F1 2021 rule changes: what teams aren’t showing us on their new cars

Stability in uncertain times: that was the idea behind the 2021 Formula 1 season following the havoc wreaked last year by Covid.

But despite pushing the large-scale car design regulation changes back to 2022, there are plenty of changes that could alter the running order this year.

Bringing the creative minds of F1 designers to a standstill isn’t possible, so measures have been introduced to cut downforce by 10 per cent and curb the ever-increasing speed of the cars.  The series’ first cost cap has been brought in, along with tokens that restrict development and rules that reduce the ability of teams to copy rival designs.

It all added up to a busy winter for designers and the potential for teams to steal a march on rivals. Which is why all of the 2021 cars launched so far are expected to look significantly different when they line up in Bahrain for the first race of the year.

One feature that can’t be disguised is the reduced floor area required this year to cut the downforce it can generate.

Rule makers decided that change couldn’t wait another season, given the increasing stress being placed on the Pirelli tyres from higher cornering speeds. This was violently demonstrated at the 2020 British Grand Prix, when Carlos Sainz, Valtteri Bottas, and most notoriously Lewis Hamilton, all suffered major tyre failures, the latter limping round the final lap on three wheels to only just beat Max Verstappen to the line.

We spoke to former Mercedes F1 Design Engineer Gabriel Elias and former Mercedes aerodynamicist Miles Jackson, winners of six constructor titles with the team, to talk us through the changes which are coming in this year, how they will affect the cars and the teams, and why some areas are so sensitive for teams.

As Elias says, the alterations will be significant: “If you look at an overhead shots of 2021 cars, the combination of all those those features in the rear floor do a pretty damning job at ripping performance off the car,” he says. “All those things work together.”

2021 F1 Cost Cap

The greatest challenge facing F1 teams this year will in adjusting to the new cost cap, set at $145m (£103m).

It will reduce to $140m (£100m) in 2022 and $130m (£92m) in 2023.

All costs of running the teams are covered in this budget cap with the exception of: marketing costs, driver salaries, the salaries of the three highest earners at each team. The costs of employees’ maternity, paternity and sick leave are also excluded, in addition to the cost of medical benefits and redundancy packages.

In between now and 2024, teams are also allowed to incur up to $45m in ‘capital expenditure’ for things such as factory machinery.

The immediate dilemma is how much of the budget to allocate to next year’s car. Getting ahead for the start of a new set of regulations could offer an advantage for several years but teams won’t want to completely sacrifice the 2021 season.

As explained by the James Allison, Mercedes’ Technical Director, in his own take on the 2021 rules, the cost cap has made the jobs of teams that much harder.

How much can F1 teams use their wind tunnels in 2021?

In another bid to level the playing field, teams are now only allowed to use their wind tunnels for a certain amount of time. Last year’s bottom-placed team in the standings – Williams will be getting the most and Mercedes the least. The amount permitted for others moving on a sliding scale depending on championship position in five per cent increments.

It’s been calculated that Williams will be able to use their wind tunnel roughly 20 per cent more than Mercedes in 2021. Teams are adapting their R&D design processes to offset this as much as possible so that they make the most of every minute their cars are in the wind tunnel.

2021 F1 wind tunnel allowance

What is the 2021 F1 development token system?

As of 2021, teams will be limited by what they can develop on the cars. This has been done in yet another bid to curb costs, and will be regulated by a token system. Teams will only have a certain number of tokens they can use throughout the season.

Whilst the teams are free to develop surface area dynamics throughout 2021, tokens will have to be used to evolve other areas of the car.

The FIA has issued a list of 40 F1 car components that will to have to be ‘frozen’ in their development at a particular point in the season, with teams barred from developing those parts from then onwards. A certain number of components will be frozen from R1 in Bahrain, whilst others will be frozen from R8, currently scheduled to be the French Grand Prix in June.

If a team wants to change any of those parts from that point onwards, it will have to use one of its allocated development tokens.

Different areas of the cars have been given differing development values. For example, bigger parts, such as front and rear suspension, have a value of two tokens.

If a piece only has a value of one token, it can be updated twice throughout the season.

What are the 2021 F1 aerodynamic and floor rule changes?

“The top of the diffuser surface, the inner flicks on the cake tins (brake disc enclosure) on the rear wheels, the floor’s volume, the rearward floor slots, and then the front ones too, have all been reduced or removed,” Elias says. “All those things combined make an absolutely huge difference. The question is how would you recover it?”

Rear Floor

The first significant area addressed is the car’s floor in front of the rear wing and down the side of the car. This baking tray-like structure previously featured various lateral and longitudinal slots.

The slots/inlets helped to generate downforce and, as a result, none are now not permitted in the entire rear section of the floor or down the side of the car.

The floor itself has additionally been pared back also, with two triangular cutouts on each side. This will reduce performance by roughly 1sec per lap.

Jackson details the previous function of the floor and what teams will try do to try and recover performance lost.

“Pre-2021 regulations, different cars would have different rake each creating their own kind of vortex [along the air] along the edge of the floor,” he says.

“The way that you form that vortex – you could break it up by having differentiating edges and things like that – you could change its behaviour and its strength.

“Now that there’s vortices off that, there’s vortices off the edge of the diffuser, when you’re next to the tyre, and also all those details around the tyre strakes in the lower deflector – which is on the wheel. All those vortices interact – all the details that we’ve had on there before were to basically control the vortex.”

Elias is in no doubt about the significant this rule change surrounding the floor is.

“The floor itself adds 60 per cent of the car’s total downforce,” he explains. “It’s the largest contributor and that’s why the rules have taken away floor area, as a way to really hit the teams hard and slow the cars down.”

How can teams recover this lost downforce?

“To recoup that, you got to come up with new ideas,” Jackson says.

“What will start to sprout up at the first races and throughout the year like that will be details, trims and flicks – there’s 50mm above the floor that you can play with.

“Where the floor has been cut away [to reduce downforce], you can do different things – you can notch it, you can kind of put a gurney on the edge, or you could flick it up so it becomes a sharp edge.

“Top floor detail as well as the edge will change a lot through the season – there’s lots of development potential in that area.”

McLaren’s first 2021 car images showed an undetailed, flat floor in front of the rear-wheels, but Jackson says few in the F1 design world have been fooled by this.

“Initially seeing these launches, like with the McLaren reveal, they had a floor and it was flat back there,” he comments. “That’s not what they’re going to drive, you’re not going show up and race with that floor.

“What they’ve shown in their launch videos is basically a dummy floor, because they don’t want to show their hand before the season starts and allow people to copy.”

Mercedes’s Allison admitted in the W12 launch video that its ‘2021’ car also didn’t reveal the full floor detail.

“Down there, there’s a bunch of aerodynamic detail that we’re not quite ready to release to the world – not because it’s not there, but because we don’t want our competitors to see it,” he said.

“We know they’ll be looking, we don’t want them starting to put similar things in their wind tunnels.

“We don’t have to show it yet, so we’re not! It just buys a couple of weeks extra.”

Rear floor load/flex rules

The rules on the amount of load the rear of the floor can take has been tightened up, as has the amount of flex which is allowed. Previously the rear floor was permitted a maximum flex of 10mm. This has now been reduced to 8mm when 500NM of load is applied.

Elias says that for a design engineer such as himself, the reduction of the floor space is a big headache.

“It would present some challenges from a design standpoint, as you’re trying to add structure into the floor but you now have less volume,” he notes. “So that can be very difficult.

“When I was at Mercedes, the questions I would ask would be: ‘How is the floor mounted? What kind of flicks, strakes and little features are there at the ends of the floor, and how are they manufactured?’

“Those kinds of little things actually end up affecting how you know the floor structurally, which is what I cared about.”