F1's official tyre supplier has been evaluating some minor tweaks to next year's tyre compound selection in a bid to tidy up some minor issues.
One of the areas it thought about changing was making the C2 – the third hardest compound in its selection that runs from C0 to C5 – slightly softer.
This was because it has proven to be quite close in performance to the C1, and slightly too far away from the C3, so a slight shift would have helped make the gaps between compounds more equal.
As part of F1's tyre test rules, Pirelli handed out two sets of the prototype softer C2 compounds to each driver for Friday practice at the Japanese Grand Prix.
However, initial feedback from the running of the modified C2 showed that it had not delivered the performance step hoped for, which means that Pirelli will now almost certainly stick with the current compounds into 2024.
Asked by Motorsport.com about the conclusion of the Friday test in Japan, Pirelli's head of car racing Mario Isola said: "Looking at the data, and also considering the track evolution, I believe that the prototype doesn't have the grip that we were looking for.
"So, we will probably stay on the current C2 for next year. Without a clear result, a clear step in grip, there is no reason to change and introduce a new compound when we have the current C2 that is working well.
"It is just a bit too close to the C1, and a bit too far from the C3, and that's why we wanted to test the prototype."
Pirelli said that the test of the revised C2 was a one-off, so there was no plan for any further evaluation before making a decision.
At this month's Mexican Grand Prix, however, Pirelli will test a revised C4 prototype that it hopes will make its characteristics better.
"We want to test the C4 in Mexico with the same system, so no dedicated FP2 for us, but just two sets of prototypes [for drivers].
"The target is not to move the C4 [compound], because the position is good. But the C4 showed quite a bit of graining during the season.
"So, we want to improve the mechanical resistance and to have a wider working range, because the feedback from the teams is that the C4 is a bit peaky."
As well as the C4 prototype test planned for Mexico, Pirelli has also announced that it will take softer compounds to the grand prix than it had last year. The hard, medium and softs will be C3, C4 and C5.
