Once upon a time, someone on the internet stated that there was nothing wrong with drum brakes on a motorcycle: "Absolutely nothing. Plenty of stopping power and no fluid to change and bleed. Rear drum brake has been put in the same basket as carburetors, ancient technology that deserve ridicule." While we respect the drum brake, and the author's right to his own opinion, we felt that in this 21st century it's important to back up opinions with some facts.
First off, we have to ask, if drum brakes are as good as disk brakes why don't GP bikes or even sport bikes use them? They seem to be exclusive to low and small displacement cruisers and scooters. To answer that we need to understand how brakes work: Brakes use friction to stop the rotation of the wheel. That friction gives off heat. The better your brakes can handle (by this we mean disperse) the generated heat the greater your stopping power.
Try it on a drum brake...
Real life scenario: You're on the highway and need to hammer the brakes from top speed. Once the shoe in your drum brake overheats it will feel weaker and spongier. This is called brake fade. Drum brakes generate heat in an enclosed space, disks brakes flow through air for cooling. Some disk brakes are even made of multiple components ("floating rotors") to better disperse heat and avoid warpage. Disks get contact from two pads generally with multiple calliper pistons and will result in better stopping power, and good disk brakes are far less prone to brake fade than a drum.
Finally, did we mention drum brakes are a royal pain to service? Every time you want to do maintenance (inspection, cleaning, or replacement) of your drum brake you'll need to remove the rear tire off your motorcycle. Every time you adjust your chain you'll need to make sure you properly adjust the drum brake to be realigned. Get too much dust from your shoes and your drum brake will begin squealing. The drum brake on my KYMCO Venox sometimes squeeks if the bike was left in the rain for long periods of time. None of these problems occur with disk brakes, so who needs the hassle for a poorer performer?
I sold my 2004 Suzuki Marauder VZ-800 in favor of an "ancient technology" Harley-Davidson Sportster because the Sporty had a rear disk brake. It's something you should think about from a safety and practical perspective.
Please leave a comment below and check out our safety tips for scooterists and small motorcycles!