How to tighten disc brakes on a shimano bike

Setting up mechanical disc brakes on a bicycle

In cases where one of the elements of the brake system fails, which makes it necessary to replace it, adjustments should be made. There are several sequential steps that will help you cope with this task efficiently and quickly:

Adjusting Shimano Mechanical Disc Brakes on your Bike Friday

  • We check all fixing elements (bolts). If one or more of them are not tightly screwed in, then they lose their functional purpose.
  • We unscrew (not completely, but only in order to loosen the fixation) the lock nut, after which we tighten the cable tension adjuster on the steering wheel. We bring the locknut to the previous position (fix). With the adjustment located on the caliper, we perform the same actions. Pull the cable by hand after loosening the lock. When the required tension is reached, screw the retainer back.
  • Dismantle the car.
  • As you know, one of the pads is motionless, and the other is vice versa. It is important to achieve an equal distance from the center of the caliper slot for proper rotor positioning. The fixed block is adjusted with a lock nut. By loosening it, you can move the position of the element as much as necessary. The movable block is adjusted by rotating the cable tension adjustment on the caliper. Having reached the desired position, we fix the non-static block.
  • We adjust the caliper. It must be aligned exactly in relation to the rotor.

That’s all you are done. It often happens that the rotor still rubs against the block when moving. This is not surprising, because it is not always possible to align the pads themselves exactly. Determine which one is not fixed correctly (just push the bike and see, this will be enough) and adjust the desired one as described in the instructions above. But sometimes the cause of friction is rotor deformation. To do this, it must be aligned. If the flaws are too serious, it is better to replace.

Device and principle of operation

The difference between the principles of operation of disc and mechanical brakes is insignificant. But, there are still differences in their device. Let’s consider step by step, starting with the mechanical type, which is arranged as follows:

  • Brake handle. It is fixed on the steering wheel, for ease of squeezing, with a clamp. It is designed to transfer force to the brake pads, bringing them into action.
  • Cable adjuster with lock nut. The first element serves as a regulating device for limiting the cable tension. The second is for fixing the regulator itself.
  • Brake lever adjuster designed to determine a comfortable distance to the handlebars.
  • Cable jacket. protecting it from dirt, mechanical damage.
  • To fix the cable, a clamp in the form of a bolt is used, with the possibility of adjustment
  • The mechanism that allows the cable to be set in motion, when pressed on it, is called a caliper. Its action is not possible without brake pads. rubber or metal fragments that ensure a tight clamping of the disc.
  • Directly disc (rotor). It locks onto the wheel hub.

Figures 1 and 2 show schematically all of the above details.

tighten, disc, brakes, shimano, bike

Figure: Bicycle brakes

Figure: appearance of the brake lever with main elements

Diagnostics of the brake system

As with the human body, which functions as a whole, before fixing brake problems on a bicycle, diagnostics should be carried out to determine the extent of brake damage. After all, if the block is worn out, from which the impact on the disc becomes much worse, and there is no stopping effect (due), then only it needs to be replaced, and not the system as a whole. So, below are some of the diagnostic steps you need to take to identify the causes of your bike‘s “ailment”:

  • Deformation of the rotor can be one of the reasons for the malfunctioning of the braking system. Therefore, removing it is a top priority. When you unscrew the clips and remove the rotor, it must be placed on a flat surface, such as a mirror. Carefully inspect how tightly and evenly the rotor adheres to it, and if you notice irregularities, it means that they need to be corrected.
  • We dismantle the brake pads to carry out a visual inspection for damage. This action is as follows: find the extension on the caliper, and then turn the pads until they are removed. It is not difficult to visually determine the wear on their surface. So, the figure shows that the block on the right is already completely worn out and requires immediate replacement.
  • Figure: Determining Pad Wear
  • The next “candidates for close inspection” are cables and shirts. This item is suitable for those modes of transport where mechanics are used. It is necessary to check the cable for fiber breaks, deformations, and so on. As for the shirts, remember that their function is to protect the cable from negative factors (accumulation of dust, moisture). Therefore, cracks or breaks simply should not be present here. Both elements must be lubricated before installation / replacement.
  • For hydraulics, there is also a test exclusively inherent in this type of system. the condition of the hydraulic line for leaks. It is important to understand that in the presence of leaks in the hydraulics, the proper pressure may simply not be exerted on the pads, which automatically disables the system. Damage to the hydraulic lines is quite likely, which are revealed by visual inspection. over, it does not matter at all whether this damage is strong, or insignificant. It is also necessary to check the junction of the brake line, caliper and master cylinder. A rod extends from the brake lever to the piston. another potential place from which fluid can be vented in case of mechanical damage (on the cuffs). After dismantling the brake pads, it is necessary to check for leaks on the caliper itself.
  • The rotator, like the pads themselves, can get dirty while using the bike. Both oil and dust accumulate here, forming solid layers that interfere with the operation of the system. Adjusting the brakes without cleaning the rotor and pads from dirt is a mistake. Cleaning can be done with fine-grained sandpaper. But for this you need to dismantle both parts so that the cleaning is done as efficiently as possible.
  • The final is wheel adjustment. It should not be skewed to the side in any way. You can check this simply by placing the bike on a flat surface and performing a visual inspection. If the wheel is tilted to the side, it must be aligned (loosen the eccentric, then adjust the wheel).
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A set of such activities is required. All this can be done quickly enough if you have all the necessary tools (screwdriver, wrenches). Next, we go directly to the processes of adjusting and installing the brakes.

The main differences between hydraulic and mechanical disc brakes

The main difference between the hydraulic and mechanical types is the principle of transferring the force exerted on the handle to activate them. So, if a cable serves as a conductor of the pressure force in mechanics, then in hydraulics it is a liquid. Both brake and mineral oil (depending on the manufacturer) can be used as a fluid. Both of them are good in their own way, and their effect differs from each other to an insignificant degree. The photo shows a schematic representation of the device of the hydraulic type of disc brakes.

Photo: the main elements of the hydraulic system of disc brakes

Adjusting the rim brakes

Mountain bikes use a v-brake braking system. by its example, we will consider the principles of tuning, as it is also available on other bicycles with rim brakes. The difference can only consist in a different arrangement of bolts and screws that will need to be tightened / tightened.

How To Adjust Mechanical Disc Brakes On A Bike

Note: it is important to observe three main rules:

  • the pads should be parallel to the rim;
  • the gap between the rim and the block should not be more or less than 1 mm;
  • the pads should be symmetrical with respect to each other.
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How to achieve these guidelines when adjusting rim brakes on a bicycle:

  • You need to find a hex nut. it fixes the pads. To loosen it and set the brake pads in the desired position, you need to press the brake lever and watch how the shoe touches the rim. By releasing the brake lever, the shoe can be set to the desired position. it moves up, down and at an angle.
  • The distance between the block and the rim of the wheel should not be more than 1 mm, although in some models of bicycles there are also 2-3 mm. exact information about a specific vehicle can be obtained either from the instructions for it, or on the Internet for technical characteristics. It should be for Honor that the wheel should be braked even with the smallest pressure on the brake lever. That is, if the wheel stops only when the brake lever is fully pressed “all the way”, then this is incorrect.

After carrying out all the specified work, it is imperative to check the operation of the brake system. First, this is done at idle speed. lift the front wheel up, spin it up and press the handle sharply, then do the same with the rear wheel. The next step is to check the operation of the brake system “in action”. get on the bike and ride 3-5 meters, braking sharply. If the bike stops even when the brake lever is pressed slightly, then the system has been serviced correctly.

Advantages and disadvantages of mechanical brakes

Mechanical brakes are cheaper, cables and casings (jackets), in which they are located, are quite reliable, more accessible than hydraulic lines. It is also important that the repair of a mechanical brake in the case of a bent disc is easy to carry out on your own.

How to set up and adjust disc brakes on a bicycle

New bicycles are often equipped with rim brakes, or V-brakes, and Soviet bicycles have always been fitted with the only existing caliper brakes. Currently, this is due to the desire to reduce the cost of the design: it is no secret that many cyclists dream of changing the brakes to disc brakes as soon as possible. Often, even when choosing a bike, the costs for changing the brake system are included in the amount.

Below we will show you how to set up disc brakes on your dream bike.

Since the principle of operation of disc brakes is different, it is impossible to adjust them according to the same scheme. Brake disc mechanisms are:

  • mechanical. In this case, the braking energy is transmitted mechanically, using a cable;
  • hydraulic brakes, which have a specially laid hydraulic line, and the braking energy is transmitted by the pressure of the liquid column.

How to set up disc brakes on a bicycle

Running a bike is one thing, but fixing it is another. Even skilled and experienced cyclists are faced with the problem of incorrect / defective disc brakes. You can deal with this phenomenon if you clearly know the principle of operation and the structure of the system. And you should start with these main points.

Device and principle of operation

The difference between the principles of operation of disc and mechanical brakes is insignificant. But, there are still differences in their device. Let’s consider step by step, starting with the mechanical type, which is arranged as follows:

  • Brake handle. It is fixed on the steering wheel, for the convenience of squeezing, with a clamp. It is designed to transfer force to the brake pads, bringing them into action.
  • Cable adjuster with lock nut. The first element serves as a regulating device for limiting the cable tension. The second is for fixing the regulator itself.
  • Brake lever adjuster designed to determine a comfortable distance to the handlebars.
  • Cable jacket. protecting it from dirt, mechanical damage.
  • To fix the cable, a clamp in the form of a bolt is used, with the possibility of adjustment
  • The mechanism that allows the cable to be set in motion, when pressed on it, is called a caliper. Its action is not possible without brake pads. rubber or metal fragments that ensure a tight clamping of the disc.
  • Directly disc (rotor). It locks onto the wheel hub.
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Figures 1 and 2 show schematically all of the above details.

Figure: Bicycle brakes

Figure: appearance of the brake lever with main elements

How to pull

Proceed in the reverse order of loosening the cable and you will get the desired result.

Adjusting hydraulic disc brakes on a bicycle with your own hands

The hydraulics are called self-adjusting. Where this status came from is unclear. The centering of the pads relative to the disc can also get lost here. And the shuffling of the rotor itself is one of the first complaints from owners of even new bikes.

In general, setting up hydraulic disc brakes on a bicycle is easier than using cable brakes. But drawing a parallel between adjusting the brake mechanism and cleaning the chain, we can say that working with the brakes is still more difficult than washing the chain at home.

The main goal is the same: to center the caliper, check if the pads are equidistant from the disc, adjust the handle stroke, if its design allows it. It is necessary to carry out the adjustment step by step:

  • Loosen the bolts securing the caliper to the adapter.
  • Clamp the brake lever to the stop and fix it in this position using the available means (wire, electrical tape.).
  • Check the position of the rotor. It should be located exactly in the center of the caliper slot. If the disc is bent, then the pads are not equidistant from it. The required position of the friction linings and the rotor can be achieved by bending the disc in the direction opposite to the observed bending. Fluid will flow from one piston to another and the pads will align.
  • Tighten the caliper mounting bolts alternately. Use the 1/4 turn tightening technique found in the Mechanics Set-up Technique.
  • Adjust the position of the handle using the screw on its body.

Particular questions on mechanics

How to set up and adjust disc brakes on a bicycle

New bicycles are often equipped with rim brakes, or V-brakes, and Soviet bicycles have always been fitted with the only existing caliper brakes. Currently, this is due to the desire to reduce the cost of the design: it is no secret that many cyclists dream of changing the brakes to disc brakes as soon as possible. Often, even when choosing a bike, the costs for changing the brake system are included in the amount.

Below we will show you how to set up disc brakes on your dream bike.

Since the principle of operation of disc brakes is different, it is impossible to adjust them according to the same scheme. Brake disc mechanisms are:

  • mechanical. In this case, the braking energy is transmitted mechanically, using a cable;
  • hydraulic brakes, which have a specially laid hydraulic line, and the braking energy is transmitted by the pressure of the liquid column.

How to adjust disc mechanical brakes on a mountain bike

Mechanics are gradually becoming history. Now it can still be seen in the budget line of Russian Stels, Forward and Stern. Considering the price, there is no need to talk about the belonging of brake system parts to such global brands as Shimano and Sram. Usually this is some kind of noname kit that has a minimum of settings.