How to adjust disc brakes on a shimano bike

Disc brakes

Disc brakes provide excellent braking modulation and great power in all weather conditions. They also allow for larger tires than rim brakes and don’t care if your wheel is bent a little. However, quiet, predictable friction-free operation depends on fractions of a millimeter of clearance between the pad and the rotor.If the brakes start to rub, there may be several reasons, so we added a menu that will help you check all possible problems, as well as adjust the calipers themselves.

How to adjust disc brakes on a bicycle

adjust, disc, brakes, shimano, bike

The advent of disc brakes on road bikes revolutionized handling and confidence in all weather conditions, but they require proper alignment to perform flawlessly.

Manually center the caliper

To manually align the pads, make sure the disc is in line and centered between the pads.

Manual brake alignment is just a case of partial movement of the caliper to the side until there is a consistently clean clearance between the pad and rotor as the wheel rotates.

Again, tightening the bolts, which requires you to press hard enough to move them, will make fine adjustments easier. The use of a light background is also of great help in determining the balanced position of the brake. Don’t be surprised if you have to make a few small changes in position and pull-ups to keep the rotor running clean too.

When viewed from above, ensure that the caliper is perpendicular to the rotor by looking at the brake from the front or rear. This shouldn’t be a problem with flat mount brakes as long as the frame and fork are properly aligned. However, some strut-supported brakes use a pair of concave and convex washers that can move slightly to the side. Again, this is just a case of small adjustments to keep the rotor running cleanly through the brake.

Inspect the caliper

Check that the brake pistons move freely by looking through the caliper

First make sure the axles are tight and the wheels do not wobble in the frame / fork. Now pull the brake while looking at the pads on either side of the rotor. They both have to move the same amount at the same time. If only one pad moves, you need to pull the wheel out and slide the pistons back into the caliper using a flathead screwdriver, tire lever, or special piston tool.

Check the correct rotor

The disc can be straightened by bending it very carefully with a rotor straightening tool or a clean wrench.

If the brake is working properly, check the straightness of the rotor by checking it for rolling between the pads. If you need to straighten it, use a rotor straightening tool if you have one, or a clean adjustable wrench if you don’t have one. Bend the rotor only very carefully and gradually so as not to bend it in the wrong direction. If you can’t see the rotor between the pads, place your bike against a light background. Even a piece of white paper on the floor will do. Make sure the rotor is firmly attached to the hub as this can cause friction as the rotor moves slightly.

Required tools

Tools you need to adjust your bike’s disc brakes

You will need a 5mm Allen key or T25 Torx wrench depending on your brake mounting bolts.

A wide screwdriver, wide wheel lever or similar flat lever can be used to reset the brake cylinders.

To straighten a bent rotor, you will need a slotted rotor straightening tool or a large clean adjustable wrench.

Center the caliper

Loosening the caliper fixing bolts allows the caliper to be adjusted

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In most cases, the problem occurs due to a slight change in the brakes or a change from the wheels to wheels with a slightly different disc position. To re-align the brakes, you need to loosen the mounting bolts a little so that you can simply slide the caliper to the side. The strut brakes are bolted through the caliper. Flat mount brakes are bolted to the bottom of the frame and sometimes to the far side of the forks.

Sometimes you can re-center the brake by pulling on the lever to clamp the caliper onto the rotor. Then you tighten each bolt gently in turn, and in theory your brake will be perfectly centered and ready to ride. Unfortunately, this doesn’t work as well as most guides say, so be prepared to build everything by hand.

Adjustment of mechanical disc brakes

Mechanical disc brakes, as well as shoe brakes, consist of a handle, a “shirt”, a drive cable, but instead of pads they have a brake disc (rotor) and a machine called a caliper. In order to set up disc brakes, you must:

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  • set all adjustments to zero;
  • unscrew the cable fasteners, and then choose its optimal slack;
  • loosen the bolts holding the caliper, since adjustment is possible only in the unfolded position of the caliper;
  • set the machine in such a way that the gap between the brake pads and the rotor is the same;
  • tighten the bolts and firmly fix the machine.

Adjusting hydraulic disc brakes

In most cases, the hydraulic brake has an automatic brake pad function. But there are situations when it is necessary to manually adjust the brakes.

  • release the two fixing bolts that hold the caliper;
  • press the caliper tightly to the fork and squeeze the brake lever on the handlebar until it stops;
  • holding it, fix the bolts on the caliper in the closed position.

This will allow the pads to wrap the brake disc evenly on both sides and adjust the brake module.

If, however, some elements of the system were serviced or replaced with new ones, then for adjustment it is necessary to press the control knob about 20 times. This will make it possible to set the pads relative to the rotor in the working position.

When setting up, certain problems may arise, most often it is the sagging of the brake lever. It is possible to normalize its position by pumping the system (in the event that there are air bubbles), but if the problem is in brake fluid leaks, then it is necessary to replace the hydraulic line.

How to adjust the brakes on a bike

Adjusting the brakes of the V-brake

Before adjusting the brake, disconnect the applied jacket on the front and rear brakes. This can be done by simultaneously pulling the metal guide on the cable, while simultaneously pulling the brake lever to the wheel rim. Next, you need to perform the following steps in the exact sequence:

  • to determine the balance and symmetry of the pads on the rim, it is necessary to loosen the screw with which they are attached to the lever and set them, gradually pulling them to the rim;
  • it is necessary to set the working plane of the pad in such a way that its front part touches the rim before the rear one. To do this, put a thin object under the rear part, press the block to the rim and fix the nut completely;
  • center the levers. This is important because the levers on the pads must be centered in order for the pads to come into contact with the rim at the same time;
  • set the pads in the unfolded position relative to the wheel rim. This stage is carried out in order to establish the sharpness and smoothness of the brake pads, by optimally adjusting the cable tension.

Determining the type of adjustable brakes

Regardless of the braking unit to be set, always start with the control knob. There are adjusting screws in its body. The purpose of this stage of setup is to select the most suitable resistance force when pressing, as well as a convenient position of the handle in relation to the steering wheel.

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Three types of braking systems are installed on sports and mountain bikes:

  • rim brake V-brake;
  • disk mechanical;
  • disc hydraulic

A common feature when adjusting these types of braking modules is a thorough check of the leading line (cable or hydraulic line). For example, in the case of a hydraulic brake, this is an inspection of the hydraulic line for possible defects, in the presence of which a corresponding replacement of the line takes place and the subsequent bleeding of the entire system. In the case of brakes, where the control line is a cable. It is necessary to inspect it for possible places of rupture and abrasion, and also to inspect the brake “jacket”. In case of visible defects, replace this or that element.

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Of course, adjusting bicycle brakes may not always work out the first time. A little practice and this process will cease to be a problem for you. over, it is not at all necessary to be a specialist in adjusting all types of brake systems. It will be enough for you to understand the process of adjusting the system that you use and which is on your bike. There are big advantages to being able to fix a breakdown or adjust the brakes on your own.

Even in spite of frequent and careful adjustments of the brake systems, remember that it is better to replace worn parts immediately. After all, the adjustment and serviceability of the brakes is the guarantee of your health and safety.

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.

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.

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.

How to check and adjust the brakes

There are clear instructions for checking and adjusting the brake system of a bicycle. If you stick to it, then the whole process will take little time and will be effective.

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Procedure for checking and adjusting the brake system of a bicycle:

  • Dry brake test. It is necessary to raise the front wheel and, having unwound it, press the left brake lever. If the wheel comes to a sudden stop during this test, the braking system is in order and no maintenance is required. Honor has one caveat. if the brake lever touches the steering wheel, then you just need to pull the cable. The operability of the rear wheel brake system is checked in the same manner. To tighten the cable, you need to use curly bolts. just tighten them a little and, if only minor adjustments are required, this will correct the situation. It often happens that such a minimum adjustment does not work. in this case, we look where the end of the cable is on the bike (it is always longer than necessary in advance), unscrew the bolt that holds it. It remains only to tighten part of the cable with pliers and tighten the bolt, applying the possible force.
  • Checking the brake pads. After the brake levers have been tested, the condition of the brake pads should be carefully examined. However, the order of action can be changed. first work with the pads, and then with the handles.

The setting of the brake system for rim and disc type is different, since different rotating mechanisms and pads are used.

Adjusting the brakes on a bicycle

Adjusting the brakes on a bicycle should be carried out regularly. such maintenance will guarantee the safe operation of the vehicle. There are two main types of brakes on modern bicycles. rim and disc brakes, but disc brakes can be mechanical or hydraulic. The process of their maintenance will depend on what type of brake system is installed on a particular bike.

Setting up disc brakes

As a rule, adjustment of disc brakes consists in periodically tightening the cable. But often you have to replace the pads, however, on disc brakes they wear out longer than on rim brakes. First you need to find out which specific disc brakes are installed on the bike. brake pad adjustments for hydraulic and mechanical systems will differ.

Experts recommend taking note of the following points:

  • If there are hydraulic disc brakes on the bike, then replacing the pads may not be necessary. they are able to do it on their own. But there is one caveat to Honor. if the hydraulic system is closed, then you will have to adjust the pads in manual mode. for this, special valves are provided.
  • If you have to adjust disc mechanical brakes, you will need to pull the cable according to the above instructions and check the location of the pads. the distance between them and the disc should be within 0.2-0.4 mm.
  • In order to adjust the pads with disc mechanical brakes, you need to use special bolts. by tightening them, you can see how the pad moves. You need to be especially careful when setting the distance between the pad and the disc. 0.3 mm is too small, it is easy to make a mistake.

After carrying out the work, be sure to check the operation of the brake system in action. ride your bike for a few meters and try to brake. If the cable was overtightened, or the pads are too close to the disc, then too sharp braking will occur. this is a “surprise” in which the cyclist begins to move forward, but without his vehicle. Therefore, during a test drive, you need to be extremely careful and careful, if necessary, the disc brake system is adjusted again taking into account previous errors.