As we watch the drama of an F1 race
unfold, we try to follow the narrative that’s defined by both
strategic and tactical decisions made by the driver and the pitwall.
Many watching at home will second guess decisions made by the team,
on the pitwall and back at the factory, and see them as tactical
rather than strategic, but how we tell the difference? And what do
they see that we don’t?..
Some races are extremely straight
forward and require only strategic thinking but the Hungarian GP
conspired to give us tactical elements too, so, let’s delve into
how the race unfolded and see what was done by the lead pair as they
continue to fight tooth and nail for victories.
The first thing of note was that a wet
qualifying session gave the teams and drivers more dry weather tyres
to choose from and more importantly a free choice on the tyre
compound that they started the race with.
Pirelli supply these infograhics ahead of each race in order that we know how many and what compound of tyres each driver has left in their allocation |
Starting from the front, both Mercedes
drivers opted for the Ultra Soft tyre, the grippiest but lower life
tyre in the range. They did so as the tyre warms up quicker and drops
into the tyres working range more efficiently (90-110o C), meaning
that it should offer more purchase from the grid slot at the start
and then offer more grip in the opening stint of the race. Of course
this comes at the expense of longevity but we’ll see how that plays
out in due course.
Ferrari made their first tactical
decision at the start of the race, when they decided to use different
tyre compounds for their drivers, outfitting Raikkonen (starting P3)
on the Ultra Soft like the Mercedes, whilst Vettel was given the Soft
tyre. The Soft tyre takes longer to warm up and has a higher working
range (105-135o C), which means it degrades slower than the Ultra
soft, giving the team and driver different strategic options overall.
Mercedes stayed on ‘Plan A’ for
Hamilton, running as far as possible on the Ultra Soft (lap 25)
before starting to lose pace relative to the chasing pack, followed
by a long second stint on the Soft, assisted by running in free air,
aside for when lapping traffic.
Raikkonen’s race was one defined by
forceful tactical moves, the first being a relatively short stint on
the Ultra Soft tyre, as the Finn headed for the pitlane at the end of
lap 14. This was clearly a ploy by Ferrari to usurp Bottas and gain
track position with the undercut (the undercut is when you stop
earlier than your rival and use the fresh rubber to maximise laptime
and be ahead of the them after their pitstop).
Raikkonen’s stop was slow though, as
the team had to dislodge some rubber that had built up in one of the
brake ducts (another reason for the early stop, as this may have
pushed temperatures into the critical zones if he continued for too
long).
Shadowing his stop, Valtteri Bottas
stopped on lap 15, even though the team had considered running longer
due to Raikkonen’s slow stop they covered it off, in case they took
had a poor stop. Both drivers took the Soft tyre, which essentially
consigned them to what at the time seemed like a 2-stop strategy,
with the Soft tyre unexpected to make the 56/55 laps needed to make
it to the end of the race.
The resultant pitstops freed Vettel,
who’d been bottlenecked behind the two Finn’s as their tyre
performance waned. Knowing that Vettel needed to run the quicker, but
faster degrading Ultra Soft tyre in his last stint the team were
obviously eager for him to run the Soft as far into the race as was
possible, giving him less time on the quicker tyre but meaning he
could extract his maximum each lap.
As Vettel crossed the line to start lap
32 he was still an adjusted pit stop* ahead of Bottas, whilst
Hamilton, having stopped was 14.502 seconds behind, meaning pit stop
adjusted he was currently around 6 seconds adrift of the Brit.
* The teams monitor the GPS position
of their cars and others and using the adjusted pitstop loss (time it
takes to enter the pitlane, complete an average pitstop (around 2.5
seconds) and return to the track) in order to judge when it’s best
to feed their driver back in, limiting the traffic they’ll have to
encounter as they exit. You’ll often hear this referred to as the
‘Pit Window’, if a driver is referred to as being outside of
another's pit window they will not impact their strategy. However, if
they’re in their window the driver needs to find pace or hope the
other loses some.
This is where the wheels started to
come off the German’s strategy though, as his long stint length
meant he would come across and have to overtake a cluster of
backmarkers, whilst maintaining the kind of pace that would keep
Bottas out of his pit stop window. He actually made light work of it
in the early part, passing Nico Hulkenberg on lap 32, Hartley on lap
33 and as he passed the Ferrari powered Haas of Grosjean on lap 35
the pit stop window had actually increased to just over 25 seconds.
It was Sainz and Ocon then that did the most damage, as they were
busy squabbling with each other.
By the time he’d passed Ocon on lap
38 the gap to Bottas had dropped to 22 seconds and Hamilton had eeked
out his adjusted time to around 11 seconds. Of course, this is not
all traffic related as you must realise that the Mercedes drivers now
had the Soft tyres that were giving more performance than Vettel’s
softer but more worn Softs. This is what we call the crossover
- the point at which the rate of performance of one tyre exceeds the
other.
Seeing the inevitable unfold in front
of them Ferrari deployed another tactic on lap 38, calling in Kimi
Raikkonen for another set of tyres and officially signalling a 2-stop
race for him. What may have seemed odd about this is that they put
the Finn on a set of used Soft tyres, rather than a set of Ultra’s.
However, if we refer to the available sets at the start of the race
(top) we can see that he only had a used set of Ultra Softs left in
his allocation (albeit there is a mistake in that graphic, as the
second set of Soft’s used by Kimi were also used, which is adjusted
in the graphic above)
Putting Raikkonen on a newer set of
tyres would make the Ferrari driver a different prospect on his final
stint. But more importantly it was a ploy to make Mercedes respond
with Bottas, clearing him out of Vettel’s pit window. With a
roughly 20 second pit stop loss it would mean that if Mercedes didn’t
fall for it he’d need to make up that time on track and clear
Bottas who’d be struggling for grip at the end of the race.
Mercedes didn’t bite and played their
own tactical shell game, staying out and opting for track position,
safe in the knowledge that both Ferrari’s would have to make up
time and pass their man on track. The roll of the dice though is that
by the end of the race, Bottas would be on tyres that had done 55
laps, a figure beyond Pirelli’s expectations.
Vettel’s pre stop traffic and pace
loss dramas were compounded when he made his stop on lap 39 for the
Ultra Soft tyre, as he too had a slow pitstop, with the front left
slow to go on his stationary time was 4.2 seconds, making what would
have been a very close battle into turn one an easier proposition for
Bottas, who regained second place.
Vettel decided at this early stage of
his second stint that Hamilton, having checked out at the front, was
now out of reach and he’d instead lay in wait for Bottas’ tyres
to go off and pounce later in the stint.
Mercedes did have a window of
opportunity at the end of lap (51) to pit Bottas to make a second
stop, as a VSC (Virtual Safety Car) period was called to clear
Vandorne’s stricken McLaren. A VSC period offers an interesting
opportunity for the teams and drivers as the time lost in the pit
lane is negated by cars traveling at pitlane speeds out on track*.
This means the only real loss is the
stationary time whilst the car is serviced, which can be made up to
some extent by an aggressive pit entry and exit, as these are
strictly classified as being on track.
Mercedes once again made a tactical
decision, opting to stay out on worn tyres and retain track position.
Had Bottas have pitted they felt they’d relinquish the chance of a
1-2 finish, as they too would be stuck behind the Ferrari pairing of
Vettel and Raikkonen even on much fresher tyres (referring to the
tyre allocation chart they’d have only had worn tyres to choose
from though).
* The caveat here is that if the driver
makes a stop and the VSC period ends during that stop he will
inevitably lose time. As such, Mercedes were monitoring the recovery
of the stricken McLaren and their GPS data to ensure that they
weren’t caught out by this.
As we can see, the wouldn’t have
been, as the McLaren still wasn’t cleared off the track by the time
they passed around and so we were still under a VSC.
The rest as they say is history now, as
the ensuing changes for position were made on track as part of a
tactical battle between the drivers, which of course Bottas lost out
in, having seen his tyres reach their performance cliff.
I hope this article has helped anyone
that has perhaps struggled to understand the difference between
overall race strategy and tactical decisions made during a race, whilst also giving some
insight into adjusted pit stop losses, pit windows and VSC periods
that affect the aforementioned.
As always if you want to support my
work you can do so like my other Patrons for as little as $1 per
month - www.Patreon.com/SomersF1
As a side note an easy way to work out whether a driver is in anothers 'pit window' is to use the driver interval board and work out the culmative gap. Let's say that the pit time loss is a hard 20 seconds it would mean that if Vettel pitted he'd come out 6 or so seconds behind Hamilton, meaning he's in his window (marked in red). Whilst Bottas is 24.491 seconds behind, giving Vettel some margin to stop and remain in front of the Finn (marked in green). You can make this visual assumption very quickly for all drivers up and down the field if you have a rough idea of the pit stop loss.
As a side note an easy way to work out whether a driver is in anothers 'pit window' is to use the driver interval board and work out the culmative gap. Let's say that the pit time loss is a hard 20 seconds it would mean that if Vettel pitted he'd come out 6 or so seconds behind Hamilton, meaning he's in his window (marked in red). Whilst Bottas is 24.491 seconds behind, giving Vettel some margin to stop and remain in front of the Finn (marked in green). You can make this visual assumption very quickly for all drivers up and down the field if you have a rough idea of the pit stop loss.
Excellent writing, as always. Thanks for your data, analysis, and insight.
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