Trailer Drum Brakes vs. Disc Brakes: Making the Decision

Whether you're adding brakes onto your trailer, replacing old ones, or upgrading for better stopping power, we're here to walk you through everything you need to know to get the job done right.

Having brakes on your trailer is a must. Almost every state requires brakes on trailers of a certain size in order for them to be street legal, and there are plenty of good reasons for that. In addition to keeping you and others on the road safe, brakes help keep your cargo safe by providing an improved, more controlled ride. Getting the best possible braking setup for your trailer will also help eliminate wear and tear on both your trailer and your tow vehicle, saving you a lot of money in the long run.

What are the differences between drum and disc brakes? Which setup is best for heavy-duty towing? Are disc brakes worth the money? What do I need to install hydraulic brakes? You might be asking some, if not all of these questions.

Today we’ll answer those questions (and more) so you can finally cross one thing off that never-ending list of decisions to make: deciding what type of trailer brakes are best for you.

Jump to:

Drum Brake Overview
Electric Drum vs Hydraulic Drum Brakes
Can You Use Electric Brakes on a Boat Trailer?
Disc Brake Overview
Electric Over Hydraulic Brakes
Drum vs Disc: Which One Should You Get?

Drum Brakes

Highlights: Low initial cost, greater chance of brake fade, more maintenance than disc brakes

In order to know which type is better for you, it helps to have some general knowledge of trailer brakes and how they work.

Drum brakes come in two styles: electric and hydraulic. Electric drum brakes use an electric signal sent from a brake controller in your vehicle to tell the brakes to slow down, and hydraulic drum brakes use brake fluid sent from the trailer's actuator to tell the brakes to slow down. Even though electric and hydraulic drum brake assemblies use different methods to activate the brakes, the way they function is very similar.

How do Drum Brakes Work?

Both types of drum brakes feature an enclosed cylindrical assembly with several smaller components. One important component both types have in common are brake shoes on the outside of the drum. The brake shoes are lined with automotive-grade friction material. When the brake is applied, different forces (depending on which type of brake you have) move the shoes outward where they press against the inside of the drum to create friction. This friction stops the wheels from turning and allows your trailer to brake when your vehicle does.

Quality of Drum Brakes

Drum brakes are a much older technology than disc brakes, and they also come with some disadvantages.

For one, drum brakes experience brake fade more often than disc brakes. Brake fade is when the brakes lose their effectiveness and stopping power after sustained or repeated use in a short time period. Brake fade is caused by heat build-up, and can happen when going down a steep descent, or while in high speed/load conditions. Brake fade is more prominent in drum brakes because the enclosed design causes heat to build up much quicker than in disc brakes. Overheating can cause drum distortions, which leads to vibration when braking.

Drum brakes also retain more water than disc brakes, which causes corrosion. If you're using drum brakes on a boat trailer that is frequently submerged, keep in mind that you'll have to replace the brakes more frequently than you would if you went with disc brakes.

Cost and Maintenance

Don’t get me wrong, drum brakes are still a very popular and widely loved solution. You might be partial to the fact that drum brakes are considerably less expensive than disc brakes, mainly because it costs less to make drum brakes and they are a bit lighter.

If you're adding electric drum brakes to your trailer, you'll probably end up spending—including the brake controller and wiring—between $300 (low end) to $1,200 (high end) for a complete setup for one axle. To add hydraulic drum brakes to your trailer, an entire setup for one axle—including the actuator and hydraulic lines—typically costs anywhere from $500 to $1,600.

Drum brakes are more affordable to purchase outright than disc brakes (you’ll find out how much those cost later on), but they take a lot more time, effort, and money to maintain and repair. Even with the convenient open design of drum brakes, there’s a lot more effort involved in replacing any little part of the brake assembly. Even replacing a little spring requires removing the wheel, hub, cap, and seal—and most likely re-packing the bearings while you’re at it.

Electric drum brakes

This is for you if: You want a cost-effective option with advanced user control

This is not for you if: You have a boat trailer and are concerned about corrosion

Electric drum brakes are activated by an electric signal that comes from a brake controller in your tow vehicle.

The brake controller senses when you press the brake pedal and sends a signal through your trailer’s wiring to the brakes. This signal energizes the brake magnet, which then sticks to the armature (magnetic) surface of the hub. The rotating hub pulls the magnet, which causes the actuating arm to engage, which then causes the brake shoes expand and squeeze against the hub, creating the friction needed for braking.

For the majority of people, price will be the reason they choose electric drum brakes. These are the most cost-effective option, being even less expensive than hydraulic drum brakes because they don't require you to run hydraulic lines or have a surge brake actuator.

But arguably the best characteristic of electric brakes is the advanced user control. Electric brakes give you the ability to dial up or down the sensitivity of your brake controller to have your brakes engage when and how you want. The manual override function allows you to activate the brakes independently of the vehicle—which can be helpful with controlling sway and traveling down steep inclines.

Of course, this same level of user control can be achieved with hydraulic brakes by using an electric-over-hydraulic actuator along with your electric brake controller. But that brings us back to a huge advantage of electric brakes: no hydraulic lines and fittings are needed. The wiring setup for electric brakes is pretty simple and a lot less expensive than dealing with hydraulic lines.

For electric brakes, both your tow vehicle and your trailer will need a 7-way trailer connector to supply the wiring needed to send and receive the brake signals. (Click here to find out how to wire a 7-way trailer plug.) You'll also need a breakaway kit which will activate the trailer brakes in case it disconnects during travel. Lastly, you'll need that important brake controller mentioned above to activate and control your trailer brakes.

To read more about what you’ll need to add electric brakes to your trailer, click here.

Can You Use Electric Brakes on a Boat Trailer?

Electric brakes are not the most ideal brake type for a boat trailer. Even with the uneasy idea of mixing water and electricity, some boaters still opt for electric brakes to outfit their trailer. Why? Mainly because of their lower price and great user control. But we recommend just spending the extra money and opting for a hydraulic setup in this case.

However, if you're set on using electric brakes, make sure to disconnect them before backing your boat trailer into the water (because of, you know, that whole water and electricity thing mentioned above). We also recommend spraying off the brakes with fresh water after boating to minimize corrosion buildup. Keep in mind that fully submerging the brakes in the water will eventually corrode and wear them down much quicker than on a non-boat trailer.

Hydraulic drum brakes

This is for you if: You want a cost-effective option compatible with any tow vehicle

This is not for you if: You want a very easy installation with low-maintenance

Hydraulic drum brakes use natural momentum and brake fluid, rather than an electrical current, to activate the brakes.

The most crucial part of a hydraulic brake setup is the actuator. When you press the brake pedal, the momentum from stopping your vehicle compresses the actuator which triggers the master cylinder to force brake fluid back through the hydraulic lines and down to the brakes. From there, the fluid enters the wheel cylinder and pushes the servo(s) out to expand the shoes against the drum, creating the friction needed to stop the trailer.

If you want drum brakes on your boat trailer, we recommend hydraulic drum brakes over electric. One reason being nothing has to be disconnected when backing the trailer into the water, unlike electric brakes. Hydraulic drum brakes also have the option of being more corrosion-resistant than electric brakes. They can feature details such as a galvanized coating and stainless-steel hardware to help them last longer with the frequent exposure to water.

Unlike electric drum brakes, hydraulic drum brakes don't require any sort of in-vehicle device like a brake controller to power them, which is a huge advantage if you own a trailer rental company or tow your trailer with several different vehicles. All the components of a hydraulic drum brake setup is on the trailer itself so you can hook it up to any vehicle equipped to tow with no problems.

One challenge with hydraulic brakes’ operation is that when you reverse, the pressure of your vehicle against the trailer also sends brake fluid to the brakes. To avoid the brakes locking up when reversing, the brakes either need to be free-backing or you must have an actuator with a reverse lockout (we recommend an electric lockout over a manual lockout as you won’t have to get out of your vehicle to flip a switch).

To read more about what you’ll need to add hydraulic drum brakes to your trailer, click here.

Disc Brakes

This is for you if: You'll pay whatever it costs to have the most powerful, efficient, and low-maintenance braking option

This is not for you if: You don't want to spend a lot of money upfront and don't want to worry about running or bleeding brake lines

Hydraulic, or surge, disc brakes are becoming a strong contender for any type of trailer. They're efficient, reliable, and easy to operate and maintain. They have fewer moving parts than drum brakes and are self-adjusting, which means they don't require as much maintenance (we're talking hardly any).

How do Disc Brakes Work?

Disc brakes are composed of a hub and rotor (often a 1-piece design), a caliper, and a mounting bracket. The caliper, which is positioned around the hub and rotor, includes a piston and brake pads, one pad on each side of the rotor.

When you activate your truck brakes, the force of your vehicle against the actuator creates hydraulic pressure inside the master cylinder in the actuator, just like with hydraulic drum brakes. This pressure sends brake fluid through the brake line to the piston in the caliper. The piston extends and pushes the backing plate of the inner brake pad, which then squeezes the rotor. The friction created by the brake pads squeezing the rotor slows down the trailer.

Disc brakes are known for providing more consistent stopping, and more stopping power in general, than drum brakes. This means they reduce your stopping distance so you'll be less likely to jackknife or collide with another vehicle should you have to slam on your brakes. And because of their design, disc brakes are very well vented. This is why they don't experience brake fade as often as drum brakes, if at all.

These bad boys are definitely our preferred choice. Because of their self-contained design, disc brakes don't retain any excess water, which not only prevents corrosion, but also makes them function a lot better when wet. This makes them a very popular choice for frequent boaters. However, the price often stops people from making the decision to go with disc brakes over drum. Even though disc brakes don't require as much maintenance, they're considerably more expensive to purchase outright.

Cost and Maintenance

For a single-axle trailer, a complete disc brake setup can cost anywhere from $675 to $2,175, depending on several factors including the quality and quantity of parts you choose.

Keep in mind, even though you're dropping more cash at the beginning, disc brakes will most likely save you money in the long run because maintenance costs are typically minimal. Disc brakes tend to last longer and function better overall, which means less wear and tear on your trailer, cargo, and tow vehicle.

Drum to Disc Brake Conversion

If you're switching from hydraulic drum brakes to hydraulic disc brakes, you'll need to purchase the disc brakes themselves (hub and rotor), then replace your hydraulic drum brake actuator with a hydraulic disc brake actuator. (You won't be able to use your current drum brake actuator because disc brakes require a higher psi of 1,600.)

If switching from electric drum brakes to disc brakes, you'll still need to get the hub/rotor assemblies and a disc brake actuator. Because you didn't have hydraulic brakes previously, you'll also need to purchase a brake line kit with additoinal lines, which lets you run brake fluid from the actuator to the brakes. These kits vary based on the length of hose you'll need and how many axles your trailer has (or how many axles you're using brakes on). If you’re adding disc brakes to an idler axle, you can get kits with slip-on rotors so you don’t have to replace your hubs. To see more articles on how to change your trailer brakes, click here.

Electric Over Hydraulic Brakes

If you like the complete control and quick response time of electric brakes, but you want the stopping power and efficiency of disc brakes, there’s another option for you. Getting an electric over hydraulic setup will allow you to have the best of both worlds.

To achieve this ultimate setup, you'll need a few things. First, you’ll need hydraulic brakes. Most people with this setup opt for disc brakes (which is also the option we prefer) because of the advantages mentioned above (more stopping power, less brake fade, better corrosion resistance).

You’ll also need an electric over hydraulic actuator. This special type of actuator will receive the brake signal from your electric brake controller and send brake fluid to the hydraulic brakes. This means you’ll also need an electric-over-hydraulic-compatible brake controller to control the aggressiveness and intensity of the hydraulic brakes. A breakaway kit is another essential you’ll need, which activates the trailer brakes if your trailer gets disconnected.

Electric over hydraulic actuator.

Drum vs. Disc: Which One Should You Get?

Get Electric Drum Brakes If:

If you want as much control over your trailer as possible when towing, electric brakes are the perfect option for you. By using an electric brake controller, you can adjust braking aggressiveness, set a delay if needed, and use the manual override. This complete control makes electric brakes a very popular option for many types of trailers.

Electric brakes are especially popular for fifth wheel and gooseneck trailers because there’s no standard tongue coupler, which makes it impossible to have a surge brake actuator. This leaves you to go with either electric brakes or an EOH setup. But with the tight space of a fifth wheel or gooseneck, many opt for electric brakes because it can be tough to find a spot to mount the EOH actuator.

If you don't want to spend more money up front than you have to, electric brakes are the solution for you. While they require you to purchase more parts for the vehicle side (brake controller, wiring, adapters, etc.), the upfront cost of electric brakes is still a lot less than a complete disc brake setup.

Electric drum brakes are also much easier to install than hydraulic brakes. Because you won’t have to worry about running and bleeding hydraulic lines, all you’ll have to do is run a few wires and you‘re up and towing!

Get Hydraulic Drum Brakes If:

Hydraulic drum brakes are for the person who wants the best of both worlds. These brakes are inexpensive to purchase outright and they don't cause concern for mixing water and electricity.

Hydraulic drum brakes can be better equipped for water submersion than electric drum brakes. So, if you have a boat trailer and don’t want to invest in disc brakes, these are a solution for you. They have the option of a galvanized coating, sometimes with stainless steel hardware. However, they still won’t hold up to saltwater as well as disc brakes. There are a lot of small parts that can rust and need to be replaced, and drum brakes don’t have any ventilation to rid them of water like disc brakes.

If you own a rental company (or you just lend your trailer to friends and family often), hydraulic drum brakes are a great solution for you. Any vehicle equipped to tow can tow a trailer with hydraulic drum brakes because you won’t have to worry about brake controller compatibility.

As mentioned above, if you go this route you'll need to make sure that either your actuator has a reverse lockout or you purchase free-backing brakes so that you can reverse your trailer without the brakes locking up.

Get Disc Brakes If:

If you want the most powerful and efficient brake setup that money can buy, disc brakes are for you. They're perfect for hardcore boaters, and those who live in places with a lot of salt on the roads, because of their low-maintenance and superior rust-resistant design. Disc brakes’ performance in wet conditions is unmatched; the vented rotors get rid of any excess water which will give you powerful and reliable braking.

Disc brakes aren't only great for boaters, they're also impressive on heavy fifth wheels (with an EOH setup) and travel trailers. This is especially true if you don't want to mess with trailer wiring and a brake controller. Even though their response time isn’t as quick as electric brakes (we’re talking milliseconds here), they do the best job at stopping that heavy RV in time to avoid a collision, even in high speeds. This makes them far safer than drum brakes, especially for heavy trailers and highway driving.

If you ever plan to tow in the mountains, you’re going to want disc brakes on your trailer. When going down steep hills, disc brakes won't overheat as quickly as drum brakes, so they won't experience brake fade as often either.

If you've read this far, you probably know a lot more than you wanted to about trailer brakes. But now that you know how each type works, along with the pros and cons of each, you should have a pretty good idea of which one is better suited for you and your trailer.

Still have questions?

Give our experts a call at 800-298-8924, or contact us online. We're happy to assist any way we can!

About the Author

My journey with etrailer started in Customer Service, where I went through months of product training to make sure that I had all of the knowledge I needed to help our neighbors find a solution to any situation. I helped them with technical questions, troubleshooting, product information, and anything else they needed. Since it has always been my passion to write and express myself through words, I made the transition over to the content side of the website so I could combine my product knowledge and passion for writing.

In order to make sure that I am giving you the most accurate, current information, I am constantly doing research and talking with people who are doing what I am writing about every day. I am constantly striving to find out what questions you are asking, and to give you an answer to every one of those questions, plus answers to questions you haven't even asked yet - yes, I'm that good. Plus, I am constantly getting hands-on training with our vendors and asking them all of the hard questions, that way you can have all of the information you need before making a decision.