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13 May 2013

The Spanish GP held at the Circuit de Catalunya has for years been a forgone conclusion, rock up on a Saturday, duke it out for pole position and you're guaranteed to take victory on the Sunday. This year that changed and for the first time in years I didn't find myself drifting off in front of the box a third of the way through the race. You will all know I am both a fan of strategy and a defender of Pirelli but perhaps what isn't clear is why the GP became a four stopper. I would also like to say that although Social Media has led to my own rapid rise it may also be the reason why we are seeing Pirelli take the brunt of the criticism this year. If I may borrow a line from the film Inception:

'An idea is like a virus. Resilient. Highly contagious. And even the smallest seed of an idea can grow. It can grow to define or destroy you.'

A symbiotic relationship arose during last season whereby the mainstream broadcast and journalistic media used Social Media to interact with the fans in order to understand their needs and listen to their thoughts. Formula One though, to my eyes is still behind the curve in terms of Social Media and so a protracted view can rear up. Armed with these views and the wantant need to be both relevant and portray what they feel is the view of the many, broadcasters and journalists have been critical of the tyres. The teams have of course also seen the widesweeping effects of Social Media and the manipulation of the mainstream media as a way of changing the minds of the fans to suit their agenda. Think about when one team finds an aerodynamic advantage that others haven't, their first thoughts are can we replicate it? If we can't replicate it, can we get it banned? With life being made difficult for the teams by the 2013 Pirelli's it seems some are now going for the latter....

So when we look at the facts are these views justifiable? Firstly we must understand that FOM/FIA conducted a survey several years ago in order to get an idea of the general perception of the sport. One of the key area's that was highlighted as an issue to people and the key reason people didn't necessarily watch the sport was the lack of overtaking. A decision was made to rectify this and in 2009 the sport went through regulation changes to try and solve the problem of overtaking. Part of these changes involved a change from Grooved Tyres to the Slick tyres we have now. The supplier at the time: Bridgestone had already furnished us with a two compound choices from 2007 onwards but unlike the static compounds we have at the moment Bridgestone would alter their Hard and Soft compounds tailoring them for each track. When Bridgestone were asked to supply the Slick tyres in 2009 the idea was to return an element of mechanical grip back to the sport which had been robbed by the grooved tyres however the Hard and Soft compounds continued to be tailored for each event. Bridgestone always felt that their inclusion in the sport needed to show some road relevance and with the introduction of slicks they pulled out of the sport at the end of 2010.
Enter Pirelli, their brief from the FIA was simple produce a tyre that mixes strategy and encourages drivers to overtake. Using Montreal 2010 as the benchmark the FIA had realised that engineering a challenge for the teams could once again produce close racing.

But why are we seeing such a difference this season over previous years? Pirelli were criticized during 2012 as their tyres were often seen to be the differentiator and so they set about changing their 2013 lineup in order to alleviate some of these grievances. The 2012 tyre tended to wear on the shoulder of the tyre and so even though the tyre still had grip it wasn't available to the driver as it was on a section of the tyre unavailable to him. The new construction features a much softer Sidewall allowing the platform of the tyre to stay in contact with the track, enlarging the contact patch. In line with this the tread platform was beefed up, otherwise it would wrinkle under load leading to a non-uniform level of wear. The 2012 construction also lead to tyre warming issues as the whole surface of the tyre wasn't being aggravated enough and with the stiffer Sidewall energy wasn't being pumped into the tyre.

Pirelli also made changes to the compounds lowering the ranges so they are the equivalent of the lower compound of last seasons. This meant the 2013 Hard tyre was equal to the 2012 Medium, 2013 Medium = 2012 Soft, 2013 Soft = 2012 Super Soft and an all new Super Soft compound. This was done in order to once again challenge the teams as toward the end of 2012 the teams had resolved their issues with the degradation of the tyre.

So why the dramatic difference when all of the above should lead to more mechanical grip available to the driver?

The area that commentators and journalists alike aren't willing or able to talk about: The aerodynamic influence of tyre dynamics. I have talked above about the softening of the Sidewall with these tyres so let us now look at how this impacts the aerodynamics of the car.

At the front of the car the Tyre's profile is one of the crucial elements in shaping the airflow over the rest of the car. With the tyre deforming much more dynamically over the course of a lap it has therefore become even more crucial for the Front Wing to manage the direction airflow is deflected around the tyre.

Airflow going inbound of the wheel is managed further downstream by Turning Vanes, the Splitter, bargeboards, Sidepod etc and so changes in these area's may have already been implemented or be included in the current program of design decisions.

Airflow directed around the outside of the Front Wheel tends to migrate back toward the floor of the car impacting on a key area to which the teams extract performance. The tyre's dynamic changes therefore make the task much more difficult to manage and we find most of the team's are adding 'Tyre Squirt' slots ahead of the rear wheels as an additional method with which to control the problem and it's ongoing effects into the crucial area between the rear wheel and Diffusers edge that teams aim their exhaust plume.


'Tyre' Squirt is a problem faced by an open wheel car but moreover those using the Diffuser as a means of creating more downforce. 'Tyre Squirt' is the airflow that is discharged by the rotation of the rear tyres and is sent laterally into the Diffuser, this is a problem that the teams faced more with the banning of Exhaust Blown Diffusers (EBD) and Off Throttle Blowing (OTB) is that of 'Tyre Squirt'.

The drawing above shows the implications of 'Tyre Squirt' dependent on the aerodynamic influences of the exhaust. (Yellow airflow is air passing around the Sidepod, Blue as the Diffuser's airflow underneath the car and Red as the Exhaust Plume). As we can see in the left hand picture when the exhaust has no influence over the airflow the air received by the tyre is pushed laterally below the floor reducing the Diffuser's effect. The middle picture depicts the era from 2010/11 where teams placed the exhaust on the floor of the car directly in the path of the gap between the wheel and Diffusers edge. This had the effect of cancelling out 'Tyre Squirt' with the airflow coming around the Sidepod instead pushed above the floor into the Coke Bottle region 'Sealing the Diffuser'. This is all well and good if you have a consistent flow in the gap but when the driver comes off the throttle the exhaust plume dissipates. In 2011 the teams used Off Throttle Blowing in combination with EBD and so when the driver came off the throttle the exhaust plume continued to be fed into the gap between the tyre and the floor 'Sealing the Diffuser' even when the car was going through the corners.
The FIA did there level best to stop this practice when they introduced new rules for 2012, determining the locality and orientation of the exhaust whilst preventing the teams from using as much OTB through engine mapping restrictions.
The teams however now knew the use of EBD was a massive performance differentiator and we ended up with the 'Coanda' Exhaust, this method is not as full proof as EBD as the orientation of the exhaust channel and throttle position will give a different aerodynamic effect but it still goes some way to gaining a large advantage.

So come on then get to it, why does this effect the tyres? Well, lets let these two worlds collide...

The 2013 tyres by virtue of their Sidewall construction move dynamically throughout the course of the braking and turning motions. At the rear of the car their movement is in contrast to the exhaust plumes influence between the tyre and Diffuser's edge, reducing the downforce by virtue of more 'Tyre Squirt' impinging on the Diffuser. Perhaps even more critical though is this causes a dynamic change of ride height which also leads to a change in Diffuser height thereby also dynamically altering it's ability to produce a consistent level of downforce in the corners.

This aerodynamic head scratcher is the principle reason we see the likes of McLaren, Williams and Sauber struggling as they failed to foresee the influence the tyre dynamics could have on downforce extraction.

So how can this aerodynamic problem be causing a degradation issue? Lateral load / Slip Angle: As the tyre deforms and causes a loss of downforce the tyre slides generating heat and therefore losing grip before once again gripping when enough force is present. When talking about Slip Angle we must also refer to Cornering Force this is the symbiotic relationship between the angle of the tyre and the force exerted on it which produces the grip. More force should = a higher slip angle but at some point the force exerted can overcome the properties of the tyre as this video below demonstrates:



So as we can see the problem is not the fact that teams cannot produce enough downforce, it's that they cannot provide a consistent amount in order to increase the cornering force.

Moving back to Barcelona I have a few things to make points on, firstly lets think of last years compound choices: Hard and Soft Tyres, what are this years equivalent? Hard and Medium (With the Hard being altered back to a specification akin to 2012's compound before Barcelona) So this rules out the influence of the compounds in this years race being a 4 stopper. The race was completed in 1:39:09.145 by Pastor Maldonado in 2012 whilst Fernando Alonso completed the race in 1:39:16.596 a difference of 7.5 seconds. A pit stop at the Circuit de Catalunya is around 18 seconds and so the 4 stop strategy did not make the race last significantly longer. Kimi Raikonnen finished a further 9.3 seconds down the road completing one less stop than the Spaniard proving that 4 stops and flat out driving was the way to go.

If we look back at 2011 Vettel took the same approach as Alonso with Red Bull realising that 4 stops and a more aggressive driving style was the quickest way around. Red Bull were lauded that day for their strategy approach and so now I'm left wondering why we suddenly feel it necessary to condemn the same strategy.

I know many fans were confused by the nature of this race and I do understand where you are coming from but I missed the first 15 laps (live) and several laps throughout as I was working at the same time but still managed to understand where the strategy was playing out. I'm not drawn by the rumblings of commentator's etc though and instead watch the race for what it is, all the time looking to establish the strategies at play. This perhaps then is one of the failings of the broadcasters, unable to convey the complexities of what's happening on track in a way that makes it easier for the viewer to understand. Another critique of broadcasters is their use of the team radio and the way in which that information is consumed for example, Hamilton was told at one stage that Rosberg was coasting more in turn 3 to save the tyres (Slip Angle, Tyre Wear etc) to which he responded he can't go any slower. The commentary was then led down a path that once again condemned the Tyres rather than the fact Hamilton had a total disregard for the information his engineer was giving him. (Lest we not forget that Hamilton took 4 stops rather than the 3 Rosberg did, losing around 18 seconds of track time and position in the pitlane which had he lifted through 3 might not have been needed.....

If you were confused by the 4 stop strategy vs 3 stop strategy know this, those on 4 stops were driving at a quicker pace than those doing 3 stops something you have asked for the drivers to do ('We don't want drivers driving at 80% of their ability') So what do you want? More stops and quicker lap times or conservative driving and slower, tyre protecting lap times?

The biggest problem is perception, Ferrari had already conceived a 4 stop strategy, whilst the rest of the field were trying to see if they could do 4. By the time this had been realised they had to play catch up and switch themselves to a 4 stopper (Red Bull being one of the biggest culprits of this IMO). As you were not fed this information by your respective broadcaster I understand your quandary but I implore you to dig a little deeper, start out by following a couple of teams throughout the race until you find your able to see the bigger picture. I've been doing this for years, it's not a new phenomenon as we had a similar strategy fight unfold when re-fuelling was in F1.

Armed with this information I hope I have planted a seed that will spread like a virus enabling everyone to realise that Pirelli have actually done what was asked of them and produced a tyre that enables more strategy and increased grip over a shorter time frame. Lets get off their back and look to the teams to engineer a solution as afterall that is who needs to make a change. Formula One has long been a sport that's engineered, whether it be by adding grooves to the tyres to strip you of grip, strategy engineering when the cars needed to be refuelled, managing fragile engines that were built with too much power, faster and faster pitstops or any other permutation that era of racing bought to the table.

Please Pirelli if you're listening don't pander any further to the teams this season, you have done your job now let them do theirs. Once they get a handle on the situation they always get quicker and next year a different type of tyre will be needed to respond to the challenge.

Following on from the news Pirelli will make adjustments to their tyre range for Montreal I wrote this piece http://somersf1.blogspot.co.uk/2013/05/pirelli-to-make-changes-ahead-of.html looking at how these changes could effect the pecking order / season. 
Different Themes
Written by Matthew 'SomersF1' Somerfield

Formula One is a sport that pushes technological boundaries, with the pace of the changes to the cars as swift as the laptimes. This blog looks to keep you upto speed with these alterations.

28 comments:

  1. Thanks for such a detailed write up. I think I agree on the face of what you wrote, but I need to digest it and re-read it to make sure I didn't miss anything!

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  2. "So what do you want? More stops and quicker lap times or conservative driving and slower, tyre protecting lap times?"

    I think one of the big issues is that even when the drivers are going after the more aggressive strategy, they are hardly driving "flat out" (with regard to the potential of the car's performance) because of the fear the tyres might let go. It would be great to see a 2v3 or 3v4 stop strategy where drivers were still blasting around the track w/o adhering to a specific lap time that is slower than what they could otherwise achieve.

    This is Formula 1. The spectators want to see the drivers pushing these cars to the edge. Not pandering to the mercy of "overtaking promoted" tyre degradation.

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    1. Thanks for the feedback Dan, I knew this piece would be controversial as opinion has already formed that Pirelli are in the wrong. I have to ask though by making changes to the construction of the tyre (this is what differs from 2012) are you happy to give a handful of teams an advantage back that perhaps they don't deserve?

      In terms of strategy we won't see the 2v3 or 3v4 stops you're looking for as the teams will always try to engineer a strategy that best suits the faults of their machinery / driver. Lotus could have 4 stopped Kimi for arguments sake but they knew that the optimal way of driving Barcelona for him was through a less aggressive strategy, keeping the tyres in a lower echelon of their temperature range.

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    2. That's the largest issue, IMHO. Pirelli cannot guarantee giving equal terms to everyone, as cars are already built around these tires.
      So, for example, if Williams win the title in 2013 due to tire change it will be totally unfair and absolutely compromised.
      This will be quite simply detrimental to Pirelli's image, and will once again show the real problem - lack of meaningful testing. Paul H. admits that they underestimated the speed teams have found over the winter, but even then Pirelli have an old Renault to test with, which is 4 seconds slower than today's cars.

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    3. regarding teams "not deserving" an advantage i would like to ask you a question:

      imho pirelli did, with its 2013 tyres, favour teams that had issues getting the 2012 tyres to work properly in the first place. that might sound controversal at first, but i highly doubt that teams started work on their 2013 cars after getting a glimps of the prototyp-tyres in november...
      so my conclusion would be that the tyres' working range simply moved away from those being harder on the tyre to those being softer...

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    4. I hear where you are coming from but to me the 2012 tyre had an inherant design flaw. The stiff sidewall and relatively softer tread pattern meant the tyre wore heavily on it's shoulders...

      http://i3.photobucket.com/albums/y62/Somersrallyslag/photo_zps9a1744c8.jpg

      This meant that grip was still available on the tyre but un-accessible to the driver. Armed with this and the complaints of the teams Pirelli decided to produce a tyre more akin to Motorsports roots and we got the 2013 construction. The tyres were difficult to get into and keep in their operating window by the sheer nature of the tyre not doing enough work, with both Sidewall and Contact Patch to blame.

      Pirelli underestimated the aerodynamic effect this would have and is something that wouldn't show up on their 2010 R30 test car as it didn't utilise either EBD or Coanda Exhausts....

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  3. I'm, afraid I don't agree. When a team has obviously to restrict a car's potential because of a standard part across all teams, because of the very nature of that part's design, I think it becomes an exercise in driving so you don't wear out a tyre. Some conservation strategy is inevitable but when it is so plainly obvious that "playing it safe" is required by all the cars, and the teams that are winning (Ferrari, Lotus) aren't the teams with the fastest car or driver (Mercedes, Red Bull)(I will also add that I think FA and KR are fantastic drivers, but not necessarily in the fastest cars).

    As a spectacle, would you rather be watching flat-out racing with overtakes or teams playing it as safe as possible, not fighting for position and designing cars to be kind to tyres?

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    1. Thanks for your response, I knew when writing this post it would provoke a Marmite response. I have simply tried to cast doubt over the belief that Pirelli are in the wrong by presenting both the mechanical and aerodynamic factors at play.

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    2. The Merc is definitely not a real fast car. Merc is facing the same problem (awful race pace) since 2011. even in 2010 they rarely beat the Renault on race pace. So they are not suffering becuse of these Pirellis.
      Great article Matt.

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  4. An excellent explanation.

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  5. Excellent information! - But, I still think that to a lay man, its all about getting to see the drivers at a 100% all the time. =)

    I guess that is technically impossible to achieve with the current tire set-ups, but still it is a balance that works itself fine in the overall sense.

    I read that Pirelli are changing the tires being provided after the Canadian GP. Is that true? And if so, would it be seen by all teams as being fair? (I doubt Ferrari, Lotus would be too happy)

    Regards!

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    1. I'm fairly sure "lay man" couldn't tell the difference between driver going at 80% and 100% anyway, so I shouldn't be too concerned with a poor lay man hoping to see the drivers driving at 100% all the time.
      To be honest, I've never heard of driving at 100% all the time, until some media lobbyists started throwing it around, and I've been following F1 since 1993. It makes no sense to have a sport so liner that would require only one mode of driving for an entire GP.

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    2. 100% driving virtually never occurs in motorsport so much time is spent managing other factors: Tyres (Tires for my American friends) Fuel, revs, diff settings etc etc. I think some of the problem is we all wear rose tinted glasses and think all the 80's races were classics. Go back and watch them I guarantee they weren't...

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  6. First of all thank you Matt for your brilliant explanation. Specially with that drawing and EBD, it is really brilliant and very easy to digest.

    Well if people are pointing it out the tyre is the only reason why the teams cannot push 100%, I would say they are being a bit mislead by the teams who are not winning. The teams also have to conserve engines and gear-box in order to comply with the rules, but I cannot remember anyone pointing it as a hindrance to pushing 100%. If they were allowed with unlimited number of engines surely they could have pushed it really much harder, and perhaps to that elusive 100%? Same goes for the gear-box. So if you are forced to conserve engines and gear-boxes, then what is wrong with the tyres, specially when it does cut off single team domination and makes the sports spicier. During the Bridgestone time Spanish GP was won who could manage a pole and good start, because it was impossible to overtake in this circuit. The history will support me, as since 1996 Fernando Alonso is the only driver to won it while starting outside the front row. And the fact that Pirelli ensured that procession that we were forced to call racing is changed, and we are blaming them? As the Great Ron Dennis once said " And for that he was punished? Where is the consistency?"

    I am there to support Pirelli, because they have really spiced up the race, as they were told to do. And I struggle to find why would a spectator will complain being confused? Isn't it a good thing that he is confused, keeps him on the edge of the seat all the time and could only grasp the thing in the dying moments of the race. All these great things are happening and we are trying to blame the people who manage to do so?

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    1. As I've alluded to, the media coverage hints heavily at Pirelli being in the wrong when the teams are making bad strategy choices. Ferrari took the initiative on Sunday and ran their own 4 stop race, others then had to adapt which was too late. Kimi continued to run his own race (to the strengths of the E21 which all the teams seem fascinated by instead of extracting their best strategy)

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  7. It can be said louder, but not clearer. Excellent as always Matt.

    Obviously Hamilton's race is a disappointment. To qualify in front row to end 12th is not a good result to digest. But is Mercedes that hasn't done a good job like Ferrari and McLaren have. Red Bull will eventually find the way. They're were going through a similar situation last year.

    Instead of crying and demand a different rubber, they should copy the example of the teams that are succeding with this compound.

    I am seeing real racing. Webber getting out of the pits and Malaysia and defending from Vettel, and Checo and Jenson fighting to death in Bahrein. That's real racing to me. That's enjoyable. Much more than 2011 and 2004.

    What about DRS, team orders? That's what is really affecting the quality of real racing.

    Thanks for your effort. Highly appreciated.

    Jael

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    1. Thanks for replying Jael, I think perhaps I see the race from a different perspective/agenda as I don't follow any team / driver. My best friend was disgusted by the race but he is a Hamilton fan and do saw the race from a skewed perspective watching his driver going backwards. I understand his frustration but Mercedes are to blame in that case as they Mis managed his race IMO

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  8. Fantastic, thanks.

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  9. Thanks, a very concise explanation, however it fails to address my main concern, the inability of the drivers to fight side by side, nose to tail, lap after lap as they once used to be able to do. Your enthusiasm for the cerebral aspect the race could just as easily be satisfied by a series of individual timed runs, which is pretty much what the race turned into after the 1st.lap.

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    1. Alonso overtaking 2 world class drivers around the outside in turn 3 was worth the admission price alone given the rubbish processional racing Barcelona normally brings. He used the Pirelli tyre as it was designed, leverage more grip from them early on, discard them and go again. Barcelona is normally a snooze fest and the mixed strategy (most due to being caught out by Ferrari) offered some salvation. My main point is, Barcelona is a little different to other races as it rarely offers up entertainment so a kneejerk reaction would be silly IMO

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  10. A great detailed but well explained write up! I don't believe that Pirelli are doing a terrible job at all, after all they are just doing what they were asked to do, it's now up to the teams to try and get on top of it, and that's when we'll start seeing drivers racing each other properly again.

    Unfortunately some teams don't seem to want to get on top of it and want to just whine until Pirelli are forced to make a change.

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  11. Thanks for the great article!

    What I don't understand about the race is this: Raikkonen chose a three-stop strategy but Medium tyres on three of the four stints.

    Are we to take from this that (at least for the Lotus on this track) the Medium tyre was actually harder-wearing than the Hard tyre?

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    1. I hinted on twitter before the race that the use of the Medium tyre would be critical at Barcelona. As we know the Lotus is incredibly good on the tyres and this is due to its ability to operate the tyres in a lower temperature window leveraging the grip for a little longer. Kimis choice of 3 Medium and 1 hard stints was due to that cars ability to manage the Medium better. Alonso for arguments sake went the other way and used the upper echelon of the Mediums tyre window in order to extract more grip over a shorter period and jump up the grid before switching to the Hard which has a slightly higher heat threshold giving longevity.

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  12. Really enjoyed this. I had no idea about "Tyre Squirt" and you explained it really well.

    I still can't make my mind up on the tyres situation. Obviously, it is providing more overtaking which everyone wants, but I feel that a lot of the overtakes aren't really contested (I'm not saying that's the case all the time though, as there has been some excellent wheel on wheel action). It feels like a lot of the time the drivers aren't really racing each other, that they're almost running a time trial (that may be a bad analogy).

    Whatever my issues though, this isn't Pirelli's fault. They've done exactly what they were asked to do.

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  13. I remember a race.
    Was in France.

    A driver wins doing a 4 stops race.

    That year, all media call his Race director " A genius"


    4 stops..
    See the race times of 2011 (4 stops, no complain.. ) 2012 (no engine maps, no EBD, no OTB - new coanda efffect) and 2013 (coanda efffect evolution, and 2Kg extra)

    10kg extra of fuel = 0,2s per lap

    2Kg extra =0,04s
    In 66 laps = 2,64s extra due to 2kg extra on tyres.

    In 2011, Vettel races until last lap. Ham at 0,6s.
    in 2012, Maldonado races until last laps. Alonso at 4s

    In 2013, Alonso do last stint at cruise mode.. Kimi at 13s, and under control.
    3 stops vs 4 stops, and a diference of 5s (7,5 - 2,5 of 2kg extra)
    Now, substact pit stop times.. to compare only race time..

    2012 Maldonado, race time,1:39:09,145 - pit stop time, 1:03,667 =1:38:05,478
    2013 Alonso, Race time, 1:39:16,596 - pit stop time, 1:16,851 -extra Kg, 2,64 = 1:37:57,10

    Alonso go 8 secs FASTER in 2013 than Maldonado in 2012

    0,12s per lap FASTER

    5 drivers comparation (2012/2013)

    http://oi41.tinypic.com/ayakxt.jpg

    Button and Kimi.. 4s SLOWER
    Rosberg, same car, SAME TIME
    Vettel... 4s FASTER*
    Alonso, 12s FASTER


    *Vettel was 19s faster in 2013, but with a DT on 2012, had a -15s penalty last year











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  14. Nice article/alternative viewpoint coming from someone who is becoming disillusionment.

    This "Pirelli doing what they're asked to do" line is tiresome excuse. Nobody said the tyres should be changed for this year.

    Arguably the challenge has been too great. I would argue the engineering side has been too great at the expense of the racing/the show for the 'purists' - a great race isn't one that features lots and lots of overtaking.

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