Sebastian Vettel has cast doubt on whether the 2019 Formula 1 technical rule tweaks will deliver its intended improvements to racing this season after trying to follow some of his rivals on track during pre-season testing.

For the new F1 season rule-makers have enforced changes to simply front wing designs and make rear wings bigger with the goal of making it easier for cars to follow each other while racing. Theoretically, the alterations should increase overtaking opportunities by reducing the impact of turbulent air produced by the leading car.

While Vettel believes the true test won’t come until racing begins at the Australian Grand Prix next weekend, he remains unconvinced having followed a number of F1 cars at Circuit de Catalunya during the two pre-season tests.

“I have followed other cars last week and this week,” Vettel said during testing. “It’s always difficult to say in testing and difficult to judge because you are on different tyres, different compounds and age, different compounds. So far it was still tricky to follow and to overtake.”

The impact of the 2019 F1 rule changes received a mixed reception across the rest of the drivers, while most opted to reserve their final assessment until in a racing scenario, with Renault’s Nico Hulkenberg feeling the bigger rear wing made the biggest impact during testing.

“We have a lot more drag with the big rear wing,” Hulkenberg said. “So, you have less of that sensation - it is like pulling a parachute now across the straight.

“You see that massive rear wing in the mirrors and that has an impact on the feel of power.”

F1 rule tweaks were triggered last year over concerns on the sport’s racing spectacle being dampened by the current technical rules with the cars badly hit by turbulent air thrown up by following other cars closely.

The alterations for 2019 have been billed as a stepping stone towards a bigger rules overhaul set to be introduced in 2021.