Saturday during the Styrian Grand Prix weekend
was a wet and stormy day from start to finish.
So much so that Free Practice Three was cancelled
and Formula 1 qualifying was delayed by almost
an hour as we waited for conditions to improve
to a level that allowed competitive laps to
go ahead. Similarly, the Formula 2 waited
and waited for a window to go racing so late
in the day that it had started to get dark.
Now F1 has rain tyres, the drivers are paid
to go racing and know the risks. So why all
the delays? Why do we have safety car starts
or red flag stoppages in the heavy rain? Why
can’t we send them out there and see true
bravery in action, as some are keen to say?
Well, let’s be real about safety for a minute.
While drivers are out to go racing and do
understand motor sports in an inherently risky
activity, they’re not really paid to put
their lives and bodies in overtly outrageous
danger.
We as spectators don’t want to see any death
or serious injury - ideally we want the risks
to be measured in dollars and carbon fibre.
A broken chassis, a DNF and, at worst, a bit
of bruising. It’s not actually fun or good
to see people get broken or killed to our
entertainment.
And of course, the lives we’re trying to
protect also include track staff like marshalls
who have to take on some of the risk of cars
leaving the circuit or spraying broken bits
everywhere.
With that in mind - why is it that the cars
can drive in some rain, but not others? What
makes the difference between acceptable wet
running and weather that needs to stop a session?
Let’s start with emergency medical care.
It is mandatory that during active sessions,
it must be possible to get from the circuit
to a staffed neurosurgery in about twenty
minutes.
If a driver has a serious head or spinal injury
there is a crucial window of time to get them
to specialised medical care.
Some circuits are within twenty minutes driving
distance to a suitable hospital and, if not,
sometimes local hospitals can be temporarily
equipped to be on standby for neurological
emergencies.
If a hospital isn’t reachable quickly enough
by road, then the medical helicopter needs
to make the journey and in order to facilitate
that, the skies must be suitably clear for
safe flight. In heavy weather, the cloud layer
can descend to unsuitably low levels deeming
the helicopter unsafe for take off. In this
case, a session cannot go ahead.
If a neurosurgery is within reach, the track
itself may still be too wet for an F1 session.
See, F1 cars run very low to the ground - the
floor is about 30 - 80 mm above the track-
and heavy rain brings standing water to the
track in puddles or even rivers.
Under these circumstances, the bottom of the
car can slide across the water, lifting the
car and reducing the traction between the
tyres and the track.
Similarly, the tyres themselves can skim over
the surface of standing water instead of reaching
the track.
In these cases, the car essentially floats
above the track, aquaplaning or hydroplaning
in an uncontrollable way, particularly in
braking zones and corners, giving the driver
next to no steering or braking control. This,
of course, leads to potential high speed accidents.
And if a corner is particularly bad, you can
see car after car going off into the same
area which is incredibly dangerous.
Now, of course, the wet and intermediate tyres
are designed to deal with this to some extent
or we wouldn’t be able to go wet weather
racing at all.
The slick tyres have a smooth flat tread that,
as far as standing water is concerned, may
as well be the bottom of a boat.
Wet and intermediate tyres have grooved tread,
so there are islands of rubber designed to
reach the track surface, and grooves designed
to give the water somewhere to go.
By evacuating the water through the grooves
the rest of the tread can draw traction against
the tarmac and control the car.
The intermediate has a higher proportion of
rubber-to-groove than the full wet.
This is because you want as much rubber as
possible drawing grip from the track. The
more you reduce the area of rubber, the quicker
the tyres will overheat. So, if there’s
not much water to displace, don’t go for
the tyres with a lot of missing rubber in
the tread.
You’ll notice the full wets overheat very
very quickly as soon as the track starts to
dry.
The full wets do have an additional advantage
though - they are 10 mm wider in diameter.
This means they raise the whole car 5 mm further
off the ground. This isn’t really that much,
but essentially you are giving the cars extra
ride height for free without having to make
compromises changing the suspension setup.
In a wet quali/dry race scenario as we saw
in Austria, parc fermé rules would mean you’d
want a dry setup for the race so would set
your car up for that - but the wet tyre allows
you some extra ride height on top of that.
Perhaps making them bigger still would give
the wets the operating range for even worse
conditions, but that won’t solve one of
the other problems with heavy rain.
So powerful are Pirelli’s intermediate and
full wet tyres that (at 300kph) they can clear
30 litres of water per second and 80 litres
of water per second respectively.
That’s an obscene amount of liquid. That’s…
X times the speed of me downing this maximum
taste, zero sugar beverage.
All that water has to go somewhere and it’s
right behind the car into chasing traffic
- and that’s added to all the water the
underbody and diffuser sucks off the ground
and throws into the air.
It’s hard to appreciate just how low visibility
gets for a driver as we see an elevated view
from the car’s T-cam. But if we imagine
the layers of spray in front of a chasing
car and lower our viewpoint… it’s clear
just how absurdly difficult to see it can
be.
Anything could be in that spray. Maybe a car,
spun out and stationary across the track.
That’s some of the inherent danger of driving
into blind, thick mist at hundreds of kilometres
an hour. And multiply that blindness if multiple
cars are in close proximity,
So, if enough drivers complain they can’t
see, the race director might deem the track
unsafe and bring it back to safety car running
or stop the race entirely.
Keeping the race going under the safety car
is often preferable as the continued running
of the cars means continued clearing of the
water and keeping the track from building
up too much standing water.
But sometimes things just have to stop. And
we have to wait for a break in the clouds.
