Recently, we’ve been receiving a lot of questions about disc brakes.
Since these systems come with both advantages and disadvantages, it’s necessary to choose the best option for your specific use case.
In this series, I’d like to cover the "ins and outs" of disc brakes, such as "how should I choose one?" and "how do they actually differ from one another?"
We’ll start with the basics, so please stick with me.
First, let's start with the simplest question: "What is a disc brake?"
A disc brake is a braking system used to stop a moving bicycle.
It looks something like this.
There is a metal disc called a rotor attached to the wheel, and a main body called a caliper.
This design is used in cars, motorcycles, and trains, and I believe it is the most widely adopted type of brake.
The adoption rate for sports bicycles has been increasing every year, and to put it conservatively, it is now used on more than half of all complete bikes.
So, what are the pros and cons?
Pros
・Less reduction in braking power compared to rim brakes even in poor weather conditions
・Higher braking power itself, which reduces fatigue during long rides
・Eliminates the need for the rim (a wheel component) to handle braking tasks
・Prevents tire sidewalls from getting dirty when riding in the rain
Cons
・Heavier weight compared to rim brakes
・Somewhat more expensive
・Often requires proprietary, specialized parts
・Standards and specifications can be complex and confusing
That’s a quick summary.
With so many downsides, including the "weight increase" which is the sworn enemy of bicycles, why does its adoption continue to rise?
In my opinion, it is because of the following two particularly noteworthy advantages:
・Less reduction in braking power compared to rim brakes even in poor weather conditions
・Eliminates the need for the rim (a wheel component) to handle braking tasks
Because of these two advantages, one can easily overlook the other disadvantages.
Let’s dig a little deeper.
・Less reduction in braking power compared to rim brakes even in poor weather conditions
I consider this to be the biggest advantage.
Rim brakes work by pressing brake pads (rubber) against the sidewalls of the rim, so the exposed brake pads are highly susceptible to negative impacts from weather and road conditions like rain and mud.
In comparison, disc brakes stop by pressing pads installed inside a caliper against a disc rotor, which is a separate component from the rim.
This part is further away from the tires and is less affected by road conditions.
The second advantage, **"eliminating the need for the rim (a wheel component) to handle braking tasks,"** might be a bit harder to understand, but it is important.
Due to their structure, the rims used in rim brakes must have a section to receive the brake pads, which limits the flexibility of their design.
Furthermore, the section that receives the pads requires enough strength to handle the braking force, which impacts the rest of the wheel structure.
However, with a disc-brake-specific rim, the rim is freed from the job of braking and can focus entirely on forming the wheel and rotating.
This increases design freedom, allowing for shapes with better aerodynamics and shock distribution.
The improvements in riding performance brought about by these two advantages are things that cannot be achieved with rim brakes, and they provide a strong enough reason to adopt disc brakes.
Well, this has already become quite a long post.
I’ll leave the specifications and standards required for bicycles when adopting disc brakes for the next time.
See you again soon.