F1 behind the scenes: Tool failure left George Russell with “heavy oversteer” in Barcelona. Mercedes pit stop error cost George Russell pace in Barcelona.

Despite taking pole position on Saturday and finishing second under the chequered flag, the Barcelona weekend was not one of the easiest of the season for George Russell. From the middle phase of the race onwards, the British driver began to struggle with increasing understeer and a gradual drop in tyre performance.

This scenario not only gave Lewis Hamilton the opportunity to make his three-stop strategy work, but also allowed Andrea Kimi Antonelli to quickly close the gap and become a serious threat before the final pit stop, when the mandatory hard tyres were fitted to make it to the finish. It was at this stage, however, that something went wrong for the Mercedes driver.

During the second stint, Russell had reported understeer, which should have prompted the mechanics to make an adjustment to the front wing during the pit stop. The aim was to add front-end load, rebalance the car and reduce the tyre degradation that had limited him towards the end of the second stint.

The problem was that, during that very pit stop, a failure occurred with the equipment used to adjust the front wing angle through the access hole located in the nose of the car. As a result, instead of correcting the issue, Russell went from driving a car that tended towards understeer to one that was heavily oversteering.

The Mercedes suddenly became much more front-end focused, with a less stable rear end. It was a balance characteristic that the British driver does not particularly enjoy, especially on circuits with low grip levels and high tyre degradation.

“During the final pit stop we adjusted the front wing incorrectly because of an issue with the tool used to make the wing adjustment. This meant he drove with a very oversteery balance, which certainly compromised his pace in the final part of the race,” said Mercedes Deputy Team Principal Bradley Lord during the team’s traditional post-race debrief, explaining the issue that affected Russell from the final stop onwards.

Indeed, the data also appeared to confirm the problem. Russell’s final stint was relatively disappointing in terms of lap times, as he lost an average of around seven tenths of a second per lap to Lewis Hamilton. It was a significant gap that became particularly evident towards the end of the race, when the tyres started to wear more heavily on the rear axle, which was already under stress due to the unstable oversteering balance.

That does not necessarily mean Russell would have been free of performance issues in the final stint. Even in the opening laps, while dealing with traffic and adapting to the altered balance, his pace compared to Hamilton was not especially strong. Recovering a significant portion of the gap that the Ferrari driver had previously managed to close would have been extremely difficult regardless.

However, over a longer run, particularly at a circuit such as Barcelona, where even on Friday the hardest tyre compound had shown a tendency to slide, having a car that is excessively biased towards either the front or rear axle can have a major impact on tyre wear.

Pirelli later reduced tyre pressures slightly in order to increase the contact patch and, above all, limit the pressure build-up once the tyres stabilised in the extremely hot conditions. Even so, an imbalance in the car’s setup can significantly influence tyre degradation, and in Russell’s case it ultimately made the final thirty laps much more difficult than they should have been.