Giorgio Piola's F1 technical analysis
Analysis: Teams split as F1 2017 braking forces go up by 25 percent
Formula 1’s new rules for 2017 may have revolved around aerodynamic and tyre changes – but their impact means that many aspects of the car are going to be pushed to extremes in the season ahead.
One area where the change is going to be really felt is under braking – with torque forces predicted to be around 25 percent higher this year than they were in 2016.
This has meant a jump in the size of the brake discs being used for 2017 – with the maximum thickness going up from 28mm to 32mm. The change can be seen in the image below.
But the changes are not just about stamping harder on the brakes, for the increased car grip coming for 2017 could drastically change the nature of some circuits – and turn what were once easy braking circuits into tough ones.
Furthermore, the complexity of modern braking systems – especially with the way brakes and ducts have been used for tyre temperature management and aerodynamic performance – has meant that teams are divided about how best to approach the campaign ahead.
Why the 25 percent leap?
The increase in brake force is not something you would automatically expect from the way in which F1 cars are getting quicker this year.
For it sounds logical to suggest that a car that goes slower in a straightline and takes corners quicker would actually need less braking – not more.
It would surely only make sense for braking force to go up if the cars were faster on the straights and slower in the corners; so needed to scrub off more speed.
But car dynamics can be quite complicated, and it is the increase in grip this year – through both wider tyres and downforce – that is key here. For it means drivers will be able to brake harder and later.
Brembo's Mauro Piccoli told Motorsport.com: "The level of grip is higher so you can basically transmit more force in a shorter time under braking. That results in the peak of braking torque – and we are predicting a 25 percent jump."
There could be further knock-on consequences too from the faster cars – because now with some corners flat-out, drivers will be arriving at subsequent turns much faster than they were before.
Piccoli explains: "We have seen on the simulation that some corners where cars were slowing down a bit – like in a sequence where you had a first turn and then a second one (such as Turns 2/3 at Silverstone) – the car used to slow down in the first corner so have reduced speed when it entered the second one.
"We are expecting that at some tracks, where the first corner is not too tight, that it will be taken at full throttle, so overall speed entering the second one will be a lot higher than in 2016.
"So what we think is that at some tracks like Silverstone, or Interlagos – the real number of stops is going to decrease but the energy of the stops is going to increase. This is translating as a higher braking torque. What were low duty tracks in 2016 could become heavier in 2017.
"And if you are loading the disk with more energy in a shorter time you have to dissipate the heat more quickly – which is why we need more cooling."
The increase in forces means that the rules around brakes have changed – so that the maximum width of discs goes up to 32mm for this season.
The larger size has meant that there will be greater flexibility for cooling holes, with the number set to increase from the 1200 that Brembo were drilling before to 1500 this year.
"The thicker disc will allow us to have more cooling, as there will be more space for cooling holes," adds Piccoli. "It also allows us to design a stronger fixing to the brake valve, because for 2017 we are predicting a huge increase in the braking torque. So we need a disc that can be designed accordingly to this braking force."
Piccoli expects braking G-forces to exceed 6G this year.
One of the big fears about the 2017 regulations is that, while cars will be more spectacular and faster, the racing may not be any better.
Higher aerodynamic sensitivity may make it more difficult for drivers to follow each other closely, and the shorter braking distances will make things even tougher when it comes to finding a way past your rivals.
But Piccoli suggests that things may not all be bad – and the phenomenon of some corners being heavier on brakes this year because cars are arriving at them much quicker could actually lengthen up some braking zones.
"Certainly some braking distances will be shorter, but we still have to understand if the braking is comparable to before," he said. "If you arrive at a corner having not slowed down the car for an earlier turn, then the second one is becoming heavier. So the speed will be a lot higher than before, and in the end the braking distance could be a lot higher and the power going on the brakes will be higher.
"We have our simulations, but it is hard to make an average value considering all the different tracks. But before making any guess, I think we have to see on the cars. Barcelona [testing] will give us a good indication – and right after the first test we can be more precise."
One interesting aspect that has emerged about brakes ahead of the campaign is that there is not a consensus among teams about the maximum dimension of discs they will run at the rear.
The arrival of Brake-by-Wire systems in 2014, where the kinetic Energy Recovery System helped in slowing the car, meant that rear brake discs and calipers got smaller. The discs shrunk in diameter from 278mm to as low as 268mm – although all Brembo's teams retained the 28mm thickness last year.
For 2017, despite the predicted increase in forces, some teams have elected not to make the jump up to 32mm – feeling that the extra 150 grammes of weight that comes with the larger disc is not worth it.
It was interesting that towards the end of last year, Mercedes ran a lot of brake experiments in free practice sessions with a view to 2017 design.
Piccoli explains: "Right now, we have teams that have decided to go ahead with the 28mm disc, and teams that decided to move to the 32mm at the rear. It is certainly related to the brakes and braking performance, but that is not the only reason.
"In the past years, brakes have also been used to control the temperature of the tyres, so I think these two choices lead also a different way of controlling the temperature on the rear. We will see.
"It is now a choice that has been done in terms of caliper design. Anyone that decided to go to the 32mm can move down to the 28mm if needed, you can always run a thinner disc. But it will be more difficult for whoever decided to stay on a 28mm to move to a 32mm without changing the caliper."
At the moment, a small majority have opted to stay with the 28mm [the current split is 60/40] – and the answer about which direction is the best may only come once testing gets underway and teams better understand the 2017 Pirelli tyres.
"We clearly have to understand what will be the real load on the brakes, and what will be the real need from the driver. The driver is not thinking about braking torque or pressure in the brake line – he only cares about pedal travel versus retardation. His expectation is of how the car slows down compared to a certain pedal position or certain force on the pedal.
"We now have to understand with these changes, what is the load compared to the feeling of the driver? Then we can adjust the brake system accordingly.
"We have done a lot of work in simulation, but every team has its own brake system, and we can see different approaches in brake systems for this year. We need to see who has got it right."
Barcelona testing then will not just be able how well the new generation of cars go. There is going to be a lot of intrigue about how well they stop too.
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