Mechanical Disc Brakes vs Hydraulic Disc Brakes: Everything You Need to Know

The bicycle industry has fully embraced disc brakes on nearly all new bikes but a choice remains: mechanical or hydraulic disc brakes? This modern debate hinges on a rider’s desired amount of performance and value when buying a bike or thinking about an upgrade to their current setup.

The reign of rim brakes has come to an end, especially for off-road riding, but which style of disc brake is right for you? This article lays out the differences between mechanical and hydraulic disc brakes to help you decide which type suits your needs best.

Disc brakes came about as an alternative to traditional rim brakes on a bicycle. Rim brakes work by directly squeezing the rim to slow down the wheel’s rotation. Disc brakes, however, apply force to a metal rotor (or disc) mounted to the wheel’s hub.

Engaging the brake lever near the handlebars causes pistons inside the brake calipers to push the brake pads toward the disc. This process is more efficient than that of rim brakes, providing more powerful and controlled braking performance in all conditions.

Disc brakes have become the preferred choice among all styles of bicycles because of these clear advantages:

• Increased stopping power: Applying force to a central disc instead of along the rim surface allows for stronger braking, allowing for more controlled deceleration and less heat retention on long descents. Rotor size and the number of pistons can also optimize for the desired stopping power.
• Easier lever actuation: Disc brakes require less force when squeezing the brake lever to provide more comfort and precise braking. This reduces the chance of hand fatigue or numbness during extended periods of braking.
• All-weather performance: Rain or shine, disc brakes behave the same so you can ride confidently no matter the weather conditions. Rim brake performance drops off drastically in rainy, snowy, or muddy conditions.

Mechanical disc brakes connect the brake lever to the brake caliper of the bike via a steel cable.

Pulling on the brake lever with your fingers initiates a mechanical movement resulting in the brake pads squeezing the rotor. This cable-actuated process is the same operation on rim brakes and cantilever brakes found on many styles of bikes.

Some sections of the steel cable will be exposed while other sections, where the cable has to make a turn, will run through protective housing. Mechanical disc cables and housing can be routed along the outside of the frame but many modern bikes have internal cable routing inside the frame.

Mechanical disc brakes are reliable components that provide adequate stopping power at a great value. The main benefits of mechanical disc brakes are their cost-effectiveness and simplicity of repair. Mechanical disc brakes can be serviced without the need for many specialized tools or expert knowledge.

Compared to hydraulic disc brakes, however, mechanical setups provide less powerful stopping force. Mechanical disc brakes will also require more frequent maintenance because the steel cable is exposed to the elements and dirt, grime, and rust can build up inside the cable housing.

Mechanical disc brakes are an immediate upgrade compared to rim brakes and are easy to maintain and service. If you frequently ride in wet weather, mechanical disc brakes offer a huge improvement to stopping power during a commute, road ride, or trail adventure.

Mechanical disc brakes were long the standard for all mountain biking disciplines and while premium models now opt for hydraulic disc brakes, many entry-level and recreational bikes still come with reliable mechanical disc brakes.

Hydraulic disc brakes use a sealed fluid system to connect the brake lever to the brake calipers which squeeze the rotor. Instead of a steel cable, a fluid (such as mineral oil) held inside the brake housing operates the hydraulic braking system. This means there are no gaps in the brake housing— the closed system runs all the way from the brake lever to the caliper.

Hydraulic disc brakes have a piston and a master cylinder that contains the brake fluid. Pulling the brake lever moves the piston inside the cylinder, pushing brake fluid through the system. This pressure causes the pistons inside the brake caliper to engage and push the brake pads toward the rotor, slowing down the wheel.

Hydraulic disc brakes are more complicated components with better stopping power than mechanical disc brakes. However, this increase in performance comes with a jump in price. Hydraulic brake levers are much easier to engage with minimal effort, helping to reduce hand fatigue on long descents or demanding terrain. These brakes will also never suffer from cable stretch or fraying over time which is a problem of cable-actuated brakes.

Hydraulic disc brakes require less frequent maintenance because the closed system keeps away dirt and grime. If repairs are needed, however, repairing hydraulic brakes requires a bit more know-how and specialized tools such as a brake-bleeding kit and brake oil. 

Figuring out how to tighten brakes on an electric bike can take some extra practice but the repair can often be done at home.

Hydraulic disc brakes are a great way to enhance the performance of your bike, whether that’s on the road, trail, or anywhere else you love to ride. For example, hydraulic disc brakes are ideal for an electric bike or mountain bike.

The extra weight and faster speeds of electric bikes mean more force is required to bring the e-bike to a controlled stop. Having an idea of how much an electric bike weighsdemonstrates the need for heavy-duty disc brakes. Trail, downhill, and electric mountain bike riders prefer the performance edge of hydraulic brakes when navigating steep descents and technical terrain.

The principle difference between mechanical and hydraulic disc brakes lies in how they transfer force from the brake lever to the brake disc rotor. This difference in design has consequences on the brakes’ performance, longevity, servicing, and cost.

Whether you’re building up your dream bike or deciding between similar models, you should figure out which brake system best matches your needs. The final decision ultimately comes down to how you want to balance performance gains with your budget.

Consider these factors when picking between mechanical and hydraulic disc brakes:

• Performance vs. recreation: If you are a road racer or mountain biker, hydraulic disc brakes are more powerful and precise. Mechanical disc brakes do the job just fine for casual riders who don’t require such high-caliber components.
• Riding style: Hydraulic brakes offer more responsive and controlled stopping power which is ideal for faster-paced riders who demand a lot from their brakes.
• Sticking to your budget: Mechanical disc brakes are less expensive than hydraulic brakes and are easier and cheaper to repair when the time comes.

Yes, bikes that run mechanical disc brakes can be upgraded to have hydraulic brakes. Parts like brake levers can’t be retrofitted across different brake systems. You’ll need to purchase the complete hydraulic brakeset including new calipers, housing, and levers, and replace all the old mechanical brake parts. For example, riders can upgrade a used electric mountain bikeby installing better-quality hydraulic brakes and enjoy an immediate performance boost.

Hydraulic brakes can significantly improve the overall feel of your bike, but the value of the investment depends on your riding needs. Competitive road cyclists and mountain bikers swear by the performance advantages of hydraulic brakes that not only allow for more precise braking but also withstand the heavy forces from traveling at such high speeds.

If you are a recreational cyclist who doesn’t ride that fast, hydraulic brakes probably won’t make too much of a difference. Hydraulic brakes are recommended for heavy electric bikes since stronger brakes can handle the extra heft and power of modern e-bikes.

Mechanical and hydraulic disc brakes have clear advantages over traditional rim brakes but, when compared against each other, the outright winner isn’t so obvious. Mechanical brakes are easier to service and offer great value for recreational riders who don’t frequently reach high speeds. Hydraulic brakes are the premium choice for performance-oriented riders, especially suited to e-bikes, racing road bikes, and mountain bikes. Whatever disc brake system you choose, though, you can confidently leave rim brakes in the dust!