F1’s new cooling vest made a rather inconspicuous race debut at last weekend’s Bahrain GP, with Mercedes’ George Russell having used it during the race. However, Ferrari driver Lewis Hamilton has expressed scepticism about the device, stating that he would “avoid it”.

1. Cooling vest not mandatory for 2025 season
2. System introduced to avoid repeat of 2023 Qatar GP

F1 cooling vest: How does it work?

The cooling vest incorporates 50 metres of tubes through which cooled fluid is circulated. The FIA had originally planned to make its use mandatory when ambient temperatures cross 30.5C, in a bid to avoid a repeat of the 2023 Qatar GP where several drivers were affected by the extreme heat. Logan Sargeant had to withdraw from the race after suffering a heatstroke, while Lance Stroll even briefly passed out.

However, the vest is still optional in 2025, with several drivers expressing concerns about the device being uncomfortable in the tight confines of the cockpit. Given the added weight that comes with wearing the vest, any drivers who opt to not use it need to carry an extra 5kg of ballast to avoid gaining any advantage.

Russell used the cooling vest during Bahrain GP qualifying and race

Hamilton appeared to be surprised when told that Russell used the vest during the Bahrain GP enroute to a second-place finish. “Oh really? I’d be surprised if he did, because you have to add five kilos to the car for it and no one else would,” Hamilton responded while speaking to media, including Autocar India, at the Saudi Arabian GP.

It is understood that Mercedes was able to compensate for the added weight by adjusting the ballast that it normally uses. However, Hamilton has maintained that he’d much rather focus on preparing better before the race.

“I’ve only had maybe two races in my career where it’s been like Malaysia. Our first year at Malaysia, the drinks machine didn’t work. So, I was just dehydrated at the end of the race. And Singapore last year was pretty brutal. But I love that,” the seven-time world champion said.

“We’re supposed to be the highest of the highest in terms of athletes and it needs to be tough. If anything, the cars today are easier to drive than when I started in Formula 1 and they’re a lot heavier. I don’t want to use it if I can avoid it. For me, I want to look at how I can prepare better, how I can use the cooling vest before, how I can pre-cool my body, how to make sure I’m hydrated. That’s a part of the whole process.”

Hamilton added, “I do understand that it’s tough and we don’t want drivers passing out when we go to Qatar, where I think [we had] one race that was extremely hot for the drivers, which I actually crashed out [of], so I didn’t get to do it. I think that it’s good that they’ve got the technology in there, but for me, it’s not what I want to see in my car.”