If you’re looking to buy an electric bike, the quality of the brakes may not be the top of your priorities. You may be more concerned with the power of the motor, or the battery capacity for example. However, the quality and type of brakes on your electric bike is worth considering. Especially since they are arguably the most important safety feature of the bike.
The type of brake you will find on an electric bike will mostly either be a rim brake or a disc brake. This is the same for regular bikes as well, by the way. Also rim brakes and disc brakes are either mechanical or hydraulic actuated. Whichever of these brake types you decide for your electric bike, will determine the bike’s stopping performance. This is as well as the amount of maintenance your brakes will need. These factors will likely determine your choice of brake type for your electric bike.
Here in this article, I discuss how rim and disc brakes compare, with regard to electric bikes. I discuss the advantages and disadvantages, features and considerations for both. So this should help you decide on which type of brakes you want for your electric bike. By the way, I talk about hydraulic vs mechanical actuated brakes in another article.
Why Brakes are Especially Important on Electric Bikes
As mentioned above, brakes are arguably the most important safety feature of the bike. This is particularly the case with electric bikes, due to the extra weight they carry (because of the motor and battery). This is also due to the higher speeds they can go as well. Therefore, electric bikes need more stopping power, for them to stop over the same distance as a regular bike. So this means it is especially important to have high quality brakes on electric brakes.
How Disc Brakes work
Disc brakes work by there being a disc (known as a rotor) at the center of the wheel which has pads on each side of it. When the brake levers are pressed, these pads are then pressed against this disc. This creates friction which then slows the bike down.
How Rim Brakes Work
These brakes work by pads (attached to calipers) that clamp down on both sides of the wheel rim. Again, this creates friction, which then causes the bike to slow down. These pads also clamp down by the way, when the rider presses the brake levers. So as you may gather, rim brakes and disc brakes both essentially work the same way. The difference is that disc brakes have pads clamping down on a rotor and rim brakes have pads clamping down on the wheel rims.
Disc Brake Considerations
More Stopping Power
Disc brakes provide more stopping power than rim brakes. This in itself is as good a reason as any to opt for this type of brake for your electric bike. Remembering that good stopping power is particularly important on electric bikes.
Many heavier cyclists opt for electric bikes, due to their weight making it harder for them to ride regular bikes. So the extra weight of both the rider and the bike can again increase the need for more stopping power. Similarly you may want as much stopping power as you can get if you have an electric cargo bike. The more cargo you’re carrying, the longer the bike will take to stop, due to the extra weight. By the way, electric versions of cargo bikes are very popular. This is due to the electric power making it easier to carry the extra weight.
Better Braking Control
Disc brakes give you more feedback when you’re pressing the levers than rim brakes. This means that when compared to rim brakes, the stopping force of disc brakes is much more consistent with the amount of pressure you’re applying to the levers. As a result, disc brakes allow you to more precisely determine the amount of force needed when braking.
You may particularly appreciate this aspect if you’re riding on off-road trails and in urban environments. Both environments where you’re likely to be speeding up and then slowing down, at varying amounts. This is due to constant hazards occurring. Having the better feedback of disc brakes can make you feel safer. This is as well as instilling more confidence whilst riding. The reason being, that you’re more likely to know what response you’re going to get when you engage your brakes.
Better in Harsher Conditions
Disc brakes work much better than rim brakes in wet, muddy and snowy conditions. Remember that rim brakes make contact with the wheel. So with rim brakes, if the wheel is wet, or has dirt, mud, or snow attached, then this can compromise the pads contact with the wheel. As a result, this will reduce the stopping power. Depending on the quality of the brake pads though, this may not necessarily reduce the stopping power significantly. However, when comparing the 2 brake types in less than ideal conditions, disc brakes will always have the edge.
Remember the brake pads on disc brakes are coming into contact with rotors at the center of the wheel. As these rotors are not contacting the ground, they will have less mud, water and debris on them, than the wheels. This is why disc brakes work better than rim brakes in harsh conditions, as the pads have a cleaner contact on the surface they’re connecting to. So if you’re planning on doing a lot of off-road riding or live in a rainy part of the world, disc brakes are the way to go.
Better for Weak Hands
Remember that disc brakes provide more stopping power than rim brakes. So this means that with disc brakes, you can apply less pressure (when pressing the brake levers) than if you have rim brakes, to get the same stopping distance. You may have small hands, lack grip strength (maybe due to injury, or being of advancing years), or have arthritis in your hands. In which case, you may find it tricky to apply a lot of pressure on the brake levers. Therefore disc brakes can be a very good option for you here. Having arthritis, or being of advancing years, may be the very reason why you’re looking to have an electric bike. This is due to these factors possibly making riding a regular bike difficult.
Don’t Wear the Wheels
As disc brakes do not come into contact with the wheels like rim brakes do, they are not enhancing the wear of your wheels. Even though the rotors will wear, they tend to be easier and cheaper to replace than wheels. Rotors tend to be built to last as well.
Disc Brakes are Heavier
Disc brakes are heavier than rim brakes and so they add more weight to the bike. Give or take, disc brakes are around 500 grams/1 pound heavier than rim brakes. You may not be that concerned with that amount of extra weight though. This could be due to the extra weight of the battery and motor that electric bikes carry already. Any extra weight may therefore not make too much of a difference. The extra boost you get from electric bikes, will negate any loss in speed from having extra weight anyway.
Disc brakes can make the handling of the bike feel sluggish. This is due to the extra weight they add to the wheels. They may not necessarily always make the handling feel very sluggish though. Nevertheless, they can create a more sluggish feel, when compared to having rim brakes.
This can be more of an issue if you have a front hub motor on your electric bike. Front hub motors do have a habit of making turning and the general handling of the electric bike feel sluggish. Again, due to the extra weight they are adding to the front wheel. So with regard to handling, if you do have disc brakes on your electric bike, it’s better to have a rear hub motor. Or even better further still, opt for a mid drive motor. You will have much better weight distribution throughout the electric bike, if you have a mid drive motor and disc brakes.
Trickier to Adjust Whilst out on a Ride
When compared to rim brakes, disc brakes are trickier to maintain on the go. Sometimes whilst riding, the brake pads may start rubbing, due to that they may have become out of alignment. This will reduce the stopping power. Also disc brake pads can cause a very loud squeaking noise when they are out of alignment. You can always stop the bike and re-align the brake pads, if you know how. However, re-aligning disc brake pads tends to be a bit more of a faff than re-aligning rim brake pads. This is due to the fact that disc brakes need to be more finely tuned. Whereas with rim brakes, it’s easier to just shift the calipers.
This video shows how to adjust disc brakes, for whenever you need to.
You can enhance disc brakes stopping power further by having bigger rotors. Remembering that stopping power is particularly important for electric bikes, due to their weight and speeds they can go. Larger rotors create more friction, which in turn means more stopping power. Disc brake rotors come in the below sizes. By the way, when a rotor’s size is specified, it is the rotor’s diameter in millimeters.
The extra stopping power you get from having larger rotors, also helps if you have weak grip strength or arthritis. You can apply less pressure when pressing the brake lever with a large rotor, to get the same stopping distance as applying more pressure with a smaller rotor.
By the way, it’s more relevant to have a large rotor on the front wheel, rather than the rear wheel. This is due to physics determining that your weight shifts forwards when you brake. Therefore most of your braking power is coming from the front. So if you did want to strike a balance between having strong stopping power, whilst saving as much weight as possible, you could have a large rotor on the front wheel and a smaller rotor on the rear wheel. Again, bike weight might not be an issue for you though. So if your budget allows, then it doesn’t hurt to have large rotors on both wheels.
Having large disc brake rotors on your electric bike can be a cheaper alternative than having hydraulic brakes, to get good stopping power.
Rim Bake Considerations
Rim Brakes are Lighter
As mentioned before, rim brakes are usually around 500 grams/1 pound lighter than disc brakes. A lot of cyclists appreciate this aspect, as the lighter the bike, the faster it is. Also less weight makes the bike easier to ride, especially uphills. However, again, the electric boost you get from electric bikes counters any weight constraints whilst riding. Having said that though, the lighter your electric bike, the bigger the range you’ll get from the battery. This is due to the heavier the electric bike, the more of a draw from the battery it’ll be whilst riding.
Also with regard to weight, the lighter the bike, the easier it is to balance when you’re at a stop. This is say if you’re at a stop light, or you’ve stopped for a water break, for example. So for this reason you may prefer rim brakes to minimize as much weight on the bike as possible. This is especially where I have mentioned before that electric bikes are already heavy due to the battery and motor. Also you may be a light person, who may find a heavy bike difficult to balance at a stop.
Easier to Maintain
Rim brakes are much easier to maintain than disc brakes. When it comes to replacing the pads on rim brakes, you just slide the pad out and put a new one in. Simple as that. By the way, pads do wear, so you would expect to replace them after a while.
Rim brakes are also easier to adjust when they are out of alignment than disc brakes. Below is a simple instruction of how you would generally expect to adjust rim brakes.
- Just use an allen key to loosen the screw in the back of the fork.
- Adjust the position of the caliper.
- Tighten the screw back up again.
The great thing about adjusting rim brakes with the above instruction, is that anyone can do it. All in all, rim brakes offer simplicity when it comes to maintaining them.
Easier to Transport
As mentioned before, rim brakes add less weight to the bike than disc brakes. The less weight the bike carries the easier it is to pick it up and carry, as and when needed. The stronger you are though, the less of an issue this will be for you.
People who like to transport their bikes in the trunk of their car on holidays or to trails, sometimes like to take the wheels off. This makes it easier to fit their bike in the trunk. However, it is harder to take the wheels off the bike if you have disc brakes. It’s certainly more of a faff. This is due to having to contend with the rotor on the wheel. If your electric bike has a hub motor, then taking the wheels off for transportation is a no go anyway. Certainly at least on the wheel that the hub motor is situated on.
So if you’re someone who likes to transport your electric bike in the car with the wheels off, then having a mid drive motor with rim brakes is the way to go.
Furthermore, whilst the bike is in transit, rim brakes are less likely to get damaged than disc brakes. The disc brake rotors can get knocked or bent during transit, which can cause damage, or them to be out of alignment. You can remove the rotors during transit to prevent this though. However, this is another thing to do and takes up time. Essentially the fewer parts a braking system has, the fewer parts there is to worry about during transit. So again, rim brakes lend themselves to being easier for transporting.
Easier to Change Wheel/Tire
If your bike has rim brakes, then it’s much easier to replace a wheel or a tire, than if you have disc brakes. This is because with rim brakes you don’t have that rotor at the center of the wheel, like you do with disc brakes. You may be someone who likes to replace your tires and/or wheels often, for different types of cycling. If so, then rim brakes can be a more convenient option. This is also more convenient if you ever incur a flat tire.
Less Tire Clearance
Because tires have to pass through rim brake calipers, this limits the width of the tires you can have with rim brakes. This is due to the fact that the tire can be no wider than the amount of clearance the caliper allows for. To an extent, this counters where I have said it is easier to change tires with rim brakes. If you like to use different tires for different conditions, then you may not be able to have as wide a tire as you like sometimes, if you have rim brakes.
If you have a bike with wide tires and rim brakes, then you will need long reach calipers. As the name suggests, these calipers allow for more tire clearance. So if you want rim brakes and you like switching your tires out for different ride types, then long reach calipers are an ideal option. By the way, it’s advisable to have long reach calipers in the first place, rather than upgrade to them later. This is due to the fact that to have long reach calipers, you need a frame that can accommodate them. This article An Ode to Long-Reach Brakes talks further about long reach calipers.
Remember again, if you like to sometimes change your tires on your electric bike, then it’s a lot easier to do so if you have a mid drive motor.
Because rim brakes are lighter and easier to travel with and maintain, they offer more simplicity overall than disc brakes. This in itself is a reason why many people prefer rim brakes to disc brakes. This is even though disc brakes offer better stopping power. After all, rim brakes still provide good stopping power, even though disc brakes have the edge. This is especially if they are well maintained, aligned correctly and you have good quality/condition pads.
You may have a strong grip to apply a good amount of pressure on the brake levers. Essentially be able to comfortably slam on those brakes. Also you may live in a dry, sunny part of the world where it doesn’t rain often. You may even be someone who doesn’t really ever cycle quickly and prefers to cruise along at a leisurely pace. So if any of these apply to you, then you may feel the stopping power of rim brakes is enough for you. Therefore, you may not want the extra weight and less simplicity of disc brakes, if you feel rim brakes already do a good enough job.
Ultimately, when it comes to rim brakes or disc brakes for your electric bike, neither type is better than the other. It’s all down to personal preference. You may prefer the simplicity of rim brakes, or the better stopping power of disc brakes. What you could find is yourself trading off a disadvantage of one of these brake types, against an advantage of it.
For example, you may like to sometimes change your tires for different riding conditions. However, you may prefer to minimize weight on your wheels, to reduce a sluggish riding feel. Nevertheless, you may opt for disc brakes, so that you have more freedom with the width of tires you can have. This is even though they would add more weight to your wheels.
Either way, both types of brakes will give you good stopping power. This is as long as they’re made to a good quality and maintained well.