Revealed: Reasons behind unbelievable double Ferrari disqualification

Ferrari suffered a disastrous Chinese Grand Prix, which saw both Lewis Hamilton and Charles Leclerc disqualified following post-race checks. It represents the first time in the team's history that both Ferrari cars have been disqualified from the same race. 

Leclerc had finished the race at the Shanghai International Circuit in fifth but was disqualified as his car was in breach of article 4.1 of the technical regulations. 

Hamilton provisionally finished a place behind Leclerc in sixth, whilst the seven-time world champion suffered a third career disqualification as his SF-25 was in breach of article 3.5.9 of the technical regulations.

Focusing on Leclerc, his car failed to respect the minimum weight of 800 kg established in article 4.1 of the technical regulations. The 27-year-old's car weighed 799 kg after two litres of fuel was drained.

Disqualification is the standard sanction for this violation, considering that no conditions mitigating the irregularity of the car were found by the stewards. 

Leclerc's car was also weighed with a new front wing, to determine the precise weight of the entire car after the driver suffered front wing damage on the first lap of the race.

Almost the entirety of the race was completed by Leclerc with a front wing endplate missing, following contact at the first corner with Hamilton.

Ferrari accepted the stewards' decision in good nature and admitted that a mistake had been made, whilst the team also reiterated that it was not trying to gain an unfair advantage.

What made Leclerc's car underweight?

The Maranello-based outfit's mistake with Leclerc's car could have two causes linked to the Chinese GP, with the event having been a sprint weekend whilst the circuit also had a new surface.

However, neither reason can be considered as a valid alibi for Ferrari, given that the vast majority of the paddock complied with the regulations. The exception is Alpine, as Pierre Gasly was disqualified for also breaching article 4.1.

As it was a sprint weekend, a race simulation was not carried out in practice, meaning Ferrari had no accurate data for the average fuel consumption during a long stint.

Crucially, Ferrari was the only team in the sole practice session of the grand prix not to carry out a mini-simulation with full fuel tanks, impacting the outfit's ability to determine tyre degradation and average fuel consumption in race conditions.

The second condition which could have led to Leclerc's car being underweight is the unexpected durability of the hard tyres. Pirelli had predicted that the Chinese GP would be a two or three-stop race, yet the majority of the drivers completed just one pit stop.

This resulted in greater tyre wear with some stints reaching close to 40 laps on the hard compound, reducing the thickness of the residual tread. In theory, this is enough for a car to be underweight by a kilogram.

However, once again, many drivers completed a one-stop, yet only Leclerc and Gasly had underweight cars after the race.

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Why Hamilton was disqualified

As for Hamilton's disqualification, his car was found with excessive wear of the plank under the floor of his SF-25. 

The three specific points of residual thickness which are measured after a race were all below the minimum thickness of 9 mm, measuring 8.6, 8.6 and 8.5 mm.

A disqualification of this nature is usually linked to the car's ride height, which was increased between the sprint race and qualifying once parc fermé re-opened. 

During a sprint weekend, a team will increase the car's ride height to take into account the fuel load carried in the grand prix; however, Ferrari failed to increase it enough to avoid excessive plank wear.

Given Leclerc's car did not breach article 3.5.9, it is likely that the set-up differences between the two Ferraris also led to Hamilton's disqualification.

The brand-new smooth surface potentially led to Ferrari being confident that it could run the SF-25 lower than it did in the season-opening Australian Grand Prix, where a surprise lack of performance was discovered. 

As summarised by Ferrari in its statement released after the disqualifications had been announced, it was a severe lesson for the Italian team as it continues to understand the SF-25 and how different it is to its predecessor.

In conclusion, the fault with Hamilton's car is an easier mistake to make by Ferrari, than miscalculating the weight of a car.