BARCELONA, Spain -- Sebastian Vettel suspects Mercedes' impressive pace in qualifying on Pirelli's softest compound is linked to changes to the tyre's tread depth for this weekend's race.
Lewis Hamilton put an end to Vettel's run of consecutive pole positions on Saturday as Mercedes took its first front-row lockout since last year's Abu Dhabi Grand Prix. The return to form came at one of the most aero-sensitive circuits on the calendar, but also after Pirelli reduced the thickness of the tread by 0.4mm on its tyres to combat overheating.
During pre-season testing at the Circuit de Catalunya, a number of teams -- most notably Mercedes -- struggled with excessive overheating and blistering on the circuit's newly-laid track surface.