Four-time F1 world champion Vettel joined Aston Martin for 2021 following his exit from Ferrari, but has failed to score any points in his first two races.
Vettel was knocked out in Q1 on debut for Aston Martin in Bahrain and finished 15th, and qualified 13th at Imola before retiring late on due to a gearbox issue.
The German driver was outqualified by team-mate Lance Stroll at both races, and has spoken about his need to take time to get up to speed with the AMR21 car and build his confidence.
Aston Martin team boss Szafnauer said that Vettel was struggling with rear-end instability on corner entry as he was not finding enough consistency with the car.
Sebastian Vettel, Aston Martin
Photo by: Glenn Dunbar / Motorsport Images
“Here in particular, it’s a little bit [of] having instability going into the corner at the rear, but I think the biggest difficulty is the variability in it,” Szafnauer said.
“So if it does the same thing time and time again, then you can get to the limit and stay there and go a bit quicker.
“But when it’s variable and you don’t know what to expect, I think that’s the issue.
“The more you drive a car, the more you’re feeling it or with it, then the more you can predict that kind of stuff.
“It’s just a matter of seat time.”
Aston Martin has been vocal about its struggles in the early part of the season, stemming from the rule changes for 2021 that saw downforce levels be cut back.
Szafnauer felt Vettel’s lack of rear-end confidence stemmed from the lost downforce for 2021, but that upcoming upgrades would seek to remedy this.
“That cure is going to come from a lot of good work in the wind tunnel, and just bringing new parts of the car in the next few races to get some of that load back that we lost at the rear,” Szafnauer said.
“That’s exactly where that’s coming from.
“There is a path. You’ll see some improvements coming at the next race, for example, and thereafter, there’ll be some other upgrades as well.
“So it won’t be the last one.”