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 improvised 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.
Adjusting the bike’s hydraulic brakes and replacing the pads
The principle of operation of hydraulic brakes on a bicycle is to transfer pressure through the hydraulic line from the brake master cylinder to the brake cylinder in the caliper, which in turn moves the pads. The brake fluid is not compressed, therefore such a system is more reliable and efficient than a mechanical one.
On the other hand, hydraulic lines and the entire braking system require careful attention and constant maintenance, and therefore repairing and adjusting hydraulic brakes often seems to be a difficult task.
Before adjusting: preparing for tuning
The decision to adjust disc brakes on a mountain or road bike will only be successful if the brake system is diagnosed. By the way, the diagnostic measures for hydraulics and mechanics will be different. How hydraulic brakes on a bicycle differ from mechanical ones. we already had a conversation.
In short, in the hydraulic circuit, both pads push the fluid, acting on the caliper pistons, which results in clear modulation and easy handle travel. And in mechanics, only one friction lining is movable. It is brought to the disc by pulling the cable with the brake lever.
However, whatever the brake drive is, it is worth checking:
- Rotor for deformation. For 100% confidence in the flatness of the disc, it is better to unscrew it and put it on a flat surface. A rough estimate can be made while on the bike by rotating the wheel and estimating the distance to both pads through the slot in the caliper. Friction linings must be equidistant from the disc in any position.
- Brake pad wear and integrity. Remove the pads by removing the cotter pin and assess the residual thickness of the friction material. The surface in contact with the disc must be free of pits and dents.
- Cleanliness of pads and rotor. The presence of oil traces and accumulations of dirt on their working surfaces is not allowed. To clean them, you can use fine sandpaper (for example, “zero”) and rags soaked in any cleaner (acetone, ammonia).
- Wheel hub location in frame / fork dropouts. The bushing should fit freely into the seat and abut against the mating surface of the frame or fork. Distortions in the installation cannot be avoided, but they should be minimal, practically invisible. Micron skewing is immediately audible on the brakes in the form of rotor shuffling. This is why disc brakes need to be re-tuned after re-mounting the wheel.
It will not be superfluous to take a look at the state of the drive. With cable disc brakes, check the cable integrity. The end should not be unwoven, and the service life should not exceed 3 years. When replacing the cable, change the shirts. It is not necessary to lubricate it, but if you decide, then do it only with the help of a special lubricant that does not attract dust.
Nothing should leak on the hydraulics. Weaknesses are connections:
- Master cylinder. hydraulic line.
- Brake Lever. Master Cylinder.
- Brake caliper.M
These joints received the status of weak due to the use of cuffs, which dry out and leak over time.
Working with the caliper
Adjusting mechanical disc brakes on a mountain bike is a two-step process: adjusting the caliper and adjusting the brake lever. To adjust the caliper means to align the pads symmetrically with respect to the disc, while the gaps should be minimal.
When adjusting the caliper, it is important to follow the sequence of actions:
- Center the clipper. Loosen the bolts securing the caliper to the adapter and, moving the caliper, find such a position in which the pads will be equidistant from the disc and completely parallel to it. After centering the machine, pull it to the adapter, observing the rule of uniform tightening: turn one bolt ¼ turn, then the other also ¼, and repeat the described procedure again with the first and second fasteners.
- Align the gap between the fixed pad and the disc. Any grade of mechanical disc brake caliper has a bolt or adjusting wheel to move the fixed pad closer / away from the disc. Here the task is to use this adjustment in order to bring the block as close to the rotor as possible, while maintaining the clearance. The easiest way to do this is to move the friction pad close to the disc, but so that it does not bend it, and loosen the bolt a little to get a small gap.
- Adjust the clearance between the rolling block and the rotor. On serious kits, a special adjustment is provided for this. a bolt that moves the block regardless of the tension of the cable. On cheap bikes, this setting is combined with the cable tension. The task is to set the same gap as between the fixed friction lining and the disc.
Advice. Adjust the clearance so that the friction linings grip the disc tightly in the middle of the brake lever travel. To do this, you will need to adjust the tension of the cable using a wing and the position of the fixed shoe (in order to maintain symmetry about the rotor).
For your information. Caliper centering can be skipped if this operation has been performed before and the wheel has not been removed.
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.
Another nail in the list of disadvantages of mechanical disc brakes is that they need to be adjusted more often. This is because one of the pads is motionless. As it is erased, the distance between it and the disc automatically increases. Meanwhile, fluctuations in the values of this gap should be insignificant, otherwise the friction linings will wear unevenly, the quality of deceleration suffers.
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 one nuance should be taken into account. if the hydraulic system is closed, then you will have to adjust the pads manually. 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, when driving for a test, you need to be extremely careful and careful, if necessary, the disc brake system is adjusted again taking into account previous errors.
How to Adjust Disc Brakes on a Bicycle: Techniques for Hydraulics and Mechanics
Normally, the disc brake stops the wheel as quickly as possible, allowing the force to be dosed on the verge of blocking the rotor. Deviations appear after replacing the cable, pads and overhaul. However, the settings are violated during long-term use, as well as after removing the wheel, for example, to seal the bicycle camera at home. How to avoid the famous shuffling of the rotor, how to eliminate the braking, and, in the end, how to restore the factory braking character. these and other questions are answered by the editorial staff of Autobann magazine.
Checking and adjusting: where to start?
Answering this question, it should be noted, first of all, that not all parts need adjustment. If the brakes react quickly and are triggered immediately after the handle is clamped, abruptly and without delay, then most likely such parts do not need repairs, and it will not be difficult to set them up correctly on the bike with your own hands. This process will take several minutes and does not require any special approach or skills.
The situation is much more complicated with those systems in which there were some failures. Examples include increased chain-to-core disc brake clearance, loose bolts, sticky handles, or a defective rotor. Most often, the problem is that the lever responsible for tightening the cable is working slowly due to the fact that the brakes are not adjusted correctly. This type of breakdown is the most common and easiest to repair.
Often, in order to adjust the brakes with such a breakdown, it is enough just to tighten the cables and thus “make” them work correctly. Sometimes it is necessary to tighten the bolts, lubricate the rotor or brake pads. In some cases, this is not enough and it is necessary to completely replace one or several components of the system at once.
Simply put, sometimes it’s enough to just spin the wheels one at a time and make sure that the braking systems are working properly. But it also happens that the cables or the rotor need to be tuned. Such problems should not be treated negligently, because both the comfort and safety of the cyclist depend on how correctly all the parts of the bike work.
DIY bike brake repair
How to tighten the rim brake on a bicycle?
No matter how cool your bike is, it’s almost impossible to completely avoid the problems associated with it. This should be understood and taken into account, because the flawless operation of the rotor and the entire system of rim brakes, wheel rotation and switches largely depends on how carefully the bicycle owner treats his vehicle. The pads and cables connecting all their components must be in proper condition, otherwise, a major overhaul of the entire system is simply inevitable.
It is impossible to avoid all problems. However, you can protect yourself from most of them. To do this, you need to know what the operation of the entire system is, what the rotor, caliper, each lever and all available handles are. You should also understand what all the bolts on the bike are responsible for, and understand what, in general, the brakes are.
Some work properly and do not need adjustment at all. However, such luck is rare, and often you have to answer the question of how to adjust the brakes on a bicycle, in an accelerated manner. Not everyone is accustomed to monitoring the condition of both rim brakes and disc brakes, therefore, most often, problems “appear” suddenly, and require immediate attention.
Final brake adjustment on our BMX bike build
In order to avoid such unforeseen problems, and postpone the repair of your wheels and disks, it is better to check them again and make sure that everything is in order. If this was not done in a timely manner, it is important to remember what adjustment of the brakes on a bicycle is and how to do it correctly.
How to set up the brakes?
In order to set them up correctly and avoid common mistakes, it is important to understand what they are and how they differ. Repairing disc brakes is somewhat different from working on adjusting rim brakes, and you should not forget about it.
Determining the type of brakes is not the only part of setting them up. It includes a number of steps to help get even the most frustrated brake pads back to normal. Below you can see the sequence of the setup process:
- The first step is to check the correct type of brakes. As already mentioned above, it also depends on what actions will need to be taken next;
- The next step is scrolling the wheels and sequentially squeezing the right and left handles. This will help detect the problem of both disc and rim brakes, if any at all;
- Next, you need to check the condition of each cable, and find out how quickly they react to braking signals;
- The bolts located on each of the handles will help you tighten the cable so that it responds in a timely manner to the signals given;
- In cases where it is not possible to adjust the cable with your hands, you can use the caliper. With its help, you can easily pull up the desired cable, and adjust it to the desired state. The bolt at the end of the cable, as a rule, is tightened to the stop;
- The next thing to check is the brake pads. Repairing this part of the system is difficult, so you should not start it. As a rule, regular lubrication of the pads helps to increase their life, and greatly simplifies the adjustment and repair of the entire rim or disc brake system;
- When there is not enough lubricant to keep the pads running, it is worth checking the condition of the bicycle wheels. Adjusting them may help to avoid costly disc brake replacement. If we are talking about setting up rim brakes, this problem does not arise. the pads in them can be easily replaced with new ones or tightened.
Overall, these tips should be enough to get you started with what brakes are and how they work. However, rim and disc brakes have their own fundamental differences, which would be unreasonable to ignore.
The first thing to note is that rim systems are much more common than disc systems. The latter have recently entered the market, and therefore are not yet in such wide demand among buyers.
There are significantly fewer problems with disc systems than with rim systems. with the right attitude to the bike and careful use of each handle, lever and wheels, there will be no problems at all. With proper attitude to your bike, it will not need repairs, and a simple setup will not cause any difficulties.
how to adjust disc brakes on a bicycle
HOW TO SET UP DISC BRAKES ON A BIKE: INSTRUCTIONS
Setting up disc brakes on a bicycle is not a complicated process. Now see for yourself. Let’s find out how to set up disc brakes on a bicycle yourself without asking for professional help:
- After fixing the wheel, the caliper should be centered in relation to the rotor by picking up and installing between the mounts on the frame and the caliper washers of various thicknesses that are included.
- The position of the caliper will vary depending on how tight the bolts are. Accordingly, the thickness and number of washers will need to be selected to a fraction of a millimeter.
- In the case when the rotor is in contact with both pads and friction occurs, the pads must be diluted. To do this, slightly unscrew the special hexagon on the caliper, while the brakes will start to work later.
- If you want to achieve a shorter brake lever travel, the hex must be screwed in. This may be due to an uneven brake disc that will need to be leveled.
- During the robot, do not turn the bike over to avoid air entering the system. Also, do not press the handle if there is no oil in the system, and the rotor does not stand between the brake pads, otherwise they will shrink, after which you will have to remove the caliper and open the brake pads with a screwdriver.
- When all operations are completed, tighten all the bolts again. When checking the robot, we carefully monitor that the brake disc does not warp or shift when pressing the brake lever.
How to Adjust V-Brakes
Replacing rim brakes
The first thing to start with is removing the nuts and washers. After that, the old pads are separated from the main braking device. New pads are put in place of the old ones. In this case, they need to be directed to the rim. To avoid squeaks while riding, make sure that the pads are in full contact with the rim.
Adjusting mechanical disc brakes on a bicycle.
Disc brakes are becoming popular today, and the craze for them began about 4 years ago. The point is not at all about reliability, but about the fact that their presence on the bike gives the impression of a racing motorcycle or emphasizes the coolness of the owner of such a bike.
Renewal and replacement of pads
The most common service is replacing or renewing a bicycle brake pad.
Updates are usually sufficient after long-term storage. The surface of the rim and pads is degreased, and, depending on the remaining thickness of the rubber, its top layer is removed, as it “dunks” from frost during storage, as well as from heating during active braking.
Replacement cartridges for cartridge brake pads
Pads are replaced less often. After unscrewing the screw, the old shoe is pryed off and removed, and a new one is installed in its place. Here, accuracy is required when choosing, since there is no single standard, and the groove for the screw may not fit, and the shoe itself on the site may not lie. Fortunately, any sizing problem is dealt with with a sharp knife. In the case of cartridge pads, undercutting will most likely not help, but such cases are quite rare.
If the adjustment of the screw is not sufficient, you will need to shorten or lengthen the cable. This is done on the brakes themselves. Opposite the shirt, on the opposite element, the cable is clamped with a lock, which is unscrewed with a hexagon. To do this, unscrew the retainer bolt, tighten or loosen the cable, screw the retainer back. The excess length of the cable can be cut, although many leave it twisted in case of breaks, although practice shows that such “reserves” do not help anyone.
After loosening or completely unscrewing the pad fixing screws, they can be moved in any direction.
Unscrewed pads fixing screw
This adjustment should be done without removing the wheels in order to clearly position the shoe. So, how should the block stand:
- The shoe should be at the level of the rim, not going beyond it by a millimeter.
- When checking for clearance from either side, the block must be in both the braking position and in the open position parallel to the rim.
- When scrolling the wheel, the block must be pressed exactly along the rotation vector. deviation from it will damage the brakes.
After installing the pads in accordance with these conditions, the screws are tightened, the brakes are checked.
A bicycle disc brake is a combination of a steel disc (rotor) located on a hub with a caliper. a device that actually clamps the disc with the brake pads. From the brake lever on the handlebar, the force is transmitted to the brake by a cable (mechanical disc brake type) or through a hydraulic mowing line (hydraulic disc brakes).
Bicycle disc brakes also have their advantages. They are:
- less clogging when driving;
- can work without problems while driving on snow or mud;
- as smoothly as possible (in contrast to rims) adjust the braking force;
- do not react to slightly curved wheel geometry (small “eights” are not a hindrance for them);
- do not affect the wear of the rim;
- and do not require expensive maintenance.
Many bicycle disc brakes have only one moveable brake pad. The second is fixed statically relative to the frame structure. This greatly simplifies and reduces the cost of the caliper. But, however, as the wear and tear, the cyclist will have to tighten the brake pad, which is stationary.
Brake discs are standard sizes. These are 140, 160, 180, 185, 203 or 220 millimeters.
Setting v brake rim brakes
Today, mountain bikes are widely used with v-brakes, so here’s an example of how to adjust the brakes of a bicycle in the case of a rim brake. Setting up other rim brakes is done in the same way. The only difference will be that the bolts and screws that need to be twisted may be in other places. And the approach is the same (even in the case of disc brakes).
So, the basic rule is that the pads should be parallel to the rim. The clearance between the shoe and the rim should be 1 mm. And both pads must be symmetrical.
Scheme of work
The principle of operation of the system is based on the use of the friction force arising in the process of interaction of brake pads and wheel rim.
Structurally, any rim system includes:
- paired levers for the front and rear wheels;
- brake pads made of dense rubber;
- control handles;
- cables connecting all components;
- brake cable covers.
The scheme of the kit is quite simple. When physically acting on the control handle, the force is transmitted through the cables to the levers with pads fixed on them. There is a clamping of the wheel rim between the surfaces of the shoes. As a result, the bike slows down or stops. The more the application force, the more the rim is clamped, the faster the object slows down.
Compared to other types of rim braking mechanisms, they have a lot of advantages: they are not expensive, easy to maintain and repair, have a high degree of modulation, and practically do not have a harmful effect on the hubs and spokes of the wheel.
At the same time, this design has a number of significant disadvantages, which are recommended to be taken into account when choosing and purchasing a bike.