Do E-Bikes Require Disc Brakes? Pros and Cons Explained

Although electric bikes are not classified as motor vehicles (provided they are 750w and below), many reach speeds between 20 and 28mph. This relatively quick pace means that electric bikes require sufficient braking capabilities. With the various brakes available, we must ask, “Do e-bikes need disc brakes, or are rim brakes sufficient?”

Although not mandatory, disc brakes are a tremendous benefit to electric bikes. Disc brakes offer superior stopping power, essential for heavier electric bikes traveling at greater speeds. If possible, aim for disc brakes. Equally important is a killswitch which cuts the motor when you decelerate.

While disc brakes are at the pinnacle of electric bike technology and are on most mid to top-range models, some electric bikes sport other brake types. So what sets disc brakes apart as superior? Which electric bikes need them? Which don’t? And what are the pros and cons of disc brakes?

Why Should Electric Bikes Use Disc Brakes?

All brakes transform kinetic energy (movement) into heat through friction. Disc brakes are better at dispersing heat (spreading out), so they do not wear as quickly as other brakes. They do not slip as easily in wet conditions.

Their design gives disc brakes better-stopping power than other brakes. Electric bikes (e-bikes) travel at greater speeds (and with more weight) than other bikes (think of cargo e-bikes and mountain e-bikes).

Thanks to old Newton’s second law of motion, we know that force equals mass (the weight of the e-bike, rider, and accessories) multiplied by acceleration (how fast you’re going).

For example, a 176 lb person riding a 20 lb e-bike traveling at 20 mph produces a force of roughly 3920 newtons (N). To stop, you need an equal but opposing force.

You’ll need roughly 700N of braking force (per wheel), which the brakes produce by pushing against the rim/disc. As the brakes slow the e-bike’s wheels, gravity causes friction between the ground and the tires, eventually slowing the e-bike to a stop.

Increasing the rotor’s size improves the stopping power of a disc brake (better heat distribution and more surface area for the calipers and brake pads).

Disc brakes come in two varieties:

Mechanical Disc Brakes

Otherwise known as cable disc brakes, when the rider pulls the brake lever, it tightens a cable that connects to the brake unit. Calipers squeeze brake pads against the rotor disc, causing the e-bike to stop through friction.

These cheaper disc brakes are often on low to mid-range e-bikes.

Hydraulic Disk Brakes

While these brakes also use the friction of brake pads on the rotor to slow and stop an e-bike, they work with hydraulic fluid. When the rider depresses (pulls) the brake lever, a piston pushes the fluid through the hose and against other pistons in the brake unit.

The second set of pistons engages the pads against the rotor disc.

While more expensive, these disk brakes perform better and provide a smoother experience. The cables in mechanical disc brakes are prone to stretching, which reduces their efficiency over time.

Hydraulic disk brakes are superior in comfort and stopping power; however, cable-operated disk brakes work well and are on many more affordable disc brake e-bikes.

Brakes aside, an e-bike should switch its motor off when you pull the brakes. Otherwise, you’re fighting against the motor while trying to brake.

Disc Brakes Vs. Other Electric Bike Brakes

The three most commonly used brakes include caliper rim, disc, and V-brakes. Each brake type has several advantages and disadvantages and is better in some situations.

Below, the table compares some of the features of these brakes.

Specification

Disc brakes

Caliper rim brakes

V-brakes

Braking Mechanism

Pads squeeze a rotor disc attached to the wheel when acted on by pistons or a cable.

A cable pulls the single-caliper arm mounted on the bike’s frame, which squeezes the brake pads onto the rim.

V-brakes differ from caliper brakes in that they have two separate “arms” connected by a cable, which joins the cable from the level.

When pulled, these arms move together to squeeze the rim, like caliper brakes.

These brakes require pulling more cable than caliper brakes.

Stopping power

The bigger the rotor disc, the greater the stopping power.

These have the strongest stopping power and are the least likely to lock.

These brakes have the least stopping power of the three. Although comparable and sufficient (especially in dry conditions), these brakes fall short in wet and muddy conditions.

The longer the arms, the more stopping power the brakes have. These robust brakes are stronger than caliper rim brakes but are less consistent than disc brakes.

They also lock a bit easier than disc brakes.

Stopping force

Friction (squeezing a rotor disc)

Friction (squeezing the rim)

Friction (squeezing the rim)

Weather limitations

Works well in wet and dry conditions

May slip in wet and muddy conditions

It may slip in wet conditions but perform better than caliper brakes.

Weight

These brakes are the heaviest and weigh roughly 2 lbs (including rotors, calipers, and extra cable length/hydraulics).

These are the lightest brakes, making them ideal for road racing. They are roughly 0.9 lbs (they are around 1 lb lighter than discs)

While lighter than disc brakes, they are heavier than caliper brakes as they are more robust.

V-brakes weigh roughly 1.12 lbs (they are around 0.88 lbs lighter than discs)

Maintenance

Although disc rotors and pads wear, a benefit is they don’t wear the rims like the other brakes.

Overall, minimal maintenance. You’ll adjust the cable occasionally, replacing worn pads and hydraulic fluid.

Pads are more specialized and expensive.

These brakes need regular cleaning and lubrication on slide pins. Periodic pad changes and cable adjustments.

Replacement pads are cheap and widespread.

Rim brakes wear down the bike rim, which eventually needs replacing.

Pad changing is more complicated than disc brakes, as the pads need to align properly.

However, aligning these brakes is easier than calipers.

Their pads also wear unevenly and need periodic adjustments.

Parts are easier to find and inexpensive.

Aesthetics

Modern, high-tech, sleek (especially with hydraulic systems); visible disc rotor. However, many “traditionalist” cyclists may view them as clunky.

Classic, traditional, minimalistic; visible mechanism. Almost synonymous with bikes and thus feels “right.” They are also less noticeable than disc brakes.

Rugged, utilitarian; visible long arms reaching down to the rim. Although becoming rare, these brakes have a traditional look about them. They are more noticeable than calipers but less than disc brakes.

Situations and use

Where stopping power is essential.

Including: downhill mountain biking, mountain biking, cargo e-bikes, and more powerful e-bikes.

Where stopping power is required but on a tighter budget.

These brakes are aerodynamic but limit the tire width.

Including: cheaper mountain e-bikes and road e-bikes.

On mountain bikes (not electric) and touring bikes.

These strong brakes allow for wider tires. They were immensely popular during the 20th century.

These brakes have less clearance than caliper brakes.

Cost

These are the most expensive and range from $50 to $500 for a set, depending on the system.

These are significantly cheaper than disc brakes and range from $80 to $90 for a great set.

These are mostly outdated and are cheaper than caliper rim brakes.

They cost roughly $30 to $50 a set.

Which Electric Bikes Need Disc Brakes?

Disc brakes are essential for any performance-related electric bikes. Riders should invest in e-bikes with disc brakes when speed and maximum control are requirements.

Most mountain e-bikes are fitted with disc brakes due to the nature of where they ride and their increased weight (they require sturdier frames).

The inclusion of disc brakes is one of the factors that can contribute to the cost of electric mountain bikes.

Likewise, faster-traveling e-bikes should have disc brakes to ensure maximum stopping power (over the shortest distance).

Which Electric Bikes Don’t Need Disc Brakes?

While road/commuting electric bikes benefit substantially from disc brakes, they are some examples of e-bikes that can “get away with” using rim brakes. Provided they are not designed for high speeds or are too heavy.

Bikes that travel along the road, where there is (generally) enough space for braking and where the speed is not particularly high, are the best suited to rim brakes.

These brakes are frequently used on “budget-friendly” e-bikes. However, buyers can usually upgrade to disc brakes when possible.

Just like the need for disc brakes, the need for suspension in e-bikes depends on how and where you'll be using the bike.

The Benefits And Drawbacks Of Disc Brakes On Electric Bikes

Disc brakes bring several benefits to riders; however, they are not without their limitations and drawbacks.

The Pros Of Electric Bike Disk Brakes

  • Better stopping power, which means better control for heavier e-bikes
  • While most disc brakes have two pistons, specially-made hydraulic disc brakes have four pistons (for improved braking force), which is essential for extreme riding conditions
  • These brakes work better in wet conditions than rim brakes
  • Disc brakes are less likely to deteriorate from wear and tear than rim brakes
  • These brakes don’t damage your wheels’ rims during use
  • Disc brakes accommodate larger e-bike tires (like fat tire e-bikes). You can also change the disc rotor size, so if you find that you lack braking power, you can upgrade

The Cons Of Electric Bike Disk Brakes

  • These brakes become hot during (intensive) braking, which reduces their efficiency, and could potentially warp (bend) the steel. This overheating is usually in cheaper quality disc brakes constructed of a single piece of steel
  • Disc brakes make e-bikes more expensive. A rotor disc and calipers (and a hydraulic system in some situations) push the price of the e-bike up, which might be out of some rider’s budgets
  • There are several disc pad designs; you must choose the matching pads when replacing them. The same goes for the hydraulic brake fluid (different brands)
  • Although less likely to wear, you’ll have to replace the brake pads if they are exposed to oil or other contaminants
  • Disc brakes are heavier than rim brakes, which increases the e-bike’s total weight

Conclusion

Electric bikes are relatively heavy and fast-traveling vehicles that greatly benefit from disc brakes. Disc brakes improve the stopping power of e-bikes by dissipating heat better than rim brakes. These brakes also provide a more consistent braking experience, even in wet conditions. However, disc brakes are more expensive, increasing an e-bike’s price.

While disc brakes can provide considerable stopping power for e-bikes, especially in challenging conditions, they're just one of many possible upgrades. If you're curious about other ways to enhance your e-bike's performance or comfort, check out our guide on what to upgrade on your e-bike.

Author

  • Miles Baxter

    Miles Baxter is an engineer with a longstanding love for bicycles, sparked by winning a mountain bike in a childhood lottery. Balancing a keen interest in mechanics with the thrill of biking, his career is a testament to the art of turning wheels and gears into adventures.

    Baxter Miles