Brakes are broadly divided into two types: "rim brakes" and "disc brakes."

Both have their pros and cons, so overall, neither is unilaterally superior.

Rim brakes are often used on cross bikes and road bikes, so here we will limit our explanation to rim brakes.

There are different types of rim brakes

Even within rim brakes, there are various types such as "caliper brakes," "V-brakes," "cantilever brakes," "center-pull brakes," "U-brakes," and "direct-mount brakes."

• Caliper brakes

There is an axle, and the brake arms are arranged to cross each other left and right.

The mechanism works by pulling the cable, which squeezes the left and right arms, pressing the brake pads against the rim to apply the brake.

Many of those used on road bikes are double-pivot side-pull type with two axles.

Those found on utility bikes (mamachari) are also caliper brakes, but they are called single-pivot side-pull type with one axle.

• V-brakes

The brake cable runs horizontally through the left and right brake arms, and when the brake is applied, the left and right arms squeeze together to apply the brake.

They have stronger braking power than caliper brakes.

Cantilever brakes are mechanically similar to these.

Since each brake would only be briefly described by name and overview, I will omit the others here.

When to replace brake shoes

Rim brakes, despite some mechanical differences, stop the wheels by pinching the rim from both sides with brake shoes.

Therefore, they are wear-and-tear parts that will inevitably wear down.

So, when is the right time to replace them?

Brake shoes have grooves cut into them.

When these grooves disappear, the brakes will not work effectively, so you should check visually and replace them when the groove depth becomes less than 1mm.

There is also a method of considering replacement based on distance, but it is not highly recommended.

This is because you would need to constantly use a cycle computer to accumulate mileage, and the wear rate of the shoes varies greatly depending on how you ride.

It's easy to understand if you consider that riding on roads with few signals during a long ride versus feathering the brakes when descending a mountain pass will result in a significant difference in wear rate for the same distance.

Therefore, there is also the option of replacing only the front or only the rear.

However, if you replace one, make sure to replace both sides as a set, not just the right or left.

By the way, whether it's a helpful reference or not, for cars, brake shoes are about 5mm thick and are said to need replacement every 50,000 to 100,000 km.

For bicycles, it's a good idea to reduce the distance by one digit, using 5,000 to 10,000 km as a guideline.

Prepare new brake shoes

Brake shoes are sold cheaply and in many varieties on Amazon and other sites.

The surest way is to check the manufacturer and model number of your current brake parts and order the same ones.

You can assume that there is almost no compatibility if the manufacturers are different.

Do not attempt to use them just because of the price.

Carbon wheels have carbon rims, so they require special brake shoes.

If you buy brake shoes for aluminum rims because they are cheaper, you will damage your wheels.

Basically, when replacing brake shoes, you replace the entire unit, including the rubber part and the base connected to the fixing part. However, in the case of high-end cartridge types, it is sufficient to replace only the brake shoe itself.

How to replace brake shoes and precautions

We will explain how to replace brake shoes using caliper brakes as an example.

• Raise the caliper brake lever

Raising the lever widens the gap in the brake arm, making the replacement process easier.

Then, loosen and remove the hex bolt securing the brake shoe with a hex wrench.

• First, temporarily fasten them

New brake shoes have a left and right distinction.

There may also be an arrow engraved indicating the direction of tire rotation.

Be careful not to make a mistake.

Instead of tightening the brake shoes all the way, temporarily fasten them to about 80% of their final tightness.

The holes in the brake arms are elongated, allowing for vertical adjustment.

If they are too high, they will interfere with the tire, causing the tire to wear out prematurely.

On the other hand, if they are too low, the contact area will be smaller, and the braking power will be reduced.

Some people prefer the brake shoe to be perfectly flush with the upper edge of the rim, while others prefer a gap of about 1mm.

As long as there is no interference with the tire, it doesn't matter either way, but since the screw will move slightly clockwise when tightened, there will be no problem as long as there is no interference with the tire after final tightening.

• Also adjust the cable

When brake shoes are replaced, the feel of the lever may change depending on their wear.

Brake cables often have adjustment screws, so turn them to make adjustments.

If the brake reaches its maximum position before you fully grip the lever, your hand will get tired because the maximum load is applied before you can exert full force.

It's better to adjust it so that it reaches its maximum when your fingers are fully gripped.

Cables also stretch over time, so it's ideal to finely adjust braking effectiveness during maintenance.

• Always check at the end

After replacing the brake shoes, always take it for a test ride to check.

It is very dangerous to ride at full speed with ineffective brakes.

Confirm that the brakes work properly, that there are no abnormal noises, and that no screws are loose. Once thoroughly checked, you're done.

External writer: Koichi Okuno