Why Kubica's biggest F1 gripe needs sorting

The intensity and commitment Robert Kubica puts into his job makes him pretty demanding to work with, especially when it comes to getting a racing car that he likes.

His strong opinions are not just reserved for the process of making himself faster - he is equally forthright when it comes to talking about Formula 1's bigger picture. That's why he is not ashamed to admit there is one thing that has shocked him about the current F1 cars: just how cumbersome they are.

"Formula 1 has changed completely from a technical point of view and from a car's point of view," he says, talking about the jump he experienced when he got his first taste of the wider, faster cars.

"If I had to highlight - as there were so many changes - the biggest [thing] affecting the driving is the weight of the car. When I drove last time [his final test was in 2011], the minimum weight was 620kg. That's nearly 120kg less than now. If you take 100kg off these cars, it's around 3.5 seconds. But it's not only lap time.

"The lap times of the current cars are very fast, but the way you achieve that is completely different. At low speed my biggest shock was how heavy they feel and how slow they are to react.

"If you ask the drivers about the difference between low-fuel qualifying and high-fuel, it's a completely different category. Imagine, our high-fuel in the past was the qualifying weight of the current cars!"

This is not the first time that a driver has expressed a gripe about the rampant climb in car weight that's taken place in F1 over recent years. Lewis Hamilton called it "ridiculous" after it hit home to him just how much things had changed over the past five seasons.

Before the turbo hybrid era, cars weighed 642kg (including drivers). In 2014, thanks to the introduction of the turbo hybrid engines, the minimum weight went up to 691kg.

When F1 elected to revamp the aerodynamic rules for 2017, the wider cars and bigger tyres led to further bulking-up. The cars ended up at 728kg last year - before a further 6kg was added ahead of this season to take the halo into account. It means that from '13 to now, F1 cars are nearly 15% heavier.

But what's perhaps more of a concern in the short term is that despite a growing awareness that F1 has a weight problem, the likelihood is things are going to get worse before they get better.

Today's figures are a world away from the first minimum F1 car weight limit of 450kg in 1961

For 2019, another driver/car weight rise on the cards, taking the combined figure to 740kg. Plans are also in place to increase fuel capacity by another 5kg to 110kg, which means the race-starting weight of a grand prix car will be 850kg. That's not really in the realm of a nimble single-seater.

That weight is not far removed from an LMP1 car, with those hybrid machines having to hit a minimum dry weight of 878kg. Interestingly, Porsche stripped out 39kg - taking the weight down to 849kg - when it modified its 919 to gun for lap records after retiring the car from competition at the end of 2017.

Such figures are a world away from the first minimum F1 car weight limit, which was set at 450kg in 1961. Throughout the early '90s, the figure had only risen to 515kg before a move from '95 to include driver weight in the measurements lifted it to 595kg.

With next year's rules effectively splitting the driver and car - with an 80kg reference taken for a driver and their seat - it means the cars alone must hit 660kg.

This all means an increase of 145kg since the mid-1990s, and around 100kg from just five years ago. If we take the normal calculation that 10kg of weight equals 0.3s per lap, then based on that alone the current generation of cars are 4.35s slower than 25 years ago, and 3.0s slower than five years ago. Thankfully we've had some performance added to them in other ways.

But the weight issue is not just a matter of driver preference, because it also has implications for the racing, and it should be something that F1 takes into account in the future.

Hamilton said his eureka moment about the weight issue came when thinking about the physical challenges Pirelli has faced in producing tyres for the current cars.

"I'm just realising when I got to Formula 1 the car was like 600kg, and now it's 100kg heavier - I think that makes a big difference," he says. "They don't have to change the regulations much to make the cars three seconds quicker, just make the cars lighter. They are super-heavy."

Kubica concurs that some of the complications caused by the current generation of tyres are a consequence of F1's cars being so heavy.

"The tyres are a consequence of how the cars are built and of the regulations," he says. "If you take out 100kg, the tyres will behave much easier - it will be a much easier life. There will be less degradation. I am sure Pirelli will have a much easier life with 100kg-lighter cars.

"We always complain about degradation and a very narrow operating window with the current tyres, but it's a consequence of what's actually needed. Formula 1, from a tyre point of view, has become much more complicated for a driver because the tyres are much more sensitive.

"But also from the supplier - in this case Pirelli - because the tyres have to be built up for much more energy. The cars are very fast, the cars are very powerful, so this is stretching the tyres a lot. But additionally, the 100kg makes a huge difference."

So, the question is whether F1 has the commitment to put its cars on a diet. Ross Brawn said last year that it was an "ambition" of F1 chiefs to reduce the weight of the cars, but creating rules to achieve that will not be easy.

"If F1 went back to lighter cars, I think it would significantly increase the chances for overtaking" Robert Kubica

For example, F1's plan to get rid of the MGU-H could have weight consequences. If the missing energy that it produced must come from the internal combustion engine, then that will require more fuel to get through a race - and that means more weight.

With F1 determined to make sure that the rules from 2021 produce a bigger spectacle, it should prioritise the weight issue - not just for the drivers, but also for the racing.

Kubica is convinced that while having lighter cars is not the only thing needed to move F1 in the right direction, it would certainly be a good start.

"The DRS is helping, but it's making fake overtaking," he says. "Again, it's weight for me [that's important], because now people can't stress the tyres, the tyres are already overstressed most of the time. So you cannot take a risk of forcing them because you will make them worse.

"If you'd go back to lighter cars, with a bit less aero, especially on the braking to make your braking more difficult, I think it will significantly increase the chances for overtaking. Then the tyres will last longer. They will be not be so stressed.

"You could force them more. You could squeeze this kind of braking and you will not be affected from locking and flat-spotting so much. It's a combination - there is not one medicine."

Lighter cars may not then be a magic bullet for a better F1, but Kubica's gripe is real and the weight issue should be given priority treatment.