Key: F1 teams on target to recover lost downforce in 2021

In a bid to slow cars for this year, and to help put less stress through the tyres, the FIA has introduced a raft of technical changes.

The most obvious is a cut back of the floor area ahead of the rear tyres, but tweaks have also been made to the regulations surrounding brake duct designs and diffusers.

The aim was to reduce downforce by 10% overall, with Mercedes revealing recently that its initial work showed the cut back had taken performance down to 2019 levels.

But, as progress has been made by teams over the winter, Key believes that chunks of the missing downforce have been clawed back by working on the design areas that are still available.

He believes that, by the early stages of the campaign, most teams will be back to the downforce levels they had in 2020.

"It's had the effect of halting the rapid progress that's been going on now with these cars for a long time, and we kind of needed to do that for an extra year of these regs," explained Key about the new rules.

"But there's still a lot of development potential around the rest of the car, and to find, in these changes as well.

"So my guess is that, as we get into the season, most will have recovered everything. Whether it's phase one [race-one spec] or not, it's difficult to say, but I don't think probably 100% yet."

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Key says the specification of car that McLaren has planned for the first race will still be adrift of last year's downforce levels, but he thinks there is plenty of scope to find more gains.

"Our launch spec car is some of that, the race one spec car, which is still in definition at the moment, will be a further chunk of it," he explained.

"So I can't give you a percentage at the moment in terms of where we are actually going to be at race one. But it will be a percentage, rather than 110%, let's say."

While the changes to the car are all at the rear, they have had a knock on impact on other areas too.

The reduction of downforce at the back has, for example, affected the aero balance and will force teams to reduce downforce levels produced at the front of the car to help even things out.

"It's been a real challenge," added Key. "It's required fresh thinking because the geometries imposed by the regulations are unique and not something we've encountered in the past.

"While the changes take downforce away from the rear, it forces you to take some off the front to rebalance the car, so there's been a global reduction in downforce."

But, while downforce levels may recover, lap times will still likely be down thanks to the more robust tyres from Pirelli, with teams expecting them to be around one second per lap slower.