Michelin says it couldn't find any problem with Francesco Bagnaia's rear tyre in its initial analysis following the Emilia Romagna Grand Prix.
Factory Ducati MotoGP rider Bagnaia suffered an inexplicable drop in pace after losing second place to team-mate Enea Bastianini on lap five of 27 at Misano, a problem that also threatened his place on the podium as Gresini's Marc Marquez closed in.
But even more curiously, the Italian was able to regain his speed in the middle portion of the race, leading to him breaking the 1m31s barrier and setting the fastest lap on the 16th tour.
In his post-race comments, Bagnaia pointed the blame squarely at MotoGP's official tyre supplier for his contrasting fortunes on Sunday, saying it was the first time a rider had to encounter a rear tyre that "didn't work" for the first 15 laps.
"The state of mind is that I'm pissed off. Not with Michelin, they can't help it. I can't be angry with someone who does something, but doesn't do it on purpose," he said after the race from which he eventually crashed out on lap 21.
"But it pisses me off: you take pole, you win the sprint and in the race you improve the start, being first on the first lap, and to see you [being] passed, with the others taking away almost three and a half seconds because you can't push, it is something that really pisses me off."
While Michelin is awaiting more data to complete a full analysis, its initial verdict is that tyres cannot be responsible for the wild swings in Bagnaia's pace at Misano.
It argued that if there was a defect in his rear tyre, then he would have been slow throughout the race and not been able to set a lap time that was good enough to qualify on the third row with over 10 laps of fuel on board.
"Pecco was in front for the first four laps, then he had a drop that we can't explain: for four or five laps he lost three tenths.
"We have to understand where this is coming from, whether it's something to do with the track, the bike or the tyres," Michelin's two-wheel motorsport manager Piero Taramasso told Autosport.
"But from lap 12 onwards his pace came back and on lap 16 he set a fastest lap of 1m30.8s, just eight tenths off pole and the track record. He was coming on strong and looked like he could catch Bastianini and Martin, then he crashed.
"We are analysing it, but for the moment we only have his comments and lap times. When Ducati gives us the data as well, we'll try to understand together what caused that drop. It will take some time, but we would like to understand what it was due to, because there are always new things to discover.
He added: "The strange thing is that the lap times don't match Pecco's comments. He says the tyre didn't work from the start and only did so from lap 12 onwards. In reality, the times of the first four laps were good, so it's after that that we have to understand where the drop comes from."
The new tyres introduced by Michelin this year have largely been a success, with riders successfully able to break long-standing lap records at most circuits.
Even in qualifying for the Emilia Romagna GP, Bagnaia was nearly able to set the first sub-90 second lap time at Misano as he clinched pole position on the Ducati GP24.
However, there still have been some complaints from riders about tyres occasionally not performing at the optimum.
These remarks follow Jorge Martin accusing the French manufacturer of robbing him of the title in 2023 with what he felt was a faulty tyre in the penultimate round in Qatar.
