Rinaldi struggled for one-lap pace all weekend at the El Villicum circuit, qualifying seven-tenths behind teammate and pole-sitter Scott Redding in ninth place.
He made a solid comeback to finish on the podium in the opening race, but the 10-lap Superpole again compromised his chances for the second long-distance race of the weekend, leaving him eighth on the grid.
The Italian says the tire grip issues are “mentally frustrating”, explaining how he is unable to extract more performance from his bike when conditions allow others.
“My race was good, I lost a lot of time overtaking [Leon] Haslam and [Michael] van der Mark and that got me out of the fight for the podium, ”he said. “So if I look at this, I was pretty happy.
“I knew our potential was that of a Ducati 1-2 but we know our race was compromised by qualifying and the Superpole.
“The problem is that when the track allows you to have more grip, each driver can use it to go faster, [but] I can’t go any faster. There is this same problem that I have had all year and it is so mentally frustrating.
“It’s the same since Aragon and we are working a lot to understand why, but we are not in a position to say ‘this is this or it is that’. Also, if they told me [it is because of my] riding style or how I use the throttle, I’m going to work on that.
“But we have no reason to explain this and my driving is good to win a race and the next race is not good [enough].
“My driving is good for the 18th lap of the race [at] 1m37.9s. But in qualifying I did 1m38.3s with qualifying tires so it’s so strange.
“With more grip I have more problems and everyone goes faster by at least half a second. That’s why I’m really, really frustrated because I put my 120% and also the The team is 120% but we have no answer.
Rinaldi’s results on Sunday contrasted with those of teammate Redding, with the British rider finishing just 0.046s behind winner Toprak Razgatlioglu in the Superpole race before securing a resounding victory in the second long distance race of the weekend.
But Rinaldi doesn’t think their weight difference – the Italian being lighter of the two – has nothing to do with his struggles on the Ducati.
“I don’t know if it’s the weight or something else that keeps him spinning [and not] I have the same problem as me, “he said.” But he will have another problem.
“So my weight has advantages but disadvantages and it’s the same for him, so I’m not complaining about my weight and I’m not saying he can put more weight on the rear tire because it is. is bullshit.
“But for sure I have a problem he doesn’t have and it’s something you need to sort out. This year he was better than me at solving his problems.