A Formula One race can be won or lost in a single pit stop. For a few brief moments every Grand Prix, the race becomes about more than just a driver and his car – twenty mechanics move with perfect choreography, crowding around the impossibly small car to change a set of tyres in as little time as possible. For the pit crews, who practise this manoeuvre thousands of times in a season, a delay of one tenth of a second feels like hours.

Since mid-race refuelling was banned in 2010, the margins of error for pit crews have become increasingly narrower. "Last year, and the year before, we were really impressed by a sub-three second pit stop and now we’re looking at sub-two seconds," says Gemma Fisher, a human performance specialist for Williams Martini Racing. In the 2016 season, Fisher’s team was the fastest pit crew in fourteen races and in the Baku Grand Prix they equalled the record for the fastest in-race pit stop ever, clocking in at just 1.92 seconds.

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Once her team has finished doing a set of practice pit stops, Fisher analyses every aspect of the manoeuvre, searching for areas where time savings could be made. "We break what happens down into every single aspect and look for areas where we can improve – that’s everything from the people using the kit, down to the ergonomics of the kit we’re using," she says.

Nothing is left to chance – even the seating location of every crew member in the garage is mapped out in advance in order to minimise collisions and make sure each mechanic knows exactly the route they’ll take out onto the pit lane.

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A mistake in the garage could be devastating. When Red Bull driver Daniel Ricciardo entered the pits in pole position at the Monaco Grand Prix in May 2016, his team didn’t have his tyres ready in time. Ricciardo sat in the pit lane as seconds ticked by and his lead went to Lewis Hamilton. Hamilton went on to win the race, and was just pipped to the 2016 Championship by teammate Nico Rosberg, while Ricciardo was left complaining he’d been ‘screwed’ by his team.

Williams Martini Racing


One way to avoid situations like the one Riccardio found himself in, Fisher explains, is to drill pit stops until they become second nature. "The skill needs to be on a level where it's autonomous – it needs to be learned as a matter of course," she says. Her team will train for unlikely situations that might put a less prepared crew off their kilter; a last-minute change of tyre type or nose change. "If you train to the most complex scenarios in your practice then hopefully, on race day, the pit stop is relatively straightforward," she continues. In perfect conditions, she says her crew can perform an entire pit stop in just 1.6 seconds.

A phenomenal amount of activity goes on in those brief seconds. The car pulls into the pit and comes to a complete stop, the front and rear jacks are fitted and lifted, the gunner loosens the wheel nuts, the first tyre carrier takes away the worn tyre and the second replaces it with a fresh tyre, the gunner tightens the wheel nuts, the jacks drop and the driver pulls away. Each of these stages has to be completed before the next can begin. There is no room for mistakes.

When you’ve only got two seconds to play with, squeezing every millisecond counts. The average human reaction time is around 200 milliseconds, exactly the same length of time the gunners need to spend loosening or tightening the wheel nuts. Too tight means wasting time undoing them at the next pit stop while too loose could mean losing a wheel while the car is on the track. "Within a normal human reaction time [the gunner] has to not only do the operation but decide that he's achieved it, and come off," says Steve Nielsen, Williams’ sporting manager.

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Felipe Massa pulls in for a pit stop at the Spanish Grand Prix Williams Martini Racing


Achieving these near-superhuman reaction times requires constant practice but drivers can also do their bit to make their pit crew’s jobs as smooth as possible. "The pit stop begins before the car stops – if the driver comes in with a jerky motion the guys on the guns can't get to the nuts. If he comes in in a very predictable straight line and slows down a uniform manner the nuts are undone before he actually stops," Nielsen says.

After every practice, Nielsen, Fisher and the Williams team trawl through video footage and data from the car and equipment to look for areas where they can shave fractions of a second off of their time. "We can tell how long someone's been gunning on, or gunning off, or how long the jacks have been raised," says Fisher. In the early years of F1, gunners would raise their hands to indicate to the jack man they’d tightened the nuts on the wheel, but automation has cut out the time it takes for the jack man to register four crew members with their hands in the air. Now, when the last gunner presses the completion switch on their gun, the jacks automatically drop and the car can leave as soon as a green light indicates it's safe.

Williams Martini Racing

But Williams isn’t just crunching data to make its equipment more sophisticated. Last season the team began using biometrics to assess how pit crews perform under pressure with experts Avanade. Four members of the Williams pit crew wore a range of sensors over the 2016 season in order to, Fisher hopes, make training more specific to each crew member’s needs. "We’re looking at heart rate variability, recovery times, breathing rate and estimated core temperature," Fisher says.

This information, paired with data from video footage and equipment, will shed light on what each crew member requires to perform at their very best. Some seem to thrive on the stress of a pit stop, but for others that pressure can be detrimental to their performance. The more Williams understands about its pit crew’s psychological state, the more it can do to help crew members use that race-day stress to their advantage. "We need adrenaline, that's great, but if they're operating on the limit they have no capacity to take in any more information or react to what's going on," Fisher says.

Williams driver Felipe Massa retired from F1 at the end of the 2016 season only to return to replace teammate Valtteri Bottas who made a surprise move to Mercedes Williams Martini Racing


This winter, the Williams team went through the biometric data to start considering how to supplement the intense physical training that pit crews go through to prepare for races. "We look at all the aspects of fitness that we need for a pit stop. We look at what that individual might be doing - everything from explosive power to hand-eye coordination, agility, speed, reaction time, flexibility," Fisher says. But their pre-season training for 2017 also included more of a focus on remaining cool under pressure and using adrenaline to their advantage.

So what’s the limit for a super-fast pit stop? In 2011, the two-second pit stop barrier seemed insurmountable, but Williams – and Red Bull before it – has shown that laser-focused training will cause pit stop times to tumble. Rule changes for the 2017 season, however, promise to change the dynamics of the pit stop once again. Fatter, heavier tyres will mean pit crews will have to focus their training on strength and tweaking their approach to suit the new rubber. For Fisher, biometric data may well prove critical in helping the Williams crew adjust to the new kit and stay on pole position in the pit crew rankings.

"We want to make sure we stay ahead next year, it's going to present a lot of different challenges, especially with the size of the wheels and therefore the added weight," she says. "There will be physical challenges so we need to make sure the guys can perform and keep them in the best shape possible."