Why Mercedes gets uncomfortable when the pressure goes up

Tyre performance continues to be one of Mercedes’ few weak points and, while it largely cured that issue through the Hybrid-turbo era, there have been occasions where it has caused problems. Leading up to the 70th Anniversary race, the left-front wear problems in the British GP that led to failures on both cars was fresh in its mind. And the move to softer-compound tyres only meant its headache could get even worse.

Just to throw another variable in the mix, Pirelli decided to increase the minimum tyre pressures too. At the front of the car, the teams would have to run at least 27psi (up by 2psi) and 22psi at the rear (up by 1psi). While this might not sound much, it’s actually a substantial change in F1 terms, causing the tyres to “balloon” as Hamilton described after the race. 

The increased pressures cause a change in the shape of the tyre, altering the distribution of the tread platform and shoulders to the track’s surface. This also results in a change to any brake temperature-transfer bias that the teams might be running.

Mercedes AMG F1 W11 brake flow

Photo by: Giorgio Piola

It’s a hot topic in any case but Mercedes has spent considerable resources on brake ducts in order that they are better able to manage brake temperatures and orchestrate a more accurate transfer of heat into the wheel rim. This has allowed the team to marginalise any hot spots and thus reduce the impact of graining that might ordinarily occur.

It’s a fine balance though, with different brake duct solutions designed and further tailored for each event depending on the split required between cooling and the other brake duct subroutine – namely, aerodynamics. 

Car detail front brake duct, Lewis Hamilton, Mercedes F1 W11

Car detail front brake duct, Lewis Hamilton, Mercedes F1 W11

Photo by: Motorsport Images

In an attempt to further improve the situation at Silverstone, as it didn’t have a specific solution available, the team took to the age-old, high-tech F1 tactic of adding duct tape to the inlet scoop in order to close off flow to some of those channels that supply cool air to the brakes and drive airflow out of the wheel face for aerodynamic purposes.

On the harder range of compounds and lower minimum tyre pressures of the British GP, these changes helped deliver the level of performance required to keep rivals at bay. But the tyre failures at the end of the race were clearly a cause for concern, and required the team to rethink its setup for the second Silverstone race.

Those failures were a contributing factor in the higher minimum pressures mandated by Pirelli and, in combination with the softer compounds, it also raised advice on blistering sensitivity from ‘medium’ to ‘high’. 

The worn rear tyre on the car of Valtteri Bottas, Mercedes F1 W11, 3rd position

The worn rear tyre on the car of Valtteri Bottas, Mercedes F1 W11, 3rd position

Photo by: Mark Sutton / Motorsport Images

Staying off the hards

Racing at the same venue, but with a different set of parameters, means that some of the data you have is helpful, some not so much, and for the teams it’s a case of knowing what information to lean on. Mercedes tends to adapt quickly to issues it has encountered during a season. It made various setup changes to the W11 in order that the rear tyres took some of the pain that the fronts had suffered a week earlier.

The reactive nature of Mercedes sometimes mean it over-reaches – and tactically perhaps this led to some of the troubles. 

Its British GP qualifying had been affected, as Hamilton took a trip through the gravel on medium tyres in Q2, so he had to swap them for his remaining good set to start the race. Meanwhile, Bottas’ right-rear tyre had been damaged during his qualifying lap and was replaced from his remaining new set for the race. It always planned to run a one-stop race for both cars, but this effectively took away the option of a two-stop.

With this knowledge locked in, Mercedes decided to approach the second race weekend differently, and didn’t run the hard tyre at all during practice. In doing so, Mercedes had no real-world data to work from on race day. Sure, the compound was the same as the medium from the race before, but we must not forget how critical the increase in minimum pressures is to Mercedes, whilst elevated track temperatures also played a part.

Max Verstappen, Red Bull Racing RB16

Max Verstappen, Red Bull Racing RB16

Photo by: Mark Sutton / Motorsport Images

Destabilising factors

The other crucial factor was that Mercedes was unable to run its own race, as Verstappen acted as a fly in the ointment. Using the hard tyre in Q2 meant Max had a strategic advantage to the Mercedes pair in the first stint, as he was able to go further into the race and – perhaps more crucially – run at a pace in the early phase of the race that didn’t over-stress the tyre.

Both Mercedes drivers were in a heavy management phase with their medium tyres, with Bottas getting regular reminders over the radio of climbing tyre temperatures, but he was also acutely aware that he needed to maintain a certain lap delta too.

As the Mercedes drivers’ tyres began to fade, Verstappen lent a little harder on his and pressurised the Mercedes pair to pick up their pace, which only led to further degradation. With the exception of Mclaren’s Carlos Sainz, Bottas and Hamilton had both done more laps, 13 and 14 respectively, in that opening stint than the soft runners had done during the opening stint just a week earlier.

When the Mercedes drivers switched to the hard tyre, the requirement to push to keep pace with Verstappen meant they used the tyres in a different way to how Max had at the start of his stint. This set in motion a graining phase, allowing the battle to swing in Verstappen’s favour.

Max Verstappen, Red Bull Racing RB16, comes in for a pit stop

Max Verstappen, Red Bull Racing RB16, comes in for a pit stop

Photo by: Glenn Dunbar / Motorsport Images

Red Bull reacted to this evolving situation exceptionally well. Having masterfully nursed his tyres, Verstappen pitted for the medium-compound tyres and rejoined just behind Bottas. He made swift work of overtaking him, as Bottas had 13 laps on his tyres was already struggling. Knowing that he’d need to make another stop, Verstappen and Red Bull decided to “fully send it”.

Max unleashed a succession of laps that put further daylight between himself and the Mercedes duo. Safe in the knowledge that it had managed the hard tyres more effectively, and with pace in its pocket, Red Bull realised victory was well within its grasp.

Valtteri Bottas, Mercedes F1 W11, comes in for a stop

Valtteri Bottas, Mercedes F1 W11, comes in for a stop

Photo by: Glenn Dunbar / Motorsport Images

In evaluating the condition of the tyres that came off Bottas’ car during the second stint, Mercedes decided to leave Hamilton out at the front of the field. It meant he could try running to the end (although this was always highly unlikely) or it meant he would have sufficient tyre delta (time on fresher tyres) to attack in the closing stages of the race.

Red Bull had the luxury of looking after its tyres, knowing that Hamilton might try a one-stop. As the race wore on, and Hamilton stayed out, Red Bull decided to pull the trigger and told Verstappen to close up.

In fact, Mercedes had already fully committed to the two-stop, and it was just about timing to allow Hamilton enough laps on fresh rubber to get back in the fight.

Hamilton unleashed the W11’s true pace for his last stint, but engaging the hard tyre early in the stint came at a cost once again. Although he made light work of catching and overtaking Charle Leclerc’s Ferrari and his teammate, he couldn’t put a dent in Verstappen’s commanding lead.

Valtteri Bottas, Mercedes F1 W11

Valtteri Bottas, Mercedes F1 W11

Photo by: Glenn Dunbar / Motorsport Images

Now we move on…

This weekend, Barcelona in August is going to be an entirely different prospect to the conditions that the teams encoutered during pre-season testing in February. Hotter temperatures on another circuit that’s extremely demanding on the tyres will be music to Red Bull’s ears.

Thankfully for the ‘black arrows’, Pirelli has opted for the harder range of compounds, with a C1 hard tyre through C3 soft. But with cars producing such high levels of downforce this year, and the tyre blow ups from Silverstone in the back of their minds, we could once again see Pirelli prescribe higher minimum tyre pressures to increase the safety margin.

A consequence of the higher minimum pressures seems to suppress some of the aerodynamic stability woes that Red Bull has suffered in the opening rounds.

After its Silverstone pains, Mercedes will have a better understanding of the issues at hand and perhaps have some answers – albeit hotfixes – should they face a similar situation in Spain. But just look at its response between races in Austria to see how quickly this team can adapt to issues that rear their head, although the recursive nature of tyre issues does suggest an underlying inability to cure the issue entirely.

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