How to lighten heavy mechanical brakes.

Posted at: Feb. 13, 2022

The weight of the brakes not only affects the braking power, but also creates a significant impact on fatigue during the ride. In this article, we'll take a look at how mechanical brakes work and how you can lighten the weight of heavy brakes.

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First, let’s learn how mechanical bicycle brakes work

How mechanical brakes work

The brakes of bicycles, including road bikes, are composed of three parts: the lever, which is operated by hand, the brake itself, and the wire that connects the two.

The mechanism of a mechanical brake is very simple: when you hold the lever, the wire connected to the brake is pulled, and the pulled brake closes to apply the braking force.

In other words, the braking force of the brakes is the force that closes the brakes, but it is the force of the rider’s grip on the lever that closes the brakes themselves, so the key to “light but firm stopping braking” is how efficiently this force can be used.

Braking force of mechanical brakes

It is often said that “higher grade brakes stop better,” but the braking force of brakes is almost entirely determined by the strength of the human grip.

This is especially true in the case of rim and caliper brakes, where the wheel rim is clamped by the shoes, and the stronger the grip, the more firmly the brakes stop. Of course, the quality and maintenance of the shoes also play a role, but it is also important to know how to transmit the human grip force.

For example, if a person with the same grip strength upgrades to a higher grade brake, he or she will feel that the brake stops much better. In other words, the brakes work better.

In other words, “brakes work well” is almost the same as “brakes are light”.

Why do mechanical brakes get heavy?

So, why do mechanical brakes become heavy? In the case of mechanical brakes, there is only one factor: the “resistance force” that interferes with the transmission of grip force.

With mechanical brakes, three types of resistance forces are generated.

  1. force to return the lever
  2. force to rub the wire
  3. force to return the brake

These are the causes of the weight of the brake.

If these resistance forces were zero, the brakes would be surprisingly light to pull. However, “lever return” and “brake return force” are mechanisms to maintain the non-breaking state (lever and brakes open), so if the resistance forces here are zero, the pulled brakes will not be able to be restored If the resistance here is zero, it will not be possible to restore the pulled brake.

How to Lighten Heavy Mechanical Brakes

Once you understand how the brakes work, you can then improve the heavy parts, which will inevitably make the brakes lighter.

1. Fixing wire routing

Routing has no small effect on the weight of the brakes.

First, let’s review the routing, which does not require any additional cost.

It is easy to think that it is just routing, but in the case of a complete car, the outer wires are often stretched especially long, which may cause unnecessary resistance.

Since the wire “creates resistance where it bends,” improve the routing so that it is as straight as possible.

Just by reviewing the routing, the brakes may become lighter.

2. Check the condition of the wires and replace them if necessary

Once the routing is done, it is time to check the condition of the wires.

In the case of external frames, water or sand may have gotten inside the outer wires, and this may have caused the inner wires to rust.

Rust creates a great deal of resistance, so replace the inner wire that seems to be quite rusty.

At this time, it is better to inject a chemical that reduces resistance into the outer wire.

3. Change the brakes

If this does not change the weight of the brakes, the first thing to suspect is the brakes themselves.

Since the brakes are spring-loaded back, the stronger the force to bend the spring, the heavier the braking will be. Some professional mechanics can adjust the brake spring by themselves.

Even with higher grade brakes, if there is mud or foreign matter caught in the brakes, it will create resistance to brake movement.

If the brake is still heavy, you can assume that the brake itself is heavy.

To find out if the brake body is heavy, try closing the brake body with your hand. For road bikes, the higher grade brakes, such as Shimano’s DURA-ACE and ULTEGRA, have a lighter spring and can be closed with a little pressure from your fingers.

On the other hand, the unmarked brakes used in entry-level models, for example, should require a lot of force to close.

If the brakes are quite heavy when you try to close them by hand, the reason for the heavy braking is that the brake return force is too strong, so replacing the brakes with those of a higher grade will dramatically lighten the braking.

People often say, “Let’s just get 105 brakes,” but the brakes of 105 and above open firmly but can be closed easily with your fingers. So, “lighter brakes => better brakes”.

4. Replace the brake lever last

If replacing the brakes does not improve the situation, the last thing to consider is replacing the brake levers.

“If you want to reduce the resistance to pull, why not the lever first?” But the return force of the brake lever is not as great as you might think. To test this, remove the inner brake wire clamp and pull the brake lever. You’ll be surprised at how sluggish it is.

Mechanical brakes have a simple structure, so the brake lever is “simply pulling the wire. Therefore, the return force of the lever when the brake is not being pulled is the resistance that the brake lever is generating.

The reason why you should consider replacing the brake lever is because of the ease of grip, which is different from the resistance. The harder we grip something, the less effort we can put into it, so if the brake lever is hard to grip, it means that we cannot exert our grip force properly.

Therefore, when considering replacing the brake lever, rather than trying to reduce the resistance of the brake lever, ask yourself, “Isn’t the current brake lever difficult to grip? Will it be easier to grip if I replace it? Rather than reducing the resistance of the brake lever.

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