the breakdown
- McLaren’s third pedal braked one rear wheel to rotate the car in corners.
- It gave a major lap-time advantage and helped win the 1998 title.
- F1 banned it, but the idea evolved into modern torque-vectoring systems.
The late 1990s were highly innovative and developmental phases for Formula 1. Electronics were advancing, and the rulebook provided plenty of grey areas to exploit, something teams were more than willing to do. Out of this grew one of the championship's most fascinating but short-lived innovations: McLaren's infamous "extra pedal."
It was simple from the outset. Alongside the usual brake and accelerator pedals sat a third pedal, one that allowed them to apply a braking force to a single rear wheel. Prodding that gave the likes of Mika Hakkinen a little extra bite, rotating the car on corner entry.
In theory, it was just braking. But in reality, it was a primitive form of torque vectoring, years before the term became more widely used in the automotive market.
What Did This Extra Pedal Actually Do?
The McLaren system, used between 1997 and 1998, allowed the driver to brake either the left or right rear wheel. By slowing one wheel relative to the other, you could yaw the car more easily into a corner, eliminating understeer, and control torque delivery in the acceleration zone.
This meant the car could be set up generally for less oversteer, something Hakkinen's teammate, David Coulthard, notoriously disliked, but could still neutralize the resulting understeer manually. On its first test, the car went half a second faster per lap. No wonder the team won the 1998 championship.
Importantly, the setup wasn't automated and didn't affect the steering. It was just the driver adjusting the brakes with their feet using skill and judgement. Originally, it was just one side per track, but eventually McLaren added a manual switch within the cockpit so the drivers could change which side braked per corner. The effects were transformative, especially in lower-speed corners.
"We obviously had to check that we were clear on the regulation side," then-McLaren engineer Tim Goss said. "My recollection is that we were confident that it was legal, and we just went for it. In terms of how we got to the assembly, and how we applied the brakes to one rear wheel, it was not much more than an additional pedal and brake master cylinder plumbed in the right way."
Any modern engineer would immediately appreciate it. Formula 1 did not.
Why Formula 1 Shut it Down
Photographer Darren Heath managed to snap a photo of the McLaren with just one brake rotor glowing hot, where it shouldn't have been in use at all.
He and journalist Matt Bishop plotted to get to the bottom of this new phenomenon, eventually managing to grab a photo of the inside of Hakkinen's cockpit before revealing their findings to the world.
While rival teams didn't totally understand what McLaren was doing, they were quick to protest, arguing that it violated the spirit of the regulations. Eventually, F1 classed it as a form of four-wheel steering, banning the system before it was properly developed. The extra pedal disappeared as quickly as it arrived.
Hilariously, teams argued that developing a similar system of their own would be too expensive. According to Goss, it cost £50 to implement.
The Idea Refused to Die
The technology disappeared from F1, but the concept was impossible to ignore. And while it was being experimented with in different forms of motorsport at a similar time as well as a small number of road cars, McLaren's demonstration proved how powerful wheel-by-wheel braking control could be.
Fast-forward a few years, and the technology reared its head in the form of computer-controlled brake-based torque vectoring. Modern stability and traction control systems can reduce understeer, sharpen cornering, and improve balance by automatically braking an inside wheel.
Hot hatches use it to feel playful and agile, and larger SUVs and saloons can use it to disguise their weight and size to a degree.
From here, the concept evolved even further into active-torque-vectoring differentials. Instead of braking, these distribute torque differently from side-to-side. But this still stems from McLaren's original idea: control rotation by managing individual wheel forces.
Why This Matters Beyond Motorsport Trivia
McLaren's "fiddle-brake," as it was later named, is the perfect example of how F1 often acts as a Petri dish—throw something in the mix and see if it grows.
The regulations may have banned this specific solution, but it didn't erase a good idea. Instead, it migrated, became more refined, and arrived in production cars as a form of improving safety. Ironically, it was considered too clever and disruptive for F1, but now drivers barely notice it's there.
