When did cars stop having drum brakes?

The first word your mind associates with brakes is probably disc, right? Disc brakes have been around for decades and have replaced drum brakes on the front wheels of most cars. Their superior stopping power, especially in wet weather, makes them a big step forward in safety.

It might surprise you to learn, then, that many modern cars still have drum brakes — especially on the rear wheels. Why? It turns out there are several reasons.

Manufacturing

Drums are more economical for automobile manufacturers. Disc brakes actually complicate things quite a bit. Using disc brakes on the rear wheels requires automakers to install a separate brake just for parking duty. In such a competitive industry, rear drums are a sound choice for a carmaker’s bottom line.

Safety

Because of their superior heat capacity, discs are arguably safer than drums. But most of the braking power comes from your front brakes. Even in panic stops, your rear brakes get less stress and less heat than your front brakes.

In high-performance cars and vehicles intended for towing, automakers sometimes use disc brakes in both the front and rear. In everyday driving for a typical passenger vehicle, however, there’s no disadvantage to disc brakes in the front and drums in the rear. That’s part of why drum brakes are still a norm in new cars, despite their vintage technology.

Longevity

Because of the lower stress, reduced heat and closed environment that keeps potentially damaging material out of your drum brakes, it’s very likely that your drum brake shoes in the back will last longer than your disc brake pads in the front.

If your car has drum brakes, it is good to get them checked out once in a while. Since a drum is enclosed, there’s nothing you can really eyeball. Unless you have experience doing your own brake jobs, pulling a drum brake apart is something best left to the pros. When you have your tires rotated, it’s a perfect time for a brake inspection and/or brake service.

Advantages of Drums:

• Efficiency:  Greater torque production at a given line pressure for same diameter drum vs. disc.  This is why the disc is almost always larger diameter than the drum it replaces on cars that could have either brake system.  The larger disc diameter is needed for adequate torque production.
• Weight: Drum systems weigh less than comparable disc systems.
• Parking Brake: Drum brakes make a superior park brake due to the wedging action of the shoe against the drum.  Once the park brake is set, any attempt to rotate the wheel causes the drum brake to grip harder (like a wedge type door stop).
• Drag:  Much time is spent designing systems that will pull the pads away from the disc to minimize energy loss due to pad drag on the rotor.   In a drum brake system, springs pull the shoes away from the drum so that, at normal operating temperatures, there is little or no brake drag.  I think I would argue that drums have a higher loss than disc due to how they’re typically adjusted.  But if adjusted correctly, there should be slight drag when cold, but as the drum heats and expands, drag is reduced, or is it negligible?

Check out all the brake system products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for brake maintenance and repairs. For more information on drum brakes, chat with a knowledgeable expert at your local NAPA AUTO PARTS store

Photo courtesy of Wikimedia Commons.

Mike Hagerty View All

Mike Hagerty is an automotive journalist whose work has been featured on radio, TV, in print and online since 1997. He's the Publisher and Editor of MikeHagertyCars.com, and contributes car reviews to the Los Altos Town Crier and losaltosonline.com. Previous outlets have included KFBK and KFBK.com in Sacramento, California, the ABC television affiliates and Hearst-Argyle and Emmis radio stations in Phoenix, Arizona; AAA magazines for Arizona, Oklahoma, Northwest Ohio, South Dakota and the Mountain West and BBCCars.com.

Some people don’t just roll old school — they stop old school, too. Check the specs of some of the most reasonably-priced new cars and you’ll still find drum brakes listed instead of discs, usually on the rear wheels. What’s up with that?

Let’s Start With a Little History

Drum brakes first appeared on a car in 1900. And a couple of very prestigious names were involved along the way. The car sporting those first-gen drums was a Maybach (you might know that as the ultra-lux brand of Mercedes-Benz — and Karl Benz’s wife, Bertha, had invented brake pads 12 years before). Louis Renault patented the brake drum in 1902. His contribution, which allowed the patent, was to change the brake lining to asbestos, to dissipate heat (Bertha’s brake pads were leather). But the modern brake drum was a huge leap for the time — going from a primitive wooden brake to steel and springs that were much more reliable.

The Disc Brake Revolution

Cars pretty much stopped on drums for the next 50 years — until a trio of Jaguars won at Le Mans in 1953. They were equipped with disc brakes, which are less susceptible to fading over repeated use. That meant drivers could brake later going into turns, keeping a higher speed. Soon after, high-end performance cars (largely imports) began using disc brakes and, throughout the 1960s and 70s, more and more conventional domestic cars adopted them too.

Why Drum Brakes Survive

The biggest reason you will find drums on today’s vehicles is cost. It’s a simpler and cheaper design. Maintenance costs are less because drum brakes aren’t as easily corroded as discs. Their closed design keeps debris out, and since they’re most likely your rear brakes, they bear less of the job of stopping your car. A vehicle with discs up front and drums in the rear will probably go a lot longer without a rear brake job than one with discs on all four wheels. They’re also lighter than disc brakes and some hybrid manufacturers have found that having drums on the rear wheels reduce drag and wear from regenerative braking.

Drums also make a superior parking brake. The wedging action of the shoe against the drum is the reason. Once the brake is set, any attempt to move the wheel causes the drum brake to grip harder — kind of like a wedge-shaped doorstop.

Bottom line — if you’re looking at a new car or truck and you see rear drums on the equipment list, don’t worry. You’re not buying an antique. There are some good reasons for that choice, and from a maintenance standpoint, that can benefit you, too.

Check out all the brake system parts available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on drum brakes, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Wikimedia Commons.

Mike Hagerty View All

Mike Hagerty is an automotive journalist whose work has been featured on radio, TV, in print and online since 1997. He's the Publisher and Editor of MikeHagertyCars.com, and contributes car reviews to the Los Altos Town Crier and losaltosonline.com. Previous outlets have included KFBK and KFBK.com in Sacramento, California, the ABC television affiliates and Hearst-Argyle and Emmis radio stations in Phoenix, Arizona; AAA magazines for Arizona, Oklahoma, Northwest Ohio, South Dakota and the Mountain West and BBCCars.com.