Pirelli decided for 2018, by request of Mercedes, Ferrari and McLaren, to take measures to prevent blistering of their compounds at a select number of circuits – Barcelona, the upcoming French GP at Paul Ricard and Silverstone.
The prevention of blistering tyres at these particularly abrasive circuits were a concern to the top teams and Pirelli decided the best thing to do, in a rather surprisingly amateurish fashion, was to reduce the thickness of its tyres by 0.4 millimetres.
Their external dimensions were unchanged because they were produced in the same moulds thereby keeping tooling costs to a minimum.
The Spanish Grand Prix was the first race of 2018 to use these modified ‘skinny’ tyres, and it’s fair to say the change benefitted Mercedes greatly. The team dominated the race after a slow start to the season, whereas Ferrari struggled on Sunday to keep their tyres good.
“I think we struggled all weekend with sliding around a little bit more,” Vettel said after the race having finished 4th; some 28 seconds behind Hamilton, the eventual winner.
“Obviously we’ve heard many times that they are the same compounds and they are not harder. But I don’t think you need to be a genius to [work] out that if you if you skim the tyre it ends up being harder. It’s one or the other, we may as well have just run harder tyres. So maybe it didn’t suit our car as good as other cars.
However Vettel added it’s up to Ferrari to master the revised rubber. “It has to suit our car better than other cars,” he said, “that’s the way we want [it].”
One part of the puzzle we later found out at Monaco some two weeks later, was that Ferrari had changed their rear suspension as a planned update before the Spanish GP at Barcelona. The update incorporated revised geometry to better sculpt airflow in a bid to improve diffuser performance.
The new suspension upright had a much more aggressive transition – allowing a wider and flatter surface – which was designed to help improve the aerodynamics of the car in that area. The consequence of which was severe tyre degradation on the revised Pirelli ‘skinny’ tyres.
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The first in-season test then occurred at the Barcelona track and many assumed that Ferrari were using the test to try and understand what went wrong in the race. Then Ferrari elected to revert to the previous spec rear suspension for Monaco to prevent the issue occurring again.
This weekend see’s a return to the French Grand Prix, this time held at the Paul Ricard circuit – and the 2nd nominated by Pirelli track which will see the ‘skinny’ tyres return. Mercedes will be no doubt licking their lips.
But should they?
Vettel confirmed at Monaco that Ferrari did indeed use the test at Barcelona to try ‘a couple of ideas’ in trying to return the Ferrari car back to being kind on it’s tyres, particularly the skinny type.
“It was good we had the opportunity on Tuesday/Wednesday to get into the race situation again to understand a bit better with time and laps.” admitted Vettel
“There are a couple of ideas we have and things we believe that may have caused a weak race or weak pace during the race.
“But for [Monaco] it is not that relevant because it is a completely different track.
“But going forward, time will tell whether we found a good direction.”
And it certainly seems they have. Paddock rumour and sources from Italy have revealed that a significant upgrade is coming for the race at Paul Ricard this weekend. An upgraded rear suspension designed to cope with the skinny tyres from Pirelli, but also improve the aero function of the suspension arms in a bid to improve downforce. The trick they never got working for Barcelona; improved aero but not at the expense of tyre life.
Only time will tell if the upgrade gives Ferrari the continued momentum in their bid to make Sebastian Vettel world Champion for 2018.