Mercedes has begun its investigation of the failures which occured on George Russell’s car during last weekend’s Bahrain Grand Prix.
Russell salvaged a second-place finish despite suffering a brake-by-wire failure. He, and other drivers around him, also had to operate their Drag Reduction Systems manually due to a timing loop problem with Russell’s car.
Mercedes said Russell’s technical trouble struck much earlier than it may have appeared from the broadcast of the race. Although the root causes have not yet been identified, the transponder which communicates with Formula One Management’s timing system was “frazzled and charred” after the race.
“Probably from the TV broadcast it sounded like [the fault began in] the final 10 laps,” said the team’s representative Bradley Lord in a video issued by Mercedes. “Actually, it was from about half-distance that we had the first sign of a problem.”
“We’ve just arrived back in the factory with about 10 different suitcases of parts and items that we’re bringing back including a pretty frazzled and sort of charred-looking FOM timing transponder and then some other bits of kit as well related to the brake-by-wire system,” he explained. “So we haven’t got root causes yet.”
Mercedes realised there was a fault with Russell’s transponder when his name suddenly disappeared from second place on their timing screens.
“George’s name just plummeted down the time sheets and we were thinking okay, no, he’s still on track, he’s still talking on the radio so there’s a timing issue here rather than something else.
Advert | Become a RaceFans supporter and
“That also had as a knock-on effect as, if you lose the timing transponder, you lose the part of the car that interacts with the mechanism so for activating DRS, for knowing whether you’re within a second or another car it’s within a second of you. We therefore had to resort to a back-up system. We talked to the FIA, we get permission to do that, and then George was effectively operating the DRS in manual mode.”
Another problem developed on Russell’s car around the same time. “We started to have a separate but parallel problem with the brake-by-wire. That’s the electronics that determine the braking force between front and the rear brakes, but particularly on the rear brakes. There’s a chunk of braking that is done by the MGU-K – the electric motor on the engine – and then a chunk done by the hydraulic braking system.
“When we go into what we call passive mode you’re just relying on those hydraulic brakes. But it changes the car’s behaviour under braking and ultimately it’s very, very difficult to run the car like that because you’re losing a lot of braking force and you ultimately overheat those much smaller hydraulic rear brakes.
“So George was battling with that. We had to do what’s called a default change for him so that he could toggle in and out of that brake-by-wire when it went to passive and put it back in the active mode in those last 10 laps. I think over those last 10 laps he was making between 20 and 30 changes to that setting as he was also driving, hitting his braking points and keeping first Leclerc and then ultimately Lando behind him as well.”
Mercedes grew concerned the timing system problem could have other effects on Russell’s car, such as disabling his steering wheel dash display, but these never materialised. However Russell did activate his DRS by mistake at one point, though the stewards accepted he did not do so deliberately and acted immediately to cancel any advantage he gained.
“We didn’t know what further knock-on effects it might have. The big fear was that it would knock out the dashboard completely so the whole steering wheel display.
Advert | Become a RaceFans supporter and
“If that happens, we can continue driving because there are failsafe and back-up systems in the car that mean we can still change gear, we can still use the DRS and we can still use the radio. We have a back-up radio system in the car that isn’t located on the steering wheel. It’s a button down in the cockpit. That button, as it turns out, is also the manual backup for the DRS if that fails.
“So George was cycling through a practice to go to the back-up radio just in case it was needed, pressed that back-up radio button and inadvertently on the back straight also opened the DRS, because it does the two things at the same time. He realised it within an instant, braked, closed the DRS and continued. That’s when we heard him come on the radio.
“That was what the stewards looked at and investigated and ultimately decided there was no further action for it after the race.”
Russell was “kind of like an acrobat spinning plates” at the end of the race, said Lord. “It’s what made his drive ultimately so impressive not just to have the mental bandwidth to cope with that but also to be doing the driving, making no mistakes, fending off Lando, keeping Leclerc out of striking distance as well. It was a really incredible performance.”
Miss nothing from RaceFans
Get a daily email with all our latest stories – and nothing else. No marketing, no ads. Sign up here:
Advert | Become a RaceFans supporter and
2025 Bahrain Grand Prix
- Russell’s transponder was ‘frazzled and charred’ after Bahrain Grand Prix DRS drama
- “Don’t give me too much now”: Hamilton’s search for speed at Ferrari continues
- “What the hell have you done?” Leclerc shocked by his DRS opening at turn 12
- McLaren makes best start to a season since before its drivers were born
- Norris feels “nowhere near the capability I have” in McLaren’s 2025 car
