New Documentary Shows How Racer Sir Stirling Moss Developed Disc Brakes

Illustration for article titled New Documentary Shows How Racer Sir Stirling Moss Developed Disc Brakes
Screenshot: OUTRUN

Motorsport has served as a proving ground for loads of new technologies that eventually make their way into the auto industry’s consumer cars, and a new documentary shows exactly how that happened with disc brakes. And yes, it involves legendary racer Sir Stirling Moss and Jaguar test driver and engineer Norman Dewis.


This documentary, The Racers That Stopped the World, was filmed about eight years ago by OUTRUN but has only just been released. The production company decided that, after Moss died in April 2020, it was time to create a beautiful movie.

Seriously. It’s exceptional. If you’re not wiping away tears by the end, you may need to check your tear ducts.

As the story of the disc brake goes, Norman Dewis was working with the concept alongside Jaguar and Dunlop in an attempt to develop a braking system that could better keep up with the growing demands of speed. Dunlop was playing with the disc brake concept for its airplanes, but no one had yet implemented it in a car.

Basically, everyone was using drum brakes, which enclosed heat and resulted in sketchy braking after the brakes started to fade. Disc brakes are more exposed to the air, so they cool better and therefore function better. Sounds simple, right?

Well, the process of designing and then testing was certainly a challenge, and that’s where Moss came in. He tried the concept out at the Mille Miglia, the thinking there being that there’s no better place to test a new bit of tech than windy roads. It turned out to work beautifully. And the rest is history.

And Moss isn’t the only legendary driver to feature in this documentary. Murray Walker, Sir Jackie Stewart, Martin Brundle, and Derek Bell all weigh in on the story. It’s worth the half hour watch.

Weekends at Jalopnik. Managing editor at A Girl's Guide to Cars. Lead IndyCar writer and assistant editor at Frontstretch. Novelist. Motorsport fanatic.


the 1969 Dodge Charger Guy

Given how prevalent disc brakes have been for decades, where even el-cheapo cars come with at least discs up front (where 70% of your braking force is effective); I’d bet no more than 5% of the Jalopnik readership has even ridden in a car with manual drum brakes. (“Manual” defined it’s still hydraulic, but it’s your leg muscle bringing two tons of metal to a stop.)

As I’ve warned in posts and to friends thinking about getting their own old muscle car, if it still has manual drums, then do not buy it. The car WILL KILL YOU. I am absolutely serious as I’m trying to save you from yourself.

The Charger had the weak 10x2.5 manual drums when I bought it and I kept it that way for years. Then I upgraded to 11x3 drums in the front and even that small improvement was eye-opening. Now I’ve got slotted, cross-drilled discs all the way around and the Charger has new car stopping power. So sweet.

Keep in mind how back in the day everyone had awful drums and knew how to compensate—big gap to the car in front, know how to pump them when panic-stopping. Now thanks to ABS and ESC nanny gadgets, basically none of you have the skills to bring one of these old cars to a stop when in an ohshit! situation without wrecking. So DON’T buy an old muscle car. Or if you must have one, at least get it upgraded to discs so your wife isn’t a widow before the first weekend of ownership is over.