Will slicks put brakes under more stress?

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A tougher time for brakes in 2009?

One aspect of the 2009 rules I’m trying to get my ahead is how the return to slick tyres and the introduction of KERS might affect brakes.

If my shaky grasp if F1 technology is right, I reckon brakes will have a seriously hard time in 2009. Check my working below.

Slicks means greater peak braking effort

Grooves are gone and tyres are staying the same size. That means each F1 car will have a significant percentage more rubber on the ground, which will allow them to grip better and corner faster.

This suggests to me that when a driver hits the brake pedal he’ll be able to generate greater braking force than he could in 2008. Therefore, the brakes will be under greater stress. And with the technical regulations not allowing for an increase in brake size, drivers will have to take greater care of their discs.

But here’s the bit I’m not sure about: will the accompanying reduction in downforce this year reduce the demand on the brakes by the same amount? I need someone with a technical mind to put me straight on that one.

Top tracks for braking

According to BMW, this is how the circuits rank for brake wear – and the ones at the top of the list could pose the biggest problems for drivers:

Singapore – very high
Monte-Carlo – high
Nurburgring – high
Albert Park Melbourne – high
Bahrain International Circuit – high
Hungaroring – high
Monza – high
Suzuka – high
Shanghai International Circuit – medium
Circuito Urbano Valencia – medium
Silverstone – low
Sepang International Circuit – low
Circuit de Catalunya – low
Istanbul – low
Spa-Francorchamps – low
Interlagos – low

What about KERS?

An added complication from the point of view of braking is how KERS could affect it.

F1’s Kinetic Energy Recovery Systems are designed to work by extracting energy from braking effort – but will it have any effect on braking performance? How is the energy transmitted from the brakes to the KERS?

Share your thoughts on brakes below…

Author information

Keith Collantine
Lifelong motor sport fan Keith set up RaceFans in 2005 - when it was originally called F1 Fanatic. Having previously worked as a motoring...

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33 comments on “Will slicks put brakes under more stress?”

  1. Hasn’t F1 always been a sport with extremely low tolerances being set everywhere? I expect the teams to work around this with minimum effort. It’s just that they’ll have to reconfigure a variable or two and within a few weeks, they’ll be braking harder than what they used to, with no worse brakes.

  2. This suggests to me that when a driver hits the brake pedal he’ll be able to generate greater braking force than he could in 2008. Therefore, the brakes will be under greater stress.

    Greater stress indeed, but presumably the brakes are used for less time whilst applying force? The net effect should be almost the same… I think..?

    1. don’t think driver will use brakes for less time because the forces are higher…

      Slickes means shorter braking distance with the same amout of brake forces, but in shorter time.

      So the stress is higher, logically, because less time means more usage for the same result…

  3. Interesting point, Keith. What about the cooling effect of KERS, however? Since KERS is drawing off heat from the brakes to store as electrical or rotational energy, it will be much more difficult to get the brakes up to their working temperature. Don’t forget that F1 brakes are almost useless until the disc becomes hot. Even if the engineers have already thought of this, they will still have to re-think present cooling systems, making them less efficient so that the brakes will run hot enough. And that means more unnecessary complication and expense – wonderful, isn’t it?

    1. Or they can simply monitor the brake temperatures, and increase/decrease the amount of KERS braking to compensate.

      One nice thing about having a secondary braking mechanism is that, were the brake discs to fail, an emergency measure of setting KERS braking to maximum could hopefully partly compensate, allowing the driver to limp back to the pits

  4. I agree about the additional grip from the tyres could pose a problem, but I’m not sure about the ranking of the circuits – places like Montreal and Hockenheim used to be bad, but Monaco is pretty easy on the brakes.

    1. Monaco is pretty easy on the brakes

      Monaco is very tough because of the high number of times per lap the brakes are used and the very small gaps in between corners, which don’t allow the brakes very much time to cool.

      Unlike, for example, Spa or Silverstone which both have long straights allowing plenty of opportunity for air to flow through the brake ducts.

    2. Taking Tim’s point and Clive’s point above, it could probably mean that places like Spa, Silverstone, Fuji would actually cause problems for problem; due to excessive cooling.

      Whereas; in Monte Carlo, thanks to the inefficient cooling system, and less time required to brake ( as rightly said by John H above ), probably the brakes will remain heated up for too long and will also face higher peak force.

      So to sum it up; on all tracks alike; brakes are going to face the brunt.

  5. It´s a good observation from Keith. My concern is that the extra grip makes overtaking even more difficult in the braking area.
    Sorry to sound like a scratched record, but if we had steel brakes with a limit on disk size, the braking distances could be say 50% longer and maybe then we had a 50% better chance of overtaking while braking.
    This would be fantastic for the sport and might constitute the cheapest and easiest way to improve overtaking

    1. I’ve said this for a few years now that steel brakes would be a cheap way of improving the overtaking question. Very few formula use carbon brakes, they band it in Champ/Indycars years ago. Like you say if you increase the braking zone you must increase the chances of overtaking.

    2. After half the season has been, its clear that the braking distances are even shorter than last year and overtking ia no easier!!! Increase the braking distances so they are not braking almost in the corner!!! This will lead to more chances of overtaking

  6. if my tech knowledge is any good, i would imagine that the brakes will take roughly the same wear on the majority of circuits, except the slower ones.

    if i’m right – the total level of grip is the sum of the mechanical and aero grip. the increased mechanical (tyre) grip will be cancelled out by the reduced aero grip. so unless you are travelling particularly slowly where the aero is responsible for only a small percentage of the total grip i can’t see that you would be able to apply any more brake pressure than last year without locking up.

    monaco should be the real test.

  7. KERS works much like the engine braking – an opposing force which is applied to the powertrain, not the brake disks themselves. Hence KERS should make brakes life easier. So the KERS-equipped cars will have another advantage.

  8. …where is a mechanical engineer when we need one?

    Here is another spanner to toss into the mix. The brakes have a certain capacity of force they are capable of transmitting to the tires (which won’t change unless the brake regulations change). The tires have a certain amount of grip they are capable of transmitting to the road. The real question is, as Keith has mentioned, will the tire’s grip capacity exceed the brakes capacity?

    Certainly the teams should be able to answer this question quite easily, at least in theory. And, of course the KERS, to operate correctly, must assist the brakes in reducing the rolling inertia of the car as it slows.

    Sorry, not really adding any info to the mix, just questions.

  9. To add to the confusion,

    Due to the change in aerodynamic and mechanical grips; cars are going to be slower in faster corners; and faster in slower corners in 2009. Thus effectively; reducing the amount of braking required. So; I guess although the brakes will face more stress; the demand for brakes itself will go down.

    I am a 4th year mechanical engineering STUDENT; so I don’t know much :). Thus; I will still ask questions than giving answers.

    1. I’m a 3rd year Mech Eng with Aeronautics student and whilst I was reading the story I came to the same conclusion as sumedh – so I guess we either both know a bit or equally little!

      I don’t think the brakes will be affected by the reduction in downforce. As the car slows the effect of the wings is reduced as is their ability to produce downforce – thus at slower speeds aero downfoce isnt important and, due to the higher mechanical grip in slower corners (where more braking is needed!) the slicks should ease the needs for braking as they will allow more speed to be carried from entry to apex.

      Well, thats my hypothesis anyways… don’t quote me on that!

  10. Is there more than one available brake compound? In other words can they produce a harder or softer brakes?

    Anyone have the rule book on what is/isn’t allowed?

    @sumedh – I disagree, I think the need for braking will go up based on that logic. The cars should be just as fast on the straights but require more braking and slower speeds in the corner. Assuming there is no “Kers Braking” used.

    1. Is there more than one available brake compound? In other words can they produce a harder or softer brakes?

      Yes. Brakes aren’t standard items (yet) so teams can pick and choose different specifications of brake pads, discs, ducts, etc to suit the circuit.

      Montreal always required the most robust specification as one of (if not the) toughest track for braking. However, there’s no point using those at every track as they tend to be bigger and therefore heavier.

  11. I’m a graduate mechanical engineer and have done FSAE for quite sometime. I’m not quite convinced that braking will be an issue. I believe that due to the reduced downforce…managing your tyres will be even more crucial since there is a larger chance that you can lock up the wheels under heavy braking and leave flat spots on the tires and thus create vibrations which will require you to come into the pits for a new set. Given the fact that they now runs slicks and their contact patch is slighty larger but with less downforce..at the end of a straight away, they can and will lock up more often.

    Now, if you if think about last year..more downforce and grooved tires. You’d have a similar senario only backwards, less tyre but 50%(so they say) more downforce. So, the difference in braking between now and then is minimal. Like it was then and is now ….Tyres Tyres Tyres…thats the key.

  12. bit off topic but has anyone noticed that the test pictures, particularly the ferrari, seem to show the car leaning into the corner? You can only see it from the front as you look along the front wing. Ive not seen an f1 car lean since the early 80’s. whys it happening? Is it just the enormity of the front wing showing up what was previously undetectable or are they running softer suspension for some devious rule breaking advantage?

  13. A friend of mine and I have been talking about the subject some more and we both believe that with the switch to slicks, the cars will have more mechanical grip/traction because of the larger contact patch. With the downforce being reduced, the important quality to have is aero balance so the car doesn’t pitch or yaw under braking, which is what antonyb was pointing out. The increased grip and reduced downforce should/could balance each other out. As KERS draws energy away from the brakes, the brakes may see less load. In the end, we don’t think brakes will be an issue this season.

  14. * Braking deceleration.

    This, like cornering is downforce & mechanical
    grip limited. Ignoring second order effects like
    car balance under cornering vs. braking, you can
    pretty much just take the statements about cornering
    and interpret for braking.

    During high speed braking, it’s downforce limited,
    and the reduction in DF will more than outweigh the
    gain from slicks. This is the same as the initial
    reports that the new cars are slower in fast corners,
    faster in slow.

    Energy dumped in the brakes is Force x displacement.
    Power dumped is Force x Velocity.

    As the force is greatest at highest velocity, the
    peak rate of heating is surely going to be decreased
    by the new rules.

    I’f bet braking distances are dominated by the high speed end (remember your 60/120/240…. :) ) and long straight to hairpin transitions will likely have quite increased braking distances – more chances to overtake?

    Much of this is clear in various statements in 2007 about Hamilton’s braking technique – v. high initial braking force and accurately backing off as he slows to match the loss of downforce. Not that I have any way to prove how accurate they were, I guess. Now, they’ll have to decrease the initial force, and not back off
    as much as they lose speed.

    * KERS

    Personally the energy recovered from KERS is overemphasized.

    70BHP for few seconds.

    The engine is 700BHP, running pull power
    for half the lap on some circuits. (40-50 seconds).

    Braking deceleration greatly exceeds acceleration.

    Sure, there’s a lot of drag, but I’d bet the energy dumped into the brake system is around 10-100 times the
    KERS recovery.

  15. Initial thoughts are that the braking torque will not be affected so work done by the brakes will be the same.

    However KERS could affect the front/rear brake balance. Klien seemed to think it was ok at the BMW launch. It might become more of a problem when the KERS power increases.

  16. Wings not only produce downforce, but also air resistance, obviously. Braking is the only place where a higher air resistance is a positive thing – cause it helps slowing the car down. Thus, the cars with less downforce have a longer braking distance, which causes brakes to be used for longer periods of time.

  17. Most likely the brakes will receive more ventilation to account for the increased stress. This will probably compensate for the increased wear.

  18. More rubber maybe, but the tyre compounds are somewhat harder than a few years ago (at the height of the tyre war). Less downforce at the rear, but how about at the front? Add KERS, and I’d be surprised if the front brakes are as stressed as they were a few years ago.

  19. mmm yes interesting! I did not know about this rule change of not being allowed to increase brake sizes…

  20. Lets not take that braking distances will be shorter for granted. Yes slicks means more contact patch, but there will be less downforce to help braking.Also we dont know much anything about the tire compound, maybe the compound will be harder so it gives less grip for the same contact patch.

  21. Interesting question. Brakes are there to dissipate kinetic energy. 1/2 mv^2. If cars are faster because of less drag, then more energy to be dissipated. But if grip is better then can corner faster therefore don’t need to lose so much kinetic energy before corner. KERS will assist the brakes (Prius drivers report much lower brake pad wear) but lower aero drag will increase the work the brakes have to do. In any case, driver will want to brake as hard as possible, so will stress brakes to maximum. But can tyres transmit all that braking force? Grip = friction x downforce. Better friction, worse downforce, how does it balance out? Will placement of KERS affect weight transfer under braking to counterbalance loss of downforce?

    My head hurts! But I think the brakes will have an easier life.

  22. I agree w/Mattclinch, only slow circuits should see higher brake wear, and also agree with Ukk in that it’s not through brake heat but rather motion through the drivertrain that KERS does its job
    @ theRoswellite, braking capacity is always higher than grip if they are working correctly, the end result being a lockup, the question being can they consistently do it with slicks throughout a slow race?
    @Mahir C, Everything i’ve heard about the new tyres is that the compound will be softer, in fact someone from bridgestone said so i’m sure, this due to the fact that the structural requirements for grooves no longer apply.
    @martinb, i’m also thinking you won’t always have more straight line speed, i’m thinking of mid to short straights with a previous quick corner that will see lower exit speeds due to less downforce.

    My own question, is KERS capable of discarding energy in an effective way? ie, you can only use 80hp during 6 seconds per lap, but what if you were to need the unit to simply assist your braking a lot more than you are allowed to release the energy through the drive train? I guess the only way would be through heat, some type of big resistance?

  23. I should also note that front brakes will still get no help from KERS at all, and being they are the ones that are more stressed we might see issues on the slower circuits

  24. New to the blog and wanted to say great blog so far and I am looking forward to reading more and posting some comments of my own. Hello to everyone!

  25. Make brakes less effective they should, the longer the braking distances the more of a chance the driver got to out brake the other driver!!!

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