


It seems like it would be possible for this system to adjust the braking force differently for each rear wheel, based on steering input, to have some effect on steering.

I have idea if that would actually help anything of course...


great question! As we have seen, top-tiered have used this to great success in the most recent formula!


A good question. I'l find out



What happens if a driver slightly presses the brake pedal out of the comer at the same time of pressing the gas pedal and then that would be a form of helping traction by activating the system?


That's an excellent idea and it could theoretically work, but the ECU prevents over lapping brake and throttle application


I don't think so because as soon as you press the accelerator, the MGU-K stops harvesting (which provides the retardation) and could even be feeding more power into the driveline.

So you would only be getting the 'ordinary' hydraulic braking.


It now makes sense why the teams have been saying that the 2014 cars are complex for I can't begin to wrap my head around a system that applies the required brake pressure whilst harvesting 161 bhp all in split second.

Anyway, I guess the problem with the new brake system has to do with the reduced downforce in the rear of the cars.

I think the drivers have gotten used to a stable rear that now when they press the pedal on the 2014 cars, the back of the car slides.

The only conclusion I can come up with is that the new brake by wire concept is that it will favour those pilots that prefer a loose rear.


A recipe for lots of problems, some possibly dangerous eg. the ERS decides to lock up the rears at 200mph( or not brake at all).

I think we will see that adrenalin is brown!


The brake-by-wire on the rear wheels only was needed because the much bigger harvesting of the bigger capacity MGU-K will affect the braking to an extent that the normal brake balance adjuster would not cope.

The rear wheels only brake-by-wire will be an addition to the normal hydraulic master cylinder pressure braking system for safety reasons.


“alone and unaided”, yet they use semi-automatic transmissions and anti-stall.


Sounds like a nightmare! If there is one area where 'digital' should not replace 'analogue' - it's in braking! I don't believe for a second that the software guys could make a 'digital' brake-by-wire- system feel as intuitive as a normal analogue braking system.

With an analogue system, the last time you jumped on the brakes informs the intuitive input for the next time you brake - if the ERS requirements are different between the two braking events then it's a big ask to perfectly normalise braking feel via software that switches compensatory hardware somewhere inline of the braking system - too many variables man!

That said, it's a good opportunity for the resident team hacker to sneak some hidden code into the standardised control system (it IS standardised for all teams isn't it?) to provide brake-assisted 'turn-in' to tighten the line for some dramatic mid corner overtaking! 😉


Why not? It's essentially a precision problem. Which is a matter of time, before it can provide considerate amount of other benefits beside similar breaking.

Same as with Renault engine, if it doesn't start, it doesn't mean it will be worse when it does.


Easier said than done going by the honesty of some driver accounts.

It (designing a digital system that allows the driver to predict the NEXT braking effort required), could be just a 'precision problem' if the input variables can be predicted and controlled ...and if all of the variables are known...and if it can be made to suit all driving styles (another variable)..if it were otherwise straightforward the drivers wouldn't be talking about having to 'adapt'.



How will this affect the late breakers like Lewis, and is the W05 still using the "FRISC" suspension, if so there is a lot that can go wrong in terms of understanding how much and when to apply the brakes and maintain the car stability not detrimental to a good lap time. It will be interesting to see how the drivers adapt their driving styles.


This technology will be ABS and traction control and is the next F1 arms race. They may not call it traction control, but the engine mapping and electric power, turbo boost etc will function that way, only deliver what is required and no more. The brake by wire will be tuned to the drivers style to deliver damn near ABS characteristics. Sure you will be able to overdo it, but it will be tuned to the nth degree of the drivers style by the end of the season.

Mercedes and Ferrari will have the early lead because they have miles to test how to match the braking to a feel that gives the driver confidence and data to perfect the simulator for practice and development of the track. But the championship, once reliability is taken into account, will be the team and driver that makes the most effective use of this technology to get the fastest laps. The mapping of all this for a driver that can optimize power delivery and braking with driving style will compensate for being down on power in a big way. If the drivers don't commit a lot of time to the simulator this season they wont learn the optimal way around a track which wont be the same as in previous years because new methods and refinements are now possible to get 10ths more.


Totally agree, its allowing ABS and TC in via the "back door", or should that be "rear axle"? Also, somewhat ironic that hydraulic power steering is allowed, but electric PS is banned. If you're going to allow electronic sensory on the rear axle, why not the front? Very inconsistent rules if you ask me, but this is the FIA.......


rear differential traction control has been used ever since they started using programmable ECUs.


If u think a differential is traction control then u dont know ish about cars


Of course! I forgot electronic differentials and their control units could be "tweaked" depending on circuit layouts, weather conditions, etc......you're right, effectively the last few years the cars have had TC in all but name


Great post. Most of it I already knew, good to add in the piece about the driver aid argument 🙂

I am hoping more posts are coming shortly about the MGU-K, MGU-H and the energy storage systems explaining it in detail and how it works hand in hand with the v6 engine to produce fuel efficiency. I gather, when explained properly we could change the minds of some readers who still believe being in the pinnacle of motor-sports means still being fast and loud!

Hopefully the FIA will let the manufacturers develop on what they have now freely, and we'll get most of the lost speed back, ending up with an engine Formula that is the best across any form of Motor-Sport. F1 needed this change.


I completely agree with you. I would also like to hear James' thoughts on the possibility to use off throttle turbo blowing in conjunction with McLaren's clever rear aero suspension!

I spoke to my friend who works in the pit crew for one of the big teams and he said the new engine's sound amazing. I think most of the people commenting negatively about it are doing so with out actual having heard them. To me, through my headphones, I thought they sound dirty, really dirty


My understanding is - Turbo engines don't blow like normally aspirated ones, the pressure is used for the turbo/ERS etc.


What is to stop one team configuring this to act like ABS for the rear axle?


The same reason your car doesn't have ABS on the rear wheels .... It doesn't need it.


the only thing that has stopped any team doing this is a desperate lack of money. So the only team not doing this maybe Lotus - getting a car with a decent potential on track is the first priority.

Configuring all systems on the car to gain maximum benefit is essential for all teams.


Okay, one can understand the need, under the complex conditions resulting from the new complex power units, etc.

However, previously, this would definitely be considered a drivers aid.

Furthermore, just where is the line between optimizing the energy recovery system, and drivers aids?

For example, coming out of a corner with these new, super-torque power units, wouldn't it be reasonable to use the similar system as in braking, to modulate the power to the rear wheels so as to harvest the maximum amount of power, where the maximum amount of power to the road is that immediately prior to creating wheel-spin?

Will this be policeable using the ECU?

Even if it can be observed, won't the power unit manufacturers be able to say they were just following the mandate of the new rules?

So we will have appeals after appeals to the FIA to rule on systems this year, until operational guidelines and tests are developed governing how this line is drawn, non?


I believe that this year the drivers will no longer be able to employ the KERS by use of a button?? I guess that means that goes for the harvested ERS energy as well? So does all the harvested energy (ERS + KERS) get deployed evenly via the throttle unseen by us? Is it pre-programmed - can they use it off the line at the start somehow? A simple explanation would be great - thanks very much Ian Bunker


This year drivers won't use a button like last year because at total charge the ERS provides about 32 seconds of extra energy, the ERS will be used via the throttle and this could be configured, I don't know exactly the details, but based on a recent interview to Rosberg -see F1.com- seems that the configuration could be modified from the pit wall during the race, and the driver could do something, but I'm not sure about that and what is the rule in this case.


We can assume that drive skill will take another big step backwards.

ABS has been illegal for decades. That hasn't stopped the teams from getting around the rules by using engine braking to create a poor, but working substitute.

Brake by wire will make full on ABS a trivial addition. A small bit of computer code and the drivers will be able to push the pedal as hard as they like without risk of locking up.

For those that don't believe, just look at the braking zones at places like Montreal. There are scallop marks where the tires lock and unlock.

Oh, and every car also has traction control, even though that is technically illegal. When was the last time we saw a car generate tire smoke on a standing start. Traction control.

Another big step backwards for the sport.


"the drivers will be able to push the pedal as hard as they like without risk of locking up."

They'll still lock-up the fronts if they do that. Those are not brake-by-wire..


Hamilton's biggest strength has always been his ability to stabilise the rear end of the car under braking. I'd imagine Rosberg fancies beating Lewis this year if Lewis struggles with brake by wire, like he sometimes struggled with the braking of last year's car.


Very good point. Lewis was complaining (legitimately) about brake feel, and now a new regulation comes in to potentially make things worse for him!


I didn't know there was someone on here who could tell that a complaint was legitimate or not, well done.


Its certainly legitimate for Lewis and Mercedes!


Nowadays cars are complex computers and no longer a mechanical assembly. This is even true for road cars let alone F1 cars.


So it is like computerized brake bias control then? I wonder how the system adapts for different aero loads at different speeds or do I have the wrong image of how this works in my head? Would this mean the driver can only lock the front tires and the back tires compensate automatically? Plus, how would this work with drivers who use the brakes and the throttle at the same time to balance the car (ala Schumacher)? This area is totally interesting!


I dont think it's 'bias' control, just control of the rear brakes. The fronts are still hydro operated and not subject to computer control. As far as I can see, the fronts should still lock up but the rears can be programmed 'not' to lock up in the interest of energy harvesting. Come to think of it, I cant see how any manual bias adjustment (ratio front to rear) can be achieved without screwing up the harvesting process preiod.


but the front brake calipers are functioning on hydraulics?

and rear brake calipers on electronic?

how can they calibrate them? so that all four wheels are biting at the same instance?

software that follows the front bite?

it sounds complex...

hopefully not a grey area that software engineers can exploit.


hahahahahahahah, everything is grey until the definitive line is drawn by a test that can discriminate, in this sport.

that is the nature of the current Formula One process.


James you forgot to mention that there's still regular disc and calipers at the rear wheels, the only difference is that they are now activated by an electric motor, this motor will brake harder or softer compensating for the inconsistencies of the batteries charging.

Also technically speaking horsepower/kilowatts is not energy, it's a rate of energy, for example 1kW=1kJs(1000 Joules per second).

Last year they could harvest and deploy 800kJ, now they can deploy 4000 kJ per lap, which at a rate of 160hp=120kW is good for around 32 seconds.

But here's the catch, the teams are only allowed to harvest half of that every lap (2000kJ) so in the race the power coming from the ERS will actually be 160hp for around 16 seconds, and in qualifying or when trying to overtake someone the batteries will then be fully discharged but it will leave a driver somewhat vulnerable for the next lap.

I just hope the FOM does something to help the casual viewer understand the way energy is deployed and harvested and also show how much fuel is left now that they can monitor that live with the FIA flow meter, I'm an engineer so this is pretty straightforward or me but some people might struggle.


They can only harvest half that from MGU-K but it's unlimited from MGU-H so if they have that system generating energy well they can make up some of that deficit, also 'mid race' when cars are following others, they may not need all the energy available so they won't empty the batteries completely. I thought the unlimited harvest at the turbo was a great incentive to make it work as efficiently as possible rather than just concentrating on how well it stops turbo lag and rely on the MGU-H to do the majority of the energy generation.


there is a limitation to the turbo harvest. Granted it is a little obscure but it is still very effective. The turbo is driven by exhaust gases... which are created by burning fuel. This will mean that the energy that can be harvested from the turbo will vary fro track to track... and, therefore, according to safety car periods. There will be some interesting modelling going on about turning the wick up after a safety car episode.

At what point do you choose to burn more fuel? When there is more than enough fuel to reach the end of the race the car is too heavy (slow). So you choose to burn fuel at a higher rate... which means there is more energy to harvest. Teams will be aiming to harvest as much from the MGU-K as possible as that is without cost... or will they choose to run with smaller batteries at Monaco? - can that be done?


Ok a small correction, the rear wheels are modulated by the ERS systems that sit on top of the battery, not an electric motor as such, but it acts in the exact same way.



Will this mean the drivers won't be shirting brake balance between corners as we saw on a regular basis last season.


James Allison stated in Jerez that Ferrari had a lots and lots of code to write. Is that software related to this brake by wire system? Also to what extent does the brake by wire system need to be rewritten/tweaked from circuit to circuit?


I read on an Italian website that the only problems they had in 4 days were software-related and will do some debugging. Maybe that's what James Allison referred to.

Mechanically, the car seems fine. They also ran a very basic aero configuration, hence the traction problems Gary Anderson mentioned (for ex. they had a 3 element front wing while the other had 6 elements on it). In Bahrain they should have some aero parts and modified engines. So far so good. Also, both drivers gave very similar feedback, which the engineers were very happy about (it didn't always happen when Massa was there). Cheers, Bart


I am not sure if I understand this correctly, but as far as I can work it out the system still starts as a hydraulic system (and remains so for the front end) with a sensor measuring pedal pressure which dictates braking level. At the back end the amount of braking developed by the calipers is adjusted downward by the same amount that energy harvesting applies toward slowing the car. If that is the case, as the driver increased pedal pressure to the point that the front brakes would lock it will also apply that same braking level at the rear - as the rear axle stops spinning the energy harvesting would drop to zero and 100% of the braking force called for by the driver's foot would be applied exclusively to the calipers locking up the rear end....I think 🙂

It should still be possible to lock up the back end if the driver stomps on the brakes - the system just corrects caliper pressure to compensate for energy actually harvested so I don't think it will work as an ABS system.

Or I am completely wrong.......


Its my guess that the braking system electronics subtract the effect of the harvesting from the demand created by the driver's foot on the brake peddle. This would still allow the driver to lock the wheels if too much pressure is put on the peddle and would not enable the system to act like ABS.



Why would you post a miniscule screenshot of the regulations?



Next time you put a screenshot in a blog post, please make it clickable so that it can be expanded and easily read.

I don't like having to zoom, just to read one small regulation clipping. 😉


Surely, being electronic controlled rear brakes; its is already 50% ABS.

Moreover, the harvest system will also be an indirect traction control during deceleration.


Hi all and thanks James for the article

I understand more now but I am still confused ... If the ES harvests energy from braking why would it affect the brake balance. When I think about it it seems like the brakes would still be independently doing their thing and the ES acts after that???

What am I missing? If anybody can help I'd appreciate it 🙂

Looking forward to the new season!



The braking provided by the caliper (traditional) will work in unison with the braking needs for harvesting electricity. To keep the braking consistent for the driver, this needs to be electronically controlled, hence the new braking by wire.

Traditional brakes are a hydraulic fluid line, the driver presses the pedal and this in turn pressurises hydraulic fluid to move a piston in the brake caliper. With these new F1 electrical brakes, the driver presses a pedal which now instead operates a position and pressure sensor, which then transmits info via electrical wire, messaging a control unit which will distribute the braking between KERS harvesting and the rear wheel brake calipers.


Hi both - thanks for the info 🙂

So is it something like some of the energy in the traditional brakes will end up being used to turn the "crank handle" for the ERS ... so the electronics need to balance this out??

It is making more sense now - thanks again


"If the ES harvests energy from braking why would it affect the brake balance."

Because it's only connected to the rear wheels, in a normal car when it slows down all of that energy is transformed into heat by the brakes (and wasted) but here some will be transferred to the battery.

I guess is a little hard to imagine that just "charging a battery" can actually slow down an F1 car but it does, it works in the same way a crank flashlight really, except that is connected to a battery and is powered by the moving car.


Didn't understand the article at all, but then again, I am a bit of a "Jeremy Clarkson"...


I am a fan of Jeremy Clarkson, i watched all Top Gear episodes and all the videos I could find. So I have the strong feeling that if he was so " Clarkson-ian" for real, he would not be alive :).

As for most of the coments on James article, in my opinion,they show the concern that the F1 races (which as any mechanical races with corners, are more a brake pedal contest than a throttle one) will become a race between engineers rather than the actual drivers




You probably know Jezza and Adrian went to school together, I wonder if Adrian has contacted his old school mate and, dear Jeremy, can I bring my new Red Bull round to the Top Gear technology centre as it keeps bursting into flames and can you, Hamster, Captain Slow and all the crew sort if out for me? Thanks very much, your old Repton school mate Adrian.




My main concern is: what happens if a bug or gremlin affects the electrical system? We all know electrics are notoriously unpredictable.........Does the driver loose ALL rear axle retardation? If it does, that is pretty scary to say the least. I know in theory if you are going to have a brake problem its better that to have a problem at the rear rather than on the fronts (I think brake bias is about 60/40 or 65/35 to the front) but still.......remember Michael's failure at Silverstone 1999? Is that possible to happen again? And remember Michael's failure was with the old fashioned yet reliable and robust hydraulics. Does make me shudder.


First, we need to get rid of this attitude towards electronic control system being unreliable. While I am not nieve enough to think that they never fail if the software is written properly it shouldn't fail, unless there is a hardware failure/malfunction (the McLaren ECU that controls the system use to have 0% failure rate, I'm not sure if this is still the case though). When I am modelling the reliability of a system we always set the failure rate for software to 0 this is because it either works or it doesn't work - it is sometimes a big assumption to make but we have to assume it has been done correctly. Fly by wire is very mature technology now as it has been used in the Aerospace industry for decades (since the 1980s I believe) and brake by wire has been used in the Automotive industry for a number of years as well. With all systems that have software in that is safety critical there are certain checks and criteria that must be met and lots of testing is needed as well. The guys in F1 are obsessed with reliability so I am sure they will do all of this and more. It is much more likely that crashes will be caused by the driver braking at an in appropriate moment than the brake system failing. Every day we all rely on electronic control system that could kill us but we don't even think about it. This is another case of people's perception of risk and actual risk being completely out of whack.

Secondly, if you had read James' extract from the technical regulations (I understand if you didn't because it is very hard to read) it says that a hydraulic system must be used as a back up to the powered system.

Sorry for the lecture but it's kind of my job


McLaren did have one problem with an ECU which accounted for one of Webber's bad starts last year, but they did apologise for it.


Yes, imagine this scenario Melbourne 16 March, James commentary on Radio 5: "...........oh hang on a minute, what's this..............oh dear, a nightmare practice and qualifying for Red Bull has been well and truly concluded by both Daniel and Sebastian pulling off on the warm up lap with both cars on fire............"

As for Mark, I always remember when he brilliantly qualified on the front row at Malaysia in his woeful Jag (or as Jezza calls it, a Jaaaaaaaaag), and yet by the first corner he was at the back of the field!


Race starts were Mark's achilles heel - no question - but he did do some brilliant ones while Vettel has also done some dodgy ones.

Frankly with the way things stand right at this second I'll be impressed if either Seb or Dan get off the line in Aus.


Did you notice every time a Red Bull started badly, it was always Mark? With Daniel joining the Bull payroll this year we can ascertain whether Mark was just a rubbish starter or if its a case that Bull is incapable of providing a good starting system to both cars. I know that sounds strong, but you can make an hour film for YouTube on the dreadful starts Mark in his Bull has made over the years.....


Thanks Ben, I don't mind a lecture! I was just seeking some re-assurance that an electronic glitch won't rob a driver of half of his braking capacity. I've read your well informed essay, and you are right, the teams and the FIA wouldn't deliberately introduce a new system that jeopardises driver safety.

Thanks for the info on the back up hydraulic system as well, I didn't bother to read the tech regs, as you are right, they are very convoluted and hard to understand.

Thanks for the wisdom and insight Ben, much appreciated.


>it says that a hydraulic system must be used as a back up to the powered system.

So this sounds like a normal braking system where the hydraulic pressure (provided by the driver) is what powers all the brakes, and the new system modulates that pressure under electronic control, exactly the way that ABS does in your road car. Electronics fail, you still get the brakes.

Of course if ERS fails they're going to be effectively out of the race, so the fallback system might not be needed for much more than getting back to the pits.


I'm sure they'll have a backup wire.

After all, this is F1 where people think ahead 🙂


Random, when you said F1 people think ahead you were right - apart from a certain team from Milton Keynes and a certain Parisian engine manufacturer and a certain designer called Adrian..........


I've posted this theory on previous forums before, but I believe every so often Adrian produces a right stinker by being a bit too clever and getting waylaid in a technical mire. Good examples are the 1989 Leyton House, the 1994 Frank FW16 (OK did win the constructors, but until late season no match for Michael/Benny), and the truly awful 2004 Macca MP4-19 (the mid season MP4-19B was to all extents and purposes a brand new car, and not before time). If there is a 4 in the year - 1994, 2004 and now 2014 Adrian seems to produce a lemon......just a theory!


They were thinking ahead:

Renault was thinking they could build a reliable engine provided it wasn't constricted too much, Adrian thought that Renault were building an engine that could handle his tight packaging without overheating, and Cristian was thinking that they both knew what the other one was thinking.

I honestly can't understand how it all went wrong 🙁


Yes, I've just read Ben's essay below and it is mandated that the teams have a hydraulic back up, in case the electric sensors fail.


The part of the ERS called the MGU-K which is geared to the front of the crankshaft is controlled by the driver by means of the throttle and brake pedals, when the driver presses the throttle pedal the MGU-K will supply additional power to the crankshaft (no push button), when the driver presses the brake pedal the MGU-K will charge the ES/batteries (harvesting), when the driver goes on the brakes the engine braking is part of the braking effort, to the engine braking effort must now be added that of the now much more powerful (harvesting) MGU-K. The energy harvested through the rear axle has now been doubled, this means the rear brake duty will be far lower, the hydraulic system is still there, when the driver presses the brake pedal the system manages the rear brake hydraulic circuit and the harvesting effect together so that the rear braking effort matches the front to rear brake balance better.


KERS was seen as analogue while ERS is now seen as digital, KERS provided ex BHP for a set time that the driver pressed a button on the steering wheel, ERS will be linked and mapped to the position of the throttle pedal meaning that the way in which power is harnessed can be altered in a 3 dimensional context.

The driver will have a ERS map available to adjust on the steering wheel but will not have the freedom to access it, the ERS settings will allow for various combinations of power against time, such as 161 hp for 33.3 seconds per lap, 80.5 hp for 66.6 seconds per lap, 40.25 hp for 133.2 seconds per lap and so on.


So around Red Bull Ring there would be a way to use ERS for nearly a whole lap?


Drivers must be "alone and unaided" yet :

We never see tyre smoke off the startline which implies that they have some sort of aid in regard to traction.

Engineers decide whether the driver should go faster or slower so clearly they have an aid in regard to strategy and engine preservation etc.

This year, engineers will tell them how fast or slow they need to go to preserve fuel for the remaining laps so, once again, the driver is aided.

And they will also have the braking aid too.

Just remove the drivers and let the guys in the puts control the whole thing. Will save a lot of money overall.


You've got a good point. but what you've observed here (the no smoke starts) is called engineering optimisation.

The drivers do not floored the trottle at the start. Instead, he pushed it to a prescribed level (as instructed by engineers) and release the 1st clutch at the start. That release engages the clutch partially and the amount of partial engagement is prescribed by the engineers.

So the start is highly optimised but not done automatically. It has to be executed by the driver. In other words, the driver is the traction control system.

This means the driver is not aided during the execution of the start.

If you have a manual car, you can also do a DIY launch control start. But you have to try out many different levels of trottle and clutch before you get it right. If you do get it right, the start will be swift and no tire smoke. LOL!!


The ECU knows exactly how quickly the engine revs can rise in each gear when the wheels are not spinning. This gives a very effective form of traction control without needing any input from the rear wheels.

The downside of this form of traction control is when starting. It is only when moving off at the start or from a pitstop that this doesn't work. At practically every other point of wheelspin one wheel breaks traction before the other - due to the differing loads when cornering. When moving off the loading on the rear wheels is identical so there is no input from the Diff settings and the ECU will not back off the throttle if the wheel spin matches the theoretical maximum rate of acceleration... as it doesn't know that the front wheels are turning much more slowly.


Most of what you just said was complete fiction


I thought the rate of engine rev rise, in other words, the torque map is determined using burn outs.

Which is why they have a prescribed burn outs before the start to tune the torque map to that section of the track.


I wonder if we will ever see a racing series where the cars are completely automated. The technology exists to allow cars to drive on the roads without a driver, so it can't be that hard to adapt it to racing rather than driving safely.

I wonder if we will ever see a completely automated racing series? That would be a 100% engineering contest.


Would anybody want to watch? You almost may as well run a computer simulation and announce a winner.


Whether or not people will watch it is debatable.

But running a computer sim will not be enough to determine the winner as computer sims are too idealised/over-simplified.

Have you seen the DARPA's robot 4x4 race? It is incredibly fascinating for technical savvy people but definitely not for people with average intelligence.


"We never see tyre smoke off the startline which implies that they have some sort of aid in regard to traction."

I'm inclined to think that's more just down to the different era of F1, i.e. the Pirelli era. That, and the teams are all better at what they do. It's not going to be good for the Pirellis to spin them up like a lunatic, plus however many years on, F1 is now a delicate science. They know what the optimum amount of slip is for maximum traction, and the optimum doesn't involve creating huge plumes of tyre smoke.

On board footage of the starts quite often shows that if they're running any traction control, it's doing a fairly poor job of it. The only car I wonder about is the Ferrari, with it's near flawless starts week in week out. But if there was anything potentially dodgy there, I suspect the other teams would be making a big fuss about it.

Alberto Martínez

Thanks James,

Finally an article about this subject.

I´ve been surfing the web for some days looking for a technical analysis of this new complex system and the information about it was scarce, so I was looking forward to reading something with a deep analysis and you have done it.

That´s why your blog is a must for any F1 fan. Congratulations!


Well, Im just thinking that there will how ever be the front brakes that will be open for locking or if the balance iss too much in the front then you will be losing efficiency for braking. So its a semi abs kind of system. The chips cant regulate the balance I presume...


Clever stuff. Good to see an explanation - thanks.



It sounds like the front brakes are as they were last year. My understanding is that most of the braking is achieved at the front so it should still be possible for the driver to lock up the front and lose grip unless great skill is used. Also interesting that in event of an electrical failure the master cylinder will still provide the force necessary to stop the car. Wasn't there a team last year that had found a way to link the front and rear brakes? If that we're the case you would in effect have ABS and electrical aided braking on all four wheels. Perhaps it's not allowed this year?


Will teams hide traction control within this system? For example, when accelerating the driver could touch the brake pedal which could send excessive power to the KERS rather than spin up the rear wheels.

Perhaps Red Bull where already using KERS friction for this purpose last year.


There is little point in trying to hide the traction control they have used ever since they have had programmable ECUs.

The ECU knows exactly how quickly the revs can rise in every gear. The rear diffs are set up very precisely for every track to prevent one wheel turning more guickly than a corner needs. Added to that a wheel spin means that the revs rise more quickly than is possible without a wheel losing grip... and so the ECU will back off regardless of where the driver's right foot is.


The standard ECU manufactured by McLaren and used by all teams is not allowed to do this. Traction control is banned.


think again - and read what I wrote.

It is not traction control as used by road cars where they use the ABS sensors on each wheel. With the ability to control the rear diff and understand the characteristics of the of engine they have what is effectively traction control by another name.

These guys are clever enough to work around such a simplistic rule.

as "no traction control" just like they bend every rule as far as they can.


What's the fuss about drivers using throttle and break at the same time? Is it some kind of revelation for engineers watching telemetry? Cause drivers learn to do it when they 5 in go-karts.

Kimi, you using break out of corner 4.

I know.


This doesn't tell us anything beyond the obvious. Is the computer controlling the front/rear balance now, or do they still have a lever for that? Does it adjust the right/left braking balance along with the differential control it's doing at the same time, or must the left & right brakes be applying equal force? What if the braking is during a turn -- the ERS will be applying force transmitted through the differential, so it will be braking the outer & inner wheels differently; so unless the electronic friction brakes can do the same, they can't fully balance the ERS. But if the friction brakes are doing left/right differential, how's that legal whereas the old McLaren 3rd brake pedal was banned (for braking just one side of the car) ? Wish the article had gone into more depth, not just spoon-fed us the obvious.


I would be interested to know: Is brake by wire "quicker" or "slower" to react, compared to a mechanical brake system? Also, I wonder if it will improve reliability of the brakes (in their own right, apart from the tie in to ERS)? It seems that electrical versus mechanical is a big choice engineers face. Take the DRS - most teams operate it with hydraulics because it will open the wing more quickly than an electrical system. Albeit an electrical system 'should' be more reliable. I'll look forward to see how this plays out.


ABS is not allowed in F1, The newly introduced brake-by-wire on the rear wheels only system is an addition to the master cylinder hydraulic pressure system which operates on all four wheels, The brake-by-wire on the rear wheels only system regulates the hydraulic line pressure to the rear wheels to give a much better front to rear brake balance (bias) which used to be selected/adjusted by the driver.

Adrian Newey Jnr

James - it would be interesting to hear from someone like Prof Gillan how he thinks drivers could use this system. For example, I think I remember Button having a different brake set up to Hamilton a few years ago because he preferred the "feel" of one brake manufacturer's set up over another. Therefore how the "feel" translates into electronics would be interesting to hear.

Perhaps this will again benefit the new drivers relative to the older ones, much like Vettel reportedly being able to learn how to drive the exhaust blown difuser and Webber not being able to adapt his style.


Mr moderator, why does technical and non offensive posts to your site disappears from on your pages?


What are you referring to? - Mod


A couple of points to clear up. As I understand it brake by wire does not replace hydraulics with electronics. It does however remove the mechanical linkage between the pedal and servo. Instead a 'demand' signal is generated electronically, sent to a processing unit. This unit gathers parameters from the rest of the drivetrain and ers system and after considering an appropriate amount of force (not exceeding any limits in the system) sends a signal to the servo to apply X amount of force to the brakes. What will have been incorporated is some form of 'feel', an artificial way of conveying the sense of force on the pedal. The simplest device would be a spring however I'm sure its a lot more complicated. In aviation these sorts of fly-by-wire systems always have a minimum of dual redundancy (2 independent data channels) for safety and I'm sure these units would be the same. This system could definitely be adjusted to provide an element of ABS.


Thank you for sharing!


A couple of points to clear up. I work in the aviation industry and as I understand it brake by wire does not replace hydraulics with electronics. It does however remove the mechanical linkage between the pedal and servo. Instead a 'demand' signal is generated electronically, sent to a processing unit. This unit gathers parameters from the rest of the drivetrain and ers system and after considering an appropriate amount of force (not exceeding any limits in the system) sends a signal to the servo to apply X amount of force to the brakes. What will have been incorporated is some form of 'feel', an artificial way of conveying the sense of force on the pedal. The simplest device would be a spring however I'm sure its a lot more complicated. In aviation these sorts of fly-by-wire systems always have a minimum of dual redundancy (2 independent data channels) for safety and I'm sure these units would be the same. This system could definitely be adjusted to provide an element of ABS.


Have you seen a film called ENDER S GAME ? I think this is the way F1 is going ,we will see 12 years old kids racing because they are the only ones capable of mastering the "cars". You really think the down to earth street car will become more complex to drive rather than more simpler ?I think Bernie will end up with a bunch of computer game crazy lads wetching F1,but maybe that is what he wants .Did anybody follow the 24 h Daytona race,good old racing alternative.


Watching F1 races on national TV (as we don't have any retired F1 driver) I saw many times "civilian" sport commentators mislead about who was the real leader of the moment as tire management necessities,rather than pilot ability /car performance dictated the pace in the remaining laps.

This year even experienced BBC commentators will watch in total suspense if the driver in front will not slow down or even stop before the finish line out of fuel.

As for the "Drivers must be “alone and unaided” yet :" of Craig (above), they already had power steering, throtle aid (at start) mnow they have brake "tutor", maybe the day when F1 will be a 100% secure sport as driver will drive from the pit wall is not very far.


And add a little bit of data from the actuator on the steering rack and hey-presto, inside wheel braking as per the 2006 Macca

If the ERS not fixed and directly related to the pressure applied to the brake pedal then I don't see how this is not a driver aid - Just stamp on the pedal and let the throttle position algorythmn work out where you are on the circuit, how far to the corner and therefore the best option for energy recovery and speed retardation.


Wonder how long this formula will last. All these regulation changes must cost millions.

If you'ld ask me, it would be good old V10 all the way again.


ABS is not allowed in F1 but than many a thing was not allowed but ways have been found by teams of how to circumnavigate the FIA wording that forbid driver aids, one such example was last year one a team was mimicking traction control out of a corner by the use of the MGU-K harvesting under part throttle.

The FIA can keep things under control to any which level they wish because they are able to access the ECU mapping.


Why do the regs restrict the system to the rear? Regular cars expend about 70% of braking force through the front wheels. Maybe it's less for high downforce cars but momentum will always push the weight of the car forwards.

Did they know it would reduce stability and control and therefore ban ERS to the front wheels? Is it on its way with the next regs?

Or is ERS a complete con- just converting un-used power going to the driven wheels to charge the system?

Does the system only harvest power from the wheels that are driven when the ERS boost is used?

Surely applying ERS to the rears only, makes it a token effort. If they are serious about efficiency, all wheels will be used and that will drag F1 into the realms of All Wheel Drive.


"Does the system only harvest power from the wheels that are driven when the ERS boost is used?"

Please think about that a bit more - or have you invented the impossible perpetual motion engine?

You cannot add power in order to take it back out at the same time! They call them Motor Generator Units for a reason... they can either consume energy (taking electrical power from the batteries) or generate power (charging the batteries) it is one or the other - there is no way it can do both at the same time!


There is also the other dynamic which is sending additional power from the MGU H to the MGU K directly

Engineers say that there is a lot in that


That's the interesting bit, and the bit that's relevant to road cars. You could do away with the storage element (i.e. the heavy batteries) and still get more power and economy from having MGU-H directly powering a motor on the drive train.

I want a road car with that.


The braking system with this electronic design will be exploited by Being able to deliver extremely light braking forces to just the rear wheels. This will allow more consistent power delivery, reducing wheel spin by essentially acting as a clutch. With rear bias set on the brakes, drivers will essentially be using the first 2-3 cm of braking pressure purely as traction control on the gear shifts. They won't need nearly as much overall breaking power during the races anyway as there will be lots of lift and coast rather than late braking. For fuel saving. Alongside engines, those with the best braking system will be in with a real advantage this year. I think Ferrari looked to already have something like this in place which would explain the smoother torque


The regulations as are stipulate (two rear driven wheels), also an ERS MGU-K that can augment X-power to that produced by the IC engine, all this to the driven wheels, also stipulates that this MGU-K can harvest X-power back to the ES/batteries, for that reason the MGU-K is geared to the front of the IC engine crankshaft.

The more a wheel is loaded the more the braking effort (force) that can be applied before said wheel will lock-up, so the more aero down-force the more braking effort (force) that can be used.

Because of the MGU-K harvesting which adds a great level of engine braking to that of the IC engine it is at the rear wheels were the most braking effort (force) changes are taking place and ditto the most difficult to control now beyond the capability of the front/rear brake balance (bias) adjuster as used by the driver.


Is it defined by the rules to install ERS generator on the rear axle only?

and the reason? most of kinetic energy releases on the front axle..


And when the ERS boost is used the ERS (MGU-K) is augmenting X-power to that of the IC engine, Harvesting is done only when the brakes are used.


No offence intended but some real incredible comments on here about F1 racing matters by some that follows F1.

“The car must only have four wheels mounted externally of the bodywork, with only the front two steered and only the back two driven”.

No energy is released TO or harvested from (on) the front axle as the front wheels are not connected to the power source of the car.


6th 2014 at 2.35 pm, James Allen reply. “What are you referring to” –Mod.

Another post to this page having gone missing, right here today.




James, this topic is so interesting. Can the MGU-K be used under acceleration to maximize traction coming out of the corner? Similarly also to maintain balance at full cornering? This area seems so ripe for fiddling.



That RBR was mimicking traction control out of corners last year was talked about a lot, the cat was out of the bag in Canada when tyre marks were observed as the car exited the corners plus the strange noise from the engine, it was clear that they were using the MGU-K in harvesting mode at part throttle, but this doesn’t mean they were breaking any rules because while harvesting is supposed to take place under braking nothing prevented them of using the brake pedal on exiting a corner and under throttle, no matter how light.


As this year the cars will be much more traction limited as a result of the new power unite a much bigger effort will be made to gain some advantage in this aria (traction out of corners) more so when power output/outright speed/flat-out racing have all been limited by the fuel flow and fuel weight for a race as mandated by the rules.

The state of play will be totally different this year, one of the most important things this year and without which a driver has very little chance not only of not winning a race but even that of finishing a race is radio contact between car and pits.


Does this mean maintains rear brake temps will be harder since there less demand from them? Not sure if some asked this already.


The rear brake calliper will be much smaller this year.

The drivers will have to adapt to the feel of the new system (brake feel).


And ditto exactly like last time as soon as I press submit that missing post pops-up again.

Are you reading JAMES?


Yes we are reading. Checking it out

Funny thing is no-one else is reporting that


In the hope of being of some help to you I will explain.

When I submit the post can be seen on the page ok, if I go off the site on returning to the site and to that page the post is gone, if I post again that disappeared post will pop-up more often than not but not always.


"This makes it acceptable for the driver and doesn’t destabilise the car with a sudden balance shift. A lot of the lap time in modern F1 comes from stable braking."

Rather sad. In the old days, a lot of passing was really one driver being able to brake better than another. A great driver was the one who had that intelligent foot, who could modulate that brake pedal. With the advent of carbon brake rotors and lithium, then beryllium calipers, braking has become less about smart feet, and more about the ability to mash the pedal at the very last second possible.

I'd rather they keep mechanical hydraulic braking.


Hi James, someone mentioned earlier about turning the car using the brakes. Did you find out any further?

Also, one of the critical settings for modern F1 cars has been engine braking or more specifically how much engine over run was used to offset the engine braking effect (or off throttle blowing of diffusers for e.g). How do the new systems incorporate this effect? As they used to consume fuel (by supplying a throttle %)do the new systems consume electrical power to prevent the rear wheels locking?

Having the right engine brake setting is critical for stable braking and off throttle/coast balance, especially in faster corners like Maggots/Becketts where the rear wheels dragging slightly can help keep the nose tucked in.


If this new system is stop rear wheel lock up..What happens in those situations where a driver needs to lock up all 4 wheels to wipe off speed ie before collisions etc., won't this new system remove that.and increase impact speed/force


Really thrilled to know about the working of the brake wire. Good and good information.

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