The disc brake is a key example of trickle-down technology in the automotive industry. One that starts at the highest forms of motorsports, and eventually makes its way down to the masses. In the case of disc brakes, it completely revolutionized the way we view cars and driving. OUTRUN seems to think so too, as they’ve produced a stunning documentary on the disc brake’s origin titled The Racers that Stopped the World.
The documentary follows the story of legendary racing driver Sir Stirling Moss and famed Jaguar test driver and engineer Norman Dewis as they were involved with the development of the disc brake. Other notable figures of motorsport in the documentary include Murray Walker, Sir Jackie Stewart, Martin Brundle, Derek Bell, and Andrew Frankel, who recount their personal experiences and insights on the story.
With Moss already cementing himself as the motorsport legend as we have come to know him, he began exploring a new brake technology that Jaguar and Dunlop’s engineers were developing with Dewis. This wasn’t just a minor tweak, but rather they were aiming to turn the whole approach to braking on its head, as things weren’t able to keep up with how quick the cars of the time were becoming.
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They had taken inspiration from Dunlop’s airplane division, which at the time, was starting to toy with the idea of disc brakes. The idea was to use pads clamping down on a rotor instead of pushing out on a drum, with the goal of creating more powerful, consistent brakes that were also more resistant to fade.
Though both disc and drum brakes relied on the same basic principles (friction and heat) to slow a vehicle down, the disk brake’s design was far superior to that of the drum. Since drum brakes were enclosed, heat builds up much quicker, while disc brakes were fully exposed to the outside air, so they allowed for monumentally better cooling. That in turn reduced fade and made for more consistent braking.
The concept itself was quite quite simple, a real example of “Why hasn’t someone done this before?”. However, as it turned out, while the general idea might’ve seemed simple, the hardest part was actually getting it to work and perfecting it to perform reliably.
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They decided to test their concept at the Mille Miglia, figuring all the hard braking on the winding mountainous roads would surely put the new tech through its paces. And they were right, as it helped them greatly during the race. The disc brakes allowed the driver to carry their speed much further into a corner, as well as apply greater braking force as late as possible without worrying about overheating. Eventually, they perfected their technology, and as is with so many other automotive advances, it eventually found its way to the cars driven by everyday people on public roads.
For reasons unknown, it was eight years from the time the documentary was filmed until it was just recently released. It wasn’t until Sir Stirling Moss passed away in April 2020 that the producers of the documentary decided to take the original footage they had and proceeded to complete the film.
You can watch the whole thing for yourself below.