In a press release issued today, Formula 1’s official tyre supplier Pirelli have published the difference in lap time between the compounds of tyre used in the test at Barcelona this week.

For 2019, Pirelli has changed the way that tyre compounds are being labelled. There are five base compounds, named C1 to C5, and three will be picked for each race – and will be called soft, medium and hard for the events.

This new strategy has been chosen to simplify the situation at any given race weekend, enabling fans to understand each driver’s choice more clearly.

Pirelli decided to bring all five compounds to testing, with the C1 (the hardest) estimated to be 0.8 – 1.0 seconds slower than the C2.

“The C1 in this condition is a bit too hard because it is cold. In my expectation if we come here with C1 for the race this delta should be less because the C1 is working better and will be closer to the C2.” says Pirelli boss Mario Isola.

Between the C2 and the C3, Isola estimated a gap of 0.7 seconds, while he said that the gap between the C3 and the C4, plus the C4 and the C5, was 0.6 seconds.

Armed with this knowledge, TJ13 has applied the difference in compounds, or delta to coin the technical phrase oft used by F1, to the latest Pirelli fastest time sheet for the whole 4 day test this week. Yes there are many other variables involved, but when considering this evidence and the GPS data published last night on TJ13, it certainly points to the Italian outfit as being the fastest over a single lap, and on a race simulation.

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Pirelli’s tyre gap estimate:

C1 to C2: 0.8 – 1.0 seconds

C2 to C3: 0.7 seconds

C3 to C4: 0.6 seconds

C4 to C5: 0.6 seconds

Isola said that having approximately 0.7 seconds gap between the majority of compounds was in line with what the company had hoped for this season.

“The track is not very long, so 0.7s is a good number considering that the target was 0.8s and 0.9s,” he said. “So on a longer track that could happen.”

So there is a slight caveat to this delta data; the C5 or the softest compound doesn’t fully suit the Barcelona track, it’s perfomance can decrease due to ‘cold graining’ experienced in low temperatures and abrasive tarmacs if the car and driver are too aggressive.

“Plus the C5 is not the compound for this circuit” admits Isola

“The C5 struggles a little bit to guarantee a very fast lap. Also, one lap is difficult to achieve with the C5 in Barcelona, considering the circuit is more aggressive and the tarmac is rougher than one year ago.”

Regardless, when we see Vettel set that time on day one with very little rubber on the track and zero aero adjustments beyond what is possible in a day, Ferrari certainly looks mighty at this stage of testing.

Consider too, the top four cars are all powered by Ferrari. Could we see a new engine domination for 2019? Test number two next week will be very interesting indeed.