Day 4 of the F1 2026 Barcelona shakedown delivered a crucial reliability-focused session as teams continued preparing for the new Formula 1 regulations.In this video podcast report, we break down everything that happened on Barcelona Testing Day 4, including Mercedes completing the most mileage of any team, Aston Martin finally making their long-awaited debut with the AMR26, and mixed fortunes for McLaren after a fuel system issue limited their running.We also discuss Ferrari’s continued programme with Lewis Hamilton, Racing Bulls’ steady progress, and which teams chose not to run as the Barcelona shakedown nears its conclusion.With just one day left before attention turns to Bahrain, Day 4 gave us important clues about reliability, preparation, and which teams look most comfortable under the new 2026 F1 rules.DAY 3 REPORT: https://www.youtube.com/watch?v=q-L4LnMb75oPRE-SEASON POD: https://www.youtube.com/watch?v=rVVlJOIyLZs #F12026 #F1Testing #BarcelonaTesting #Formula1 #F1News #astonmartin #oscarpiastri