Will Gray

Tech Talk: The importance of pit stops

Will Gray

View photo

.

The high degradation of this year's
Pirelli tyres has seen teams frantically practising their pit techniques - but
how important is a slick stop and how do teams eke out an advantage?

This season has seen a dramatic change
from the one-stop races of last year and so far, aside from Melbourne, where
Sauber's Sergio Perez did manage to go through the race on just two sets of
tyres, the new rubber has forced teams to average between three and four stops
per race.

At the last race in Turkey, winner
Sebastian Vettel took four stops and spent a total of one minute 21.609 seconds
in the pits (between the entry and the exit timing lines). Second-placed Mark
Webber's four stops took just less than three seconds more, with a total of 1:24.401,
and third-placed Fernando Alonso's came in at 1:26.121.

Lewis Hamilton, meanwhile, had one
disastrous stop in which two wheel nuts cross-threaded and he also had to be
held to avoid a collision with Felipe Massa. Instead of his usual stop of
around 21 seconds, it took him 35.688 seconds - and although it ultimately
didn't affect his result, it did demonstrate how much time is easily lost this
way.

Mistakes do happen, and some can be
avoided or engineered out if a team learns from each incident, but it is not
only the big problems that can make a difference and, with close racing, a
regular second or two of time advantage per stop over the opposition during the
course of a race can make all the difference.

A recent study by Auto Moto und Sport
revealed that prior to the Turkish Grand Prix Mercedes were the fastest pit
stop team this season - living up to a reputation they have had since last
year. They had averaged 22.301s per stop with McLaren just 0.082s behind and
Red Bull two tenths slower (although McLaren's average will have been increased
by Hamilton's long stop in Turkey). In contrast, Ferrari were already 1.438s
slower per stop and things did not get any better in Turkey, when Felipe Massa
suffered two costly delays.

Back in 2009, when refuelling was part
of the process, the speed of fuel flow and the amount of fuel required defined
the speed of the stop, which usually took anything between seven and 12
seconds. Now, the stationary time is down to around three or four seconds and
it is so quick every element of the stop must be as slick as possible.

Once the call is given to come in,
before the car even gets to the timing lines it is important to maximise the
speed of the in-lap - which is not easy when a driver is nursing tyres that are
beginning to hit 'the cliff' of degradation that the teams speak about.

He must also maintain entry speed for as
long as possible before having to hit the pit limiter button just ahead of the
timing line - and massive amounts of time can be gained in this area, although
this is not attributed within the actual pit stop times.

The lollipop man and the markings on the
box itself are both crucial to help the driver stop the car precisely where his
team expect it - and if he does not, the whole tyre changing crew have to
shuffle across to get in position before the car can be lifted up by the jack
men, which can cost precious tenths of a second.

The three mechanics operating on each
wheel - one to remove and re-fit the wheel nut with the air gun, one to remove
the old tyre and one to put the pre-warmed new tyre on - practise hard to
ensure they almost move as one, with a fluid motion, because one small fumble
can cause a reactionary knock-on that will add time to each part of the
process.

In this adrenaline-fuelled few seconds,
pressure is huge but it is not just about mental agility and precision
processes, it is also highly physical, whether it's fighting the torque on the
wheel guns or lifting the heavy tyres into place, so intense heat and
exhaustion can also play a part if mechanics are not in good fitness.

In addition to tyre changes, altering
the angle of the front wing, removing debris from sidepods and wiping the
driver's visor are all jobs that can be done, but only if time permits, while
one mechanic will position himself behind the car with an engine starter in
case the driver stalls when trying to leave the pits.

The car is traditionally released by
raising the lollipop, but more and more teams are now developing complicated
electronic lollipops or semi-automated traffic light systems - which when
originally introduced by Ferrari in 2008 caused significant problems but have
now been improved.

This area is just one of several advances
in technology that teams have made to make stops slicker, with others being
quick-release jacks that drop the car back to the ground and cone-shaped wheel
nuts which make it easier for the wheel guns to connect.

Once the stop is complete, the driver then
has the delicate technique of warming up the tyres (which are only part-warmed
by tyre blankets) to get them up to racing temperature and optimum grip levels
- and Felipe Massa's spin in Australian GP qualifying was just one of several
incidents this year that demonstrate what happens a driver fails to do just
that.

Teams put a lot of pre-season time into
rehearsing pit stops and they continue to be an important part of every team's
preparation at each grand prix. And with potentially three or four times the
usual number of stops this season, time in the pits has never been so
important.

View Comments (0)