Rossi raced 2016 chassis - 'it was better, but…'

Once again in trouble due to low-grip conditons at Valencia, Valentino Rossi and Movistar Yamaha team-mate Maverick Vinales felt they had little to lose by making a surprise last-minute switch to the 2016 chassis for race day.

That was the same design that Tech 3 star Johann Zarco took to second on the grid and went on to lead for 25 of the 30 race laps.

But for the factory riders, starting seventh (Rossi) and 13th (Vinales), the change meant sacrificing two days of set-up work and starting from scratch in morning warm-up.

"Yesterday night we changed the chassis, we take a chassis from 2016 to try to understand the way," said Rossi, speaking in the Valencia paddock on Sunday evening.

"We did this because the programme was to try the [2016] bike at the test on Tuesday and Wednesday anyway. So we said, 'why don’t we try today?'

"For sure it was a risky choice, but with my [2017] bike we know more-or-less where we are and sometimes in a race you can understand more than in ten days of testing."

Despite Zarco's form, there would be no transformation in results for the factory riders during the grand prix.

Rossi finished the season finale in fifth - gaining places when the factory Ducatis crashed, but being passed by Suzuki's Alex Rins - while Vinales was a cautious twelfth after rear tyre vibrations.

Both were sure the 2016 chassis gave a better feeling, but with it - Rossi cautioned - came a recurrence of rear tyre degradation issues.

"Unfortunately, it is not like you put [the 2016 chassis] and everything is better," Rossi explained.

"It is quite difficult to improve the bike a lot in just one day and at the end I think it was more-or-less the race that I could do with my [2017] bike from yesterday. We are in big, big trouble with the tyres, we don't have grip and it is very difficult to ride.

"But I think we understand something interesting.

"This [2016] bike is easier to ride and you feel better in general. Sincerely, it is what I felt last year when I tried [the 2016 alongside] the new one! But it is also true that we are more in trouble with rear tyre degradation [with the 2016]. So we have some other problem.

"I did the meeting with the Japanese and they are worried like me. But sincerely I don't understand which one [2016 or 2017] will be the base for next year's bike.

"Something strange that we don't understand is that I was 20-seconds slower than last year, with the same tyres and same chassis. But it is also very strange to understand why the race was 15-seconds slower than last year, considering the conditions are exactly the same."

Looking to the future, Rossi said further back-to-back chassis comparisons are likely during this week's official test.

"Now will be a very important period to try to improve before the next championship," Rossi said.

"For me, we have to work in different areas to reduce the gap. Electronics side, but also about the dynamic behaviour of the bike. So it will be an important period for sure. I will try to give all my support. I think - and especially I hope - that we can recover."

Rossi lost out on fourth in the world championship to race winner Dani Pedrosa.