Exactly why Valentino Rossi seems to be the only Yamaha MotoGP rider still struggling with rear tyre wear issues continues to be a cause of debate.

The nine-time world champion spent much of last year dogged by the problem and, despite a change of tyre design by Michelin and promising signs in winter testing, suffered a recurrence of the issue during practice for this weekend's Spanish season opener.

Speaking to Italian TV, Michelin Motorsport Two-Wheel Manager Piero Taramasso suggested that Rossi's riding style means he does not hang far enough off the bike, thus stressing the edge of the tyre more and causing the overheating.

"I don’t agree with Taramasso," responded Rossi, when asked about the idea on Saturday evening at Jerez. "I heard the interview, but if you look at the images I am a lot out of the bike because we work a lot under this point of view and with the Bridgestone tyres we were also more out of the bike than now. Now with the Michelins, you cannot stay too much outside [of the bike]. 

"I don’t think it's true. The problem is not that. Because for example Dovizioso is another rider that his style, he is completely 'on' the bike, but he doesn’t finish the tyres. So for me, it's not that problem."

Rossi and his Monster Yamaha team continue to hunt for a solution, the Italian highlighting the softer nature of the current tyres and his size (69kg/181cm) as possible factors.

"Usually in my career I always ride and prefer the hard tyres, at the front and rear. In the past I did the best races in my career with hard tyres," he said. "Now the Michelin tyres are very soft, a very soft casing and very soft rubber, and for me it's not easy.

"Also because I am maybe the tallest, for sure more than the average [rider] height. I'm very slim, but my weight is quite high because of my height."

Nonetheless, Rossi made clear it is 'his problem' to solve.

"I understand Taramasso; it's my problem, not a Michelin problem," he said. "Because anyway the other guys are fast. So I agree with him that we need to find a way, but I don’t agree that the problem is I'm not far enough out of the bike."

Unfortunately for Rossi, who finished last season with a 16-race podium drought, there is nothing obvious when comparing his data with fellow Factory-spec M1 riders Fabio Quartararo and Maverick Vinales.

"Sincerely when you look at the data we are very similar," he said, adding that Vinales is particularly strong in braking.

Quartararo and Vinales will start first and second on Sunday's grid, alongside Honda's reigning world champion Marc Marquez. Rossi was one-second slower in eleventh, directly behind Franco Morbidelli on the A-Spec M1.

"Today we improved compared to yesterday, especially in the morning when my pace and the hot lap was good," Rossi said. "In the afternoon when it was a bit hotter I suffered more but I have improved on my pace from yesterday.

"I think the top three guys are a bit faster – Maverick, Quartararo and Marquez – but after there is a big group of riders with a very similar pace. We will see tomorrow because we want to try to improve our pace, be a bit faster and we'll see."

Whatever the outcome of the opening races, it will not change Rossi's plans to ride for Petronas Yamaha in 2021.

"We are agreed on everything. We are not in a hurry and we still have some details to fix [before signing the contract] but the situation is like I said yesterday and the result of the first races will not change a lot."