Despite shedding 4kg for the start of the 2018 MotoGP season, Danilo Petrucci is preparing to embark on another gruelling winter weight-loss programme ahead of his dream factory Ducati move.

The Italian, 14cm taller and 11kg heavier than future team-mate Andrea Dovizioso, fears that set-up work alone cannot solve his ongoing rear-tyre overheating problems.

"We were working this weekend, especially for next year," Petrucci said. "But we are not solving our problem with the rear tyre.

"It's not a problem of tyre consumption, it's a problem of high temperature.

"We tried many solutions on the bike, but I think the big work I have to do is on myself this winter, to lose as many kilos as possible.

"It will be tough, but I have a big opportunity next year and I want to do as much as possible."

Petrucci's official start-of-season weight was recorded as 78kg, for a height of 1.81m.

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Petrucci explained: "My tyre consumption is not so high, but the temperature during the race is much, much higher. On average, 15-18 degrees more and this affects the performance much more than the consumption."

In other words, because Petrucci's tyre is hotter, he has less grip.

"Sincerely I don’t know if I have to change something more on my riding style," he said. "For sure I have to work, to understand how to ride and not overheat the tyre.

"But at the moment I'm struggling to do it and the problem is the races we have in front of us like Thailand, Japan and Malaysia will be hot and we have to understand how to ride faster.

"Even on the straights I have physically much more load on the rear tyre. I can cool down the front tyre on the straights, but the rear not so much."

The overheating issue was then compounded by a tyre vibration in Sunday's Aragon race, leaving the Pramac GP18 rider to finish in seventh place (+14.285s).

"I was with the front group and by lap 10 my gap with [race leader] Dovizioso was around 2.5s. Not so much. But when I started to push, I started to have this vibration on the left side, which happens when the rear tyre moves on the rim.

"This affected me a lot on the left side and, for the last ten laps, even on the right side. It was very difficult. I almost crashed two or three times.

"I cannot be happy because in Sachsenring I challenged for the podium until the last corner. In Brno I finished sixth, three-seconds from the winner. Red Bull Ring, in fifth place. Here it's seventh, but 14-seconds from first and it's not what we are looking for."

The positive news was that Petrucci still managed to pull back points on his nearest championship rivals.

"I was lucky to recover some points from my direct challengers for fifth place in the championship.

"I recovered some points on Cal because he crashed and for sure he could have been faster than me in this race. Then I was able to recover some points on Vinales and Zarco, but the Yamaha was in trouble here.

"But for sure it's not a race to remember."

Meanwhile, during pre-season testing in a sweltering Thailand, Petrucci revealed his weight could reach over 90kg with full safety equipment, plus sweat at a hot track:

"Just because I was curious, I weighed myself naked in Malaysia [test] and I was 77kg. Then my weight with the wet leathers was 91kg! At least 3-4kg was from sweat and I think 2-3 kilos from the new airbag system.

"I tried to lose a lot of kilos over the winter and when I saw the weight of the wet leathers, with the airbag, I thought 'no!' But I'm not the only one in this situation."

The Italian joked: "I sweat like three riders! I don't need a camelback [drink system], I need a whole camel on my back!"

Team-mate Jack Miller, riding the GP17, finished in ninth place at Aragon.