Formula 1 teams are at the limit of pit stop times, reckons Ferrari, which has set the benchmark for tire changes this year.
The Italian team focused hard on improving pit stops over the winter, after ending last year as fourth in the overall rankings behind Red Bull Racing, Mercedes and McLaren. This year, the team has been the fastest overall as an average in the first three races, having delivered the quickest times in the Australian and Chinese Grands Prix.
Its head of trackside operations, Diego Ioverno, thinks that performance – the result of changes to its wheel rim design, wheel nut concept and procedures – has brought the Scuderia at the limit of what is possible.
"In practice, so in a more relaxed environment compared to a race, we have managed to get down to 2.2 seconds at the green light," Ioverno said in Bahrain.
"In the last race we managed to do our best pit stops in 2.6 seconds at the green light. Honestly I think it's difficult to think we can manage 2.2 seconds in the race with a car arriving at 100kph, and with the variable of where the driver stops the car.
"We can say that, as time goes by and with some improvements we have in mind, perhaps we could get down to 2.4sec-2.5sec at the green light, but I repeat: the most important thing is to keep up with a good average, because in the end the importance of a pit stop is to guarantee a fixed time delta to whoever does the strategy, avoiding surprises and the risk of falling behind traffic after a stop."
Ioverno says that as well as copying Mercedes' idea of encased wheel nuts in the rim, Ferrari revised its air guns and changed its wheel nuts, which rotate just three times now to be fully engaged, rather than the more standard six.
"In detail: we have worked on air guns with our suppliers, obviously by making them more powerful, trying to compensate for the limitations added by the federation [the ban on helium]," he said. "We have worked on the car layout, by making fairly strategic and different, risky choices. So we have the captive nut, joint with the rim. We have made some screw thread choices, in order to optimize fastening speed. We have made an important electronic development work on the light system: Ferrari was the first team with a lights system, and I think today we are again the leaders with the light system after having introduced the lights on the jacks.
"The jack operator now doesn't look at the air-gun holder's hands, but he looks at a light that switches on on the trolley when the corner mechanics have finished. So, all these things allow us to minimize the big remaining issues: reaction time, and the precautions needed to be taken to avoid mistakes.
"Clearly I'm just taking about team time with a car standing still under controlled conditions; on top of that there's a big work we are doing with the drivers, also to educate them on the importance of the effect of the car stopping position and method has on the team's confidence in doing its operations – and also how important is the way they approach the pit stop: in the braking, the stopping position and the getting away."