How to keep Drum Brakes cool

Al-Fin drums were made by other manufacturers to fit on Triumphs, MGs and other British sports cars. Many Alfa Romeos came with aluminum drums as well. The Datsun 240Z even had them on the back. These can sometimes be modified to fit other special applications. From time to time, new Al-Fins are made up for vintage sports car restorers.

Good Friction
So what else makes a good drum brake? For ultimate stopping power, nothing beats the friction area. While stock drum brakes on low-performance street cars were tiny in diameter and skinny as well, sports models and racers added both diameter and width. As the drum got wider, the pads increased in width and length. In fact, a drum brake has a theoretical edge over a disc brake on initial application due to their increased amount of friction area.


This thinking led Ferrari and others to attempt to develop "super drums" even after discs had taken over most forms of racing. Racing cars used massive aluminum drums with built-in cooling vanes that blew air over and into the drum, sometimes actuated by three separate wheel cylinders. The last frontline road racing car to use drum brakes was the Thomas Cheetah, a wild Chevy-powered racer from 1964 that was shod with massive, but only marginally effective, NASCAR stock car drum brakes.


Stock cars continued to use drums long after road racing cars had shifted over to discs since few American sedans had discs, even on the front, until the late 1960s. Plus, oval racing required very little braking and there was plenty of time for brakes to cool between corners. Even so, by the 1970s disc brakes were standard fare in all forms of racing.