F1 teams regularly make stops in about two seconds, so it was quite a shock that Mercedes had to wait for the car to be back at the factory on Tuesday morning to take the wheel off. That was more than 43 hours after the pit stop began.
What went wrong at Mercedes and what is special about the equipment with which the teams break the two-second mark?
In fact, the stops have become so fast, which is why things went so catastrophically wrong for Bottas.
Pit stop details
Mercedes has 20 mechanics on hand at this special stop (below): three for each wheel – one puts the wheel on, one takes the wheel off, one on the wheel cannon, one on each jack in front and behind, one on each spare jack in front and in the back, one on either side of the center of the car to keep it more secure when it is off the ground, one on the hand-cranked brake board, and a main observer.
Lewis Hamilton, Mercedes W12 pit stop
Photo by: Jerry Andre / Motorsport Images
Two more mechanics can be added to this mix, even if a front wing adjustment has to be made (see below), which means that many moving parts and personnel have to be in absolute top position and harmonize perfectly to produce their best hold.
The driver also waits for the wheels and tires to be changed, along with all of the front wing settings, to be lowered from the jacks, and to release the clutch and off you go.
Before that can happen, they have to slow the car down and hit the mark with absolute precision. If the driver is a few centimeters off, it costs time as the mechanics have to reposition themselves to compensate.
Lewis Hamilton, Mercedes W12 pit stop
Photo by: Glenn Dunbar / Motorsport Images
For Mercedes and Bottas, it seems that a slight shift in position was the trigger for the chain of events that led to his death in Monaco when the Finn stood a little behind his main goal.
The mechanics moved around to make up for this but may have accidentally shot up, with the front right wheel mechanic getting too close to the new wheel and the gun operator trying to adjust without the space required.
This resulted in the gun operator having to put the gun down with the handle in an almost horizontal position instead of the 45-60 degree angle normally used (see below).
This meant that not only was the bushing not properly aligned with the nut, but it was also unable to apply the usual force.
Because the gun was attached to the nut at an angle, rather than normally at right angles, the impact between the gun and the nut caused the metal to be worn away.
Valtteri Bottas, Mercedes W12 pit stop
Photo by: Motorsport Images
The fastening tabs of the front wheel nuts were torn off and a visible hint of aluminum dust then emerged from the right of the stage. Despite the gun leader’s valiant efforts to resolve the situation, the die had already been cast – Bottas was out of the running.
During this sequence of events, the gunman also apparently slapped the side of the gun several times.
This wasn’t an angry response, but rather the use of the gun’s directional shuttle which automatically changes direction when the gun is turned.
This allows for faster stopping under normal conditions as the rider has one less physical activity to perform when the old wheels come off and the new ones keep going.
In such a situation, however, they have to manually override the weapon, with the shuttle visible on the replacement cannon behind it (white arrow, above).
The Italian company Paoli supplies the entire starting field and almost all other forms of motorsport with its wheel cannons weighing around 4 kg and around 4000 Nm torque.
But that doesn’t mean they are all the same, because each team not only makes a selection from Paoli’s extensive range, but also adapts them to their needs based on their different equipment choices, ergonomics and most importantly – the endless search for Performance.
Here we look at how each team had their weapons adjusted to better suit them.
Mercedes pit stop detail
Photo by: Steve Etherington / Motorsport Images
MercedesThe wheel gun has a molded top handle, with the mechanics choosing to hold the gun on its side when in use. It still has the more conventional directional shuttle, but its design isn’t entirely standard, with a rear tab and flat edge instead of the domed design seen elsewhere.
Red Bull Pit Crew Wheel Gun Operator
Photo by: Charles Coates / Motorsport Images
Red Bull‘s Wheel Gun Customization clearly has to be at the top of his game as his crew is often able to get the holy grail of now under two seconds. We can see the carbon fairing and light system on top of the gun.
Red Bull Racing wheel pistol in detail
Photo by: Red Bull Content Pool
From the underside we can see how the carbon cladding is shaped and next to the fingers of the mechanics there is not only a button, but also an easily accessible toggle switch that can be activated. Interestingly, they don’t seem to have the traditional shuttle on the gun’s butt either.
Detail of the Ferrari wheel cannon
Photo by: Motorsport Images
Ferrari has a red body on his gun, of course, while he chooses not to have an open molded top handle as the mechanic will instead hold the gun near the collar.
The team also has a carbon cover over the shuttle to prevent the mechanic from accidentally using it while the rocker switch near the mechanic’s finger is likely to be sending a signal to the gantry light system.
Detail of the McLaren wheel pistol
Photo by: Jerry Andre / Motorsport Images
McLarenThe gun has a molded bezel that wraps around the main body of the gun, making it more ergonomic for the user as well as housing the electronic supplements. Also note the manual extractor and spare wheel nut that the mechanics have on hand in case the airlines on their part of the gantry should fail.
Esteban Ocon, Alpine A521 pit stop
Photo by: Glenn Dunbar / Motorsport Images
alpine‘s gun has a custom case rather than a cover, but it is not as heavily contoured as some of its competitors for ergonomic reasons. The shuttle has a large disc at the end so that the mechanic can activate it quickly and without errors.
Aston Martin wheel cannon detail
Photo by: Glenn Dunbar / Motorsport Images
Aston Martin‘s Wheel Gun, perhaps unsurprisingly, is quite similar to Mercedes.
AlphaTauri wheel pistols
Photo by: Jerry Andre / Motorsport Images
AlphaTauri had not covered its replacement guns when this picture was taken, which provides an ideal view of the gun from multiple angles. It exposed the directional shuttle and has a larger disc on the end to activate the direction of the weapon.
Alfa Romeo Racing wheel cannon detail
Photo by: Alfa Romeo
Alfa RomeoThe gun has a section that the mechanic’s hand can bump to get it properly gripped while a conventional shuttle is still in operation. An interesting strapping system is also used by the mechanic on the supporting hand.
George Russell, Williams FW43B pit stop
Photo by: Mark Sutton / Motorsport Images
WilliamsThe weapon does not have the extreme contouring of the handle that can be seen elsewhere in the starting area.
Wheel cannons in the pit lane
Photo by: Mark Sutton / Motorsport Images
Haas takes a relatively simple approach with their wheel pistols, with an ergonomic grip on the barrel for the supporting hand being the only real adjustment.
The caught nut
Formula 1 teams switched to a captive wheel nut system about a decade ago, not only to improve pit stop times, but also to work in conjunction with the restraint systems introduced for safety reasons.
Of course, just like the wheel cannons, each team has its own design, with the noses on the nut designed to work with the socket on their cannons to avoid misalignment.
Mercedes wheel nut comparison
Wheel nuts are considered perishable in many ways as the forces acting on them endanger their integrity, as seen here and as James Vowles explains in the Mercedes-Monaco debriefing video.
“It’s a clout, and what happens is that the mother usually loosens in four or five blows against her, in one pounding action,” he said.
“Well what happened is that we got there at a slight angle. Now when the jack was connected to the nut it was slightly angled relative to it, and as a result of that it was now over instead of spreading the load over the entire nut.” a small section and that tore off the metal cleanly “.
The scarcity of problems at stops suggests that the teams as a whole have a good handle on the design and procedures for a successful stop.
And with equipment both on and off the car falling under the 2021 homologation rules, any lessons Mercedes draws from the situation can only be applied to their hardware for the next season.
However, the small details of what went wrong – including Bottas who is slightly out of position – are taken into account to ensure there is no replay this year.
The post How Bottas’ Monaco F1 pit stop lasted 43 hours first appeared on monter-une-startup.
