Brakes for a bicycle, like for any other vehicle, are an indispensable element necessary to control the bicycle and ensure safety. The following types are distinguished:
Drum brakes. 2. Rim brakes. 3. Disc brakes.
Which type of brakes should you choose? To answer this question, it is worth understanding the features of each type of brakes.
This is the most popular type of brake today. Their principle of operation is as follows: when a force is applied, which is transmitted through a cable to the brake levers, the brake pads on the brake levers fit tightly to the wheel rim, which ensures braking. Rim brakes are available in cantilever, caliper and V-brakes.
Mechanical disc brakes
Mechanical disc brakes, as a rule, are installed on mountain bikes (Forward Next 27.5 2.0 disc (2020), Forward Iris 26 2.0 disc (2020), etc.) and touring bicycles (Forward Yukon 2.0 disc), less often on city bikes (to For example, Forward Tracer 26 2.0 disc (2020)).
Disc brakes device
A disc brake consists of a brake disc (rotor) attached to the wheel hub, and a brake machine (caliper), inside which the brake pads are located. Disc rotors come in several sizes: 140, 160, 180, 185, 203 and 220 mm. The larger the rotor diameter, the more efficiently the brake works, as the arm of the brake force lever increases.
The caliper (brake machine) is mounted on the fork or on the frame. Inside the caliper there are two brake pads that are pressed against the rotor by one or more pistons.
Brake pads can be filled with metal filings or organic material. Metal-filled pads last for a long time and are more resistant to wear. Organic pads are softer, wear in quickly and provide smoother braking.
Most often used on road bikes, but there they are gradually being replaced by other types of brakes. The name of the brakes speaks volumes about its design: the brake pads are pressed against the rim by curved levers that look like pliers. Caliper brakes installed on Forward Impulse bikes (2020).
Advantages and disadvantages of hydraulic brakes, their application
The main advantage, in fact, which prompts the owners of hydraulics to use it, is the accuracy of the braking performance, its clarity and responsiveness. With prolonged use of mechanical brakes, either the brake pads are worn out, or the cables wear out (sometimes break). Using hydraulic brakes will not present you with this problem. The main thing here is not to allow kinks of the tube in which the brake fluid is located, well, with a damaged tube, you can, accordingly, be left without brakes altogether. The rest of the hydraulics is at a high level and there must be a future behind it.
Since the use of hydraulics makes the brakes feel better and makes them act more clearly, they are very often used on powerful bicycles. For example, on bicycles designed for freeride or trial. For bicycles that are used in extreme conditions, where the speed of the bicycle’s reaction to braking is one of the main selection criteria.
The disadvantages include the complexity of the repair. For example, in the field, a punctured hydraulic line can become a significant problem for you, which will be quite difficult to eliminate. If this happens during the race for the winner, there is a big chance that you will be the last one. Some more disadvantages lie in the fact that there are difficulties in installing the trunk, since the brake line can become a hindrance in this. Difficulties in removing and putting on wheels on forks. you need to be very careful so as not to accidentally damage the brake pipe.
Bleeding hydraulic brakes
When bleeding the disc brake system, keep the discs and pads away. First of all, unscrew the master cylinder and fasten it again so that the top of the cylinder is horizontal. Since we will inject liquid into the system, it is better to work with a flat surface. Now you need to remove the top cover from the master cylinder. Most likely it is secured with Phillips screwdriver screws. Make sure the head of the screwdriver is sharp. Some screwdrivers are thorium-coated. As with everything, it is important to use the right tool in your work. like with a girl.
By unscrewing the cover of the master cylinder, you can see the membrane of the master cylinder. It expands and contracts as the temperature of the brake fluid changes. Under it you can see the brake fluid. It must be emphasized that you must use fluid for your disc brake system. If the fluid is not the right one, you run the risk of serious injury due to inoperative brakes. But most importantly, you can damage the entire brake system, and its repair is very expensive.
Tools that will be needed for pumping.
Each disc brake system can be pumped differently. Read the manufacturer’s instructions. You can use your own methods, but be extra careful and be sure to check the brakes before riding. Here we will be looking at pumping the shimano system. A special tool is used for it, which is attached to the main cylinder body. Liquid is collected in its bottle; it can be hung on the handle. It looks like a bottle with a tube extending from its cap, which adapts to the brake system. When we pump the liquid from the pad through the system with a syringe, it will pass through the master cylinder into the tube. There is a small hole on the bend of the tube with a tube and the liquid will flow into the bottle.
Now you need to draw the liquid into the syringe. It uses a bottle of Shimano mineral-based disc brake fluid. I emphasize once again that you need to use the correct fluid. Draw liquid into a syringe. To bleed the brake system, you need to dial as much as possible. If you get air bubbles in the syringe, flush them back into the bottle so that no air remains in the syringe, otherwise you will not reach your goal. You bleed the system in order to get rid of the air in it and fill it 100% with brake fluid.
Now you need to inject the liquid through the machine. When you inject fluid through a typewriter, it can immediately open the piston valve and there is a possibility that the valve will pop out of the body, so many disc brake manufacturers include a gasket with them, which can be placed where the pads are usually located when pumping. If the gasket does not fit your brakes, you can use a spare brake lever and something else that will prevent the valves from coming out of the machine body.
Bring fluid to the very end of the hose and slide the hose onto the inlet nipple. Open the inlet nipple with a wrench. You can now supply fluid to the system. Gradually. When pumping fluid through the system, it is important that it does not leak. Some brake fluid compounds can damage paint. The mineral composition is harmless. And with other compositions, I advise you to cover the frame with something to protect the paint from damage. When pumping fluid into the system, tap on the pipes with an assembly wrench or other tool so that air that could remain in the main cylinder housing is released. Stop dispensing beforehand. Now close the inlet nipple and you can pick up the tube. Check again that the valves are all recessed into the machine body. The fluid that you pump through the system can now be removed. The fluid should reach the top edge of the master cylinder housing. There should be no air here. Clean the master cylinder diaphragm, if necessary, so that there is no contamination. Put it on top and close the lid.
Disc cleaning fluid can be used to wash off remaining brake fluid from the steering system, clean discs and pads, if required. Clean the clipper. It is recommended to use technical wipes that do not produce lint. If you use an old rag, it will leave a lot of small particles, fluff, which will get into the brakes and can cause leakage or dirt.
Be sure to wash your hands before installing the pads in the system. You have pumped the brake system and most likely you have brake fluid residues on your hands. You don’t want to get the pads dirty by inserting them into the brake system. When working with the brakes, your hands must be clean, as oil, grease, brake fluid will contaminate them and you will need new pads. As you know these disc brake pads can be expensive.
Hydraulic bicycle brakes
Hydraulic brakes. fluid hose instead of cable
The mechanism of action of hydraulic brakes is very similar to that of their mechanical counterparts (disc and rim brakes). The main difference is that mechanical brakes use bicycle cables, while hydraulic brakes use a special hydraulic line instead of a cable. This hydraulic line connects the brake levers to the brake itself, which can be a mechanical disc or V-brake pads.
The bottom line is that there is oil or brake fluid under pressure in the hydraulic line. There are cylinders at both ends of the hose. When you press the brake lever, the brake cylinder transmits force to the brake line, which activates the other cylinder at the other end of the tube, which in turn activates either the rim or disc brake, whichever you use. If you use brake fluid inside the tube, you must take into account the fact that this fluid is poisonous and to paint coatings (corrosive). Therefore, this liquid can be replaced with oil.
Installation of hydraulic brakes
To apply the rear brake to the frame, the brake hose must be disconnected because the brake hose will need to be threaded through the mount. Usually the hose is simply attached to the frame. Remove the pads before working with hydraulic disc brakes, as the brake fluid will spill and dirty them during operation. Make sure you have clean hands before starting. Remove the pads, move the discs and pads away from the bike and then you can disconnect the brake line and pass it through the frame again connect and bleed the system.
Cam and compression brass fitting with nut.
Disconnect the hydraulic hose from the discs and pads. Keep them away from the work area. When the hose is pulled out, the brake fluid may become contaminated. So, if you now bring the end of the hose closer and take a closer look, you can see the cam and the compression fitting. The brass fitting is used to prevent the plastic hose from shrinking from the heat and from jumping out of the cam when the system is very hot, that is, the cam and the fitting simultaneously hold the hose in place when it heats up.
Before threading the brake hose into the mount, make sure that the hose gasket fits your bike. Fork manufacturers today require that the hose does not rub against the crown or the leg of the forks otherwise they will void the warranty. Do not leave the hose too long so that it does not touch the crown or it could damage it with constant friction. Pull it carefully, but so that the steering wheel does not break the hose at maximum turns. Pull along the frame, through the holes, straight to the mount, and from there outward to the clipper. Now you can attach the clipper to the frame.
Now we need to cut the hose, leaving a small loop. Remember that the hose is inserted into the machine, so do not cut it too short at the very entrance to the machine body. It is necessary to add 7-10 millimeters to the length. When you have cut the hose, you can put in a new olive and compression fitting. First, we put on the nut that holds them, then the clamp. There are directional clamps, so it is very important to read the manufacturer’s instructions for your particular disc brake system. Some clamps have a chamfer. When the clamp is on, insert the compression fitting. It should fit snugly and clamps should be used to hold the hose firmly without damaging it. Then take a hammer and drive in the fitting. When the fitting is in place and the clamp is ready, put the nut on, lightly lubricating the clamp and nut so that everything fits into place. Tighten it by hand and when you think that it will stop push the hose all the way into the machine, now you can tighten the nut and again try not to overtighten, it is better to use a special tori wrench. To tighten the compression nut to the desired value.
If the nut is tightened properly, you can start pumping.
- Read everything you want to know about bicycle braking systems in this article.
- Find out why the roller brake is ideally modulated and who is best for you
Adjusting the hydraulic brake pads
If you have correctly adjusted the clipper and the brake disc is exactly in the center, but still clings to the pads, this usually means that one of the valves protrudes from the body more than the other. Once you are confident that the disc is exactly in the center of the clipper, you can do one trick to even out the distance between the pad and flange. It will take two people here. One should press the disc against the valve, which is too protruding, and the other will work with the pads, sliding and extending them. The valves will align. Due to the pressure of the disc, one valve works more than the other, that is, with the help of the disc, we press one valve into the body, while the second moves further. This is how we align the valves using a disc. But don’t push the disc too hard, you can bend it.
- Bicycle brakes are not a luxury, they are a must. Which brakes you put on your bike will determine the degree of your personal safety while riding.
- Cost for popular hydraulic brake models: www.velosipedinfo.ru/diskovyie-tormoza
I want to say that using hydraulic brakes, if the speed of the bike is high enough, you need to be extremely careful so that it does not work out as on
Hydraulic brakes on the bike do not brake
Basic types of bicycle brakes.
There are three main types of bicycle brakes: rim, disc and drum. Rim and disc are subdivided into mechanical and hydraulic. On mechanical brakes, the force is transmitted to the pads by means of a cable, on hydraulic ones. using a special liquid.
Rim brakes. there are several types: V-brake, cantilever and clamp-on. The most common are V-brakes. Rim brakes get their name from the fact that the brake pads directly compress the wheel rim.
Disc brakes. the main difference is that the pads do not brake the wheel rim itself, but the brake disc (rotor), which is located on the hub.
Drum brakes. such a brake is located directly in the rear wheel hub, and braking occurs due to the rotation of the pedals in the opposite direction. Fits on single speed bicycles or bicycles with planetary gear shifting.
Disadvantages of V-brake brakes
Mechanical and hydraulic brakes are structurally very similar and, at first glance, an inexperienced cyclist may not even distinguish between them. But there is one significant difference in them, thanks to which they differ from each other. They differ in that by means of which the force is transmitted to the brake pads.
In a mechanical brake, the force from pressing the handle is transmitted by means of a metal cable. The cable is pulled through special protective shirts from the brake lever to the brake mechanism and, when the handle is pressed, it is pulled, squeezing the brake pads.
How to fix a Shimano hydraulic brake without bleeding it.
The advantages of a mechanical brake include maintainability and easier maintenance.
In a hydraulic brake, the force from pressing the handle is transmitted using a special brake fluid. The fluid is hermetically filled with a hydraulic line (something similar to ordinary cable jackets), which runs from the brake lever to the brake pads themselves.
The hydraulic brake has several advantages:
You can always contact a specialized workshop for mounting / dismounting a bicycle disc brake.
How to adjust hydraulic disc brakes
Although hydraulic brakes are called self-adjusting brakes, it is sometimes possible to notice a rustle or squeak that they emit during the braking process. In this case, adjust the disc hydraulics of the bike. Also, a similar procedure is necessary on a new bike if the brakes were set incorrectly from the factory.
- Slightly unscrew the bolts that fix the caliper to the adapter.
- We clamp the brake lever and fix it with electrical tape, rope or other improvised material.
- We make sure that the rotor is clearly in the middle of the caliper slot, and the brake pads are extended equally on both sides. If this is not the case, then you can set its position by slightly pressing on the rotor from the desired side. Due to pressure, the brake fluid will be evenly redistributed between the pistons.
- After that, we tighten the mounting bolts and remove the electrical tape from the brake lever.
After you have adjusted the hydraulic disc brakes, turn the wheel and check for friction. If you observe intermittent shuffling, then this is a signal that your rotor is slightly bent. To eliminate this malfunction, it is necessary to determine the place of friction, and on which side of the pads the rotor clings. Then rotate the rubbing area 180 degrees from the caliper and gently push in the opposite direction. This should be done very carefully in several passes, with each of which add force until friction completely disappears.
Setting up hydraulic disc brakes is shown in the video below.
Remove dirt and oil from brake pads and rotor
During cycling, over time, dirt and oil accumulate on the rotor and brake pads, which impair the braking performance of disc mechanics or hydraulics. Therefore, before adjusting the disc brakes, remove it from these surfaces. For this, you can use fine sandpaper. Remove the rotor from the wheel and clean the surface on both sides in a circular motion. We perform the same operation with pads (of course, on the one hand). Do not be too zealous, it is enough to remove a thin layer. After you have completed this procedure, try not to touch the pads and rotor with your hands or oily objects.
How to set up and adjust disc brakes on a bicycle
Many riders, first encountering hydraulic or mechanical disc brakes on a bicycle, do not know how to properly set, adjust or replace consumables. Many consider their design to be much more complex than V-brakes. but it is not so. Technologically, good bicycle disc brakes, especially if they are hydraulic, are more advanced than v-breaks and perform significantly better at their tasks, but remember that this is not the case for cheap mechanics. Next, we will look at how to properly install and adjust disc brakes yourself at home. But we will start with the design features and differences between disc mechanics and hydraulics. And then we will touch on all of the above points.
First of all, we unscrew the brake rotor from the hub and check it for deformation. This can be done by placing it on a flat surface (glass, mirror, etc.) and inspecting it. If the rotor is loose, it should be aligned before adjusting the disc brakes. If the deformation is insignificant, then this operation can be performed when adjusting the brakes.
How to set up mechanical disc brakes on a bicycle
Adjustment of the disc mechanics is required to be done: after installing new pads, cable, rotor or other brake components; in the case when the rotor rubs against the pads; when it is required to eliminate a large brake lever travel, etc.
- We check the tightness of the bolted joints at the points of attachment of the adapter to the frame and the rotor to the bushing.
- Loosen the lock nut and tighten the cable tension adjustment on the handlebar until it stops minus 1-1.5 turns. Then tighten the lock nut. We do the same on the adjustment, which is located on the caliper. Next, unscrew the cable retainer, and, pulling the cable by hand, tighten the retainer bolt back. (If you have already done these operations when installing a new brake, then you do not need to repeat these steps).
- We loosen the bolts that attach the machine to the adapter (for easier setup, you can remove it completely).
- We adjust the position of the fixed (static) and movable shoe. The purpose of this procedure is to achieve an equidistant position of the pads from the center of the caliper slot so that the rotor can fit between them with minimal clearances. To adjust the fixed shoe, loosen the locknut (if any), and rotate the bolt that adjusts its position. To adjust the movable one. rotate the cable tension adjustment on the caliper. After the distance is set, tighten the static block retainer. If for this procedure you removed the machine, then you should install it in place, but do not tighten the mounting bolts.
- We set the correct position of the caliper relative to the brake disc. To do this, the bolts that attach it to the adapter must be loosened so that it can walk relatively easily left and right. We press the brake lever all the way and fix it with electrical tape, wire, rope or other improvised means. Next, slightly wiggling the caliper with your hand, screw it to the adapter, alternately tightening the bolts.
- After performing the above operations, in 80% of cases the rotor will shuffle against the deck (s). We determine which of them it clings to, and adjust the distance by adjusting the cable tension on the caliper (in the case of friction against the movable block) or by rotating the bolt (if rubbing against the static one). The clearance on both sides should be minimal, at which the rotor does not touch the pads.
You can watch a detailed process of setting up disc mechanical brakes in this video.
There are cases that after setting up the mechanical disc brakes of a bicycle, the rotor “strikes” against the pads in one (or several) places. This suggests that you have it slightly deformed. In this case, you need to align it. This can be done directly on the bike without removing the rotor. Determine the place where it touches the pads by slowly rotating the wheel. Pay attention to which side the rotor is deformed. Then, we turn this section so that access appears to it, and we bend it in the opposite direction from the place of friction. Be careful not to make it worse. Do not apply too much pressure to the rotor. It is better to repeat this operation several times, gradually adding pressure.
What to do before adjusting the brakes
If you need to adjust disc brakes that have already been in operation for some time, then before making the adjustment, it is advisable to carry out the following preparatory work:
Check the condition of the brake line for leaks
This item is exclusively for hydraulics. Before adjusting the hydraulic disc brakes of the bicycle, inspect the brake hose for damage (it is advisable to replace it, even if the damage is minor), and also check that there are no oil / brake fluid leaks at the joints of the hydraulic line with the caliper and the master cylinder. Another place where the brake fluid can poison is the rod going from the brake lever to the piston (if the cuffs are leaky). Well, after removing the brake pads, check the absence of leaks on the caliper.
Principle of operation
The rider, pressing the brake handle, builds up pressure in the hydraulic line, which displaces the brake fluid from the master cylinder. Then it hits the slave cylinder.
Under the influence of pressure, the pistons bring the brake pads together, and their friction against the rotating shaft leads to an instant blocking of the wheels.
CLIM 8 CLARK`S
Reliable, budget model, adapted to various weather conditions.
- Hydraulic hoses are reinforced with para-aramid fiber and metal;
- six-cylinder caliper design;
- increased weight;
- difficulty in installing the system (requires additional adjustment);
- handle design.
The best hydraulic brakes for a bike
Bicycle companies are gradually switching to disc brakes. According to experts, they perform well, they work even in damp weather, they are durable, reliable, and, according to forecasts, in the near future they can displace other types of brake systems.
How to Maintain Hydraulic Brakes on a Bicycle. Bleeding Forward and Reverse
Modern bicycles can be equipped with various braking systems. Each has its own advantages and disadvantages. Cycling enthusiasts have to make choices that depend on many factors.
Of the existing types, hydraulic braking systems have become very popular in recent years. Bicycles with “hydra” are now in trend and are in demand among those who like to ride with the breeze.
Bridging the gap in mechanical disc brakes
If you have a mechanical disc brake on your bike (the approach to hydraulics is somewhat different), then you can remove the gap, or rather, eliminate some curvature of the brake pads, by properly fixing the caliper. Provided that the possible curvature of the disk is preliminarily eliminated.
For repairs, you will need a fifth hexagon, as well as another person who will press the brake lever at the right time. The procedure is as follows:
2 Reasons Why Your Disc Brakes Don’t Work
- loosen the mounting bolts on the caliper, which secure the latter to the adapter;
- forcefully press the brake lever;
- the pads will press against the disc and the caliper is shifted as needed, and the curvature is eliminated;
- the caliper will need to be rotated in this position without releasing the brake lever. until there are no traces of curvature left. Like this. And no gap!
And if the caliper does not have an adapter, then you will need a set of calibration washers and, again, a fifth hexagon for twisting the bolts (although on some brakes you can do without a key and twist the bolts directly by hand).
The bolts are twisted neatly on both sides of the caliper, and the pads are brought close to the disc. You will get a barely noticeable gap, which will not prevent the disk from spinning.
Hydraulic brake device
Any hydraulic brake consists of at least two cylinders with pistons, connected by a line, or, more simply, a hose that can withstand high pressure. When the cyclist presses the brake lever, the piston displaces the brake fluid from the master cylinder and transfers it to the slave cylinder located in the machine. Here, under the influence of pressure, the pistons begin to extend and press on the brake pads. And already due to the friction of the pads on the rotor (brake disc), braking occurs.
The cylinders in the brake machine are always larger than those in the brake lever. Due to this, in accordance with the law of hydraulics, the working brake pistons press on the pads several times more force than the cyclist does by pressing the handle. Also, this law works here due to the fact that two cylinders are installed on the brake machine, or even all 4, 2 on each side.
Pumping. the final stage of the repair
When the entire system has already been completely sorted out and assembled, it remains only to fill in the brake fluid and properly pump the hydraulics. The system is pumped in order to expel air bubbles from all pipes and cylinders, which prevent the hydraulics from working correctly.
There are a lot of ways how the hydraulic brakes of a bicycle are pumped. Anyone can do this at home, if they know how to handle tools at least a little. Some use syringes, while others use old and proven methods. Consider the simplest and most time-tested option.
To bleed the brakes, you will need the following components:
- a transparent tube, suitable in diameter to the bleed bolt;
- brake fluid or oil, depending on the specific system;
- required keys;
- jar or bottle;
- a piece of clean cloth to keep it clean.
First you need to put a transparent hose on the bleeding bolt, and lower its other end into a jar, where there should be some brake fluid. Next, you need to open the brake fluid reservoir on the handle and make sure that it is at the maximum level. If necessary, the liquid must be topped up.
Attention! The brake fluid is unique for each bike model and cannot be mixed or replaced.
After that, you can start pumping the disc brakes on your bike. Pressing the brake lever several times, you need to fix it in the pressed state and at the same time unscrew the screw for bleeding on the brake machine. In this case, you can observe how air bubbles will go out of the tube. After that, the screw must be tightened immediately, and only then you can release the handle and swing again.
This procedure must be repeated several times until the whole system works as it should. This can be felt by the stiffness of the brake lever.
And one more way to pump the hydraulic line for the lazy:
Symptoms of a hydraulic brake malfunction
The first symptom of a malfunction of such bicycle brakes is that it starts to slow down on its own. This can be explained by the fact that air has entered the brake system. This could have happened due to the fall of the bike, a low level of brake fluid in the reservoir, or when the hydraulic circuit is open.
Since air tends to compress, unlike liquids, when it enters the system, it works like a gas spring. That is, the air creates the pressure of the brake fluid, which activates the brakes.
Also, the braking system can engage in such self-activity, in case of jamming of the working piston. And the reason for this is the ingress of water into the hydraulic system.
And, of course, the brakes urgently need to be repaired if the brake lever is not as elastic as before, or the hydraulics no longer responds to the cyclist’s command to stop the vehicle.
Troubleshooting and repair
To understand what exactly happened to the braking system of your faithful two-wheeled friend, you first need to do some experiments. The first step is to remove the wheel where the problem appeared. Next, you need to clean the brake machine well, the easiest way to do this is with a toothbrush. Well, the main goal is to remove the pads.
When access to the working pistons opens, you need to press them in with a screwdriver, and then gently press the brake lever. Both pistons should move forward. If one of them is stuck, you need to use a repair kit to eliminate the malfunction. Also, the piston system must be carefully inspected for leaks, if they are present, then the cylinder-piston group is worn out. As a rule, in this case, the pistons or special sealing rings on them are changed.
In conclusion, you need to carefully inspect all hydraulic line. There should be no kinks, dents or other damage on it. If present, the hose must be changed.
Adjusting and bleeding hydraulic bike brakes
Hydraulic brakes are used primarily on bicycles where precision, responsiveness and reliability are required. First of all, these are heavy, massive mountain bikes designed to overcome steep slopes and climbs. Also, hydraulics have become an integral part of high-speed bicycles, as it allows you to very accurately and in the shortest possible time reduce speed.
The principle of operation of hydraulic brakes is very similar to mechanical brakes, where the brake pads are operated by a cable. The only difference is that in the hydraulics, instead of cables, brake fluid is used, and levers and eccentrics replace the cylinder-piston groups. Thanks to this approach, the frictional forces in the system are significantly reduced, and this increases its service life.
Despite this, hydraulics also has disadvantages, first of all, it is difficult to repair in case of breakdown. For example, if the hydraulic line breaks down, the brakes will not work in the field. The most that is possible with the tools is to bleed the hydraulic brakes.
When repairing hydraulics on a bicycle, it is unacceptable for brake fluid to get on the pads or rotor. If this happens, the elements must be cleaned immediately with fine sandpaper. Otherwise, the brake pads will not work efficiently and quickly fail.
It is also important to know that brake fluid is poisonous and can be harmful to health, therefore it is not recommended to get it on the skin. Eye contact should be especially avoided. In addition, it is a good solvent. easily corrodes the bulk of paints and varnishes.
Types of hydraulic disc brakes
The main difference between a disc brake and a conventional rim brake is that braking occurs by clamping the brake disc, rigidly fixed to the hub, with brake pads, which are fixed at the rear on the frame and at the front on the fork stays.
The design of the main brake cylinder can be different, and depending on this, hydraulic brakes are divided into the following types:
- Single piston;
- Twin-piston with opposed pistons;
- Two-piston with floating pistons;
Mostly used two-piston with opposed pistons. There are also single-piston ones, but due to shortcomings, they were almost completely replaced by two-piston ones. Complex multi-piston systems are used mainly for downhill, where power plays a decisive role, rather than simplicity of design.
Due to the type of fluid used in hydraulic systems, brakes can operate on brake fluids and oil. Each of them has its own advantages and disadvantages, but there is no unequivocal opinion on this matter. The caliper can be monolithic, which makes the structure stiffer and lighter, and composite. cheaper in price, but more difficult to maintain.
The hydraulic disc brake is very reliable, but it is not easy to repair and adjust in the field. True, to bring the hydraulic brake to a coma state, you need to try very hard.
There are some problems associated with the fact that disc hydraulics have a very small gap between the pads and in the presence of heavy dirt, the pads are subject to increased wear. But mechanics have no advantages in this case, since worn-out pads cannot be adjusted on the fly, while hydraulics are automatically supplied in the course of wear.
They are more expensive than rim ones, slightly increase the load on the hub during braking, although this is a controversial issue. We will not delve into the details of the drive in detail, since this is a separate topic for conversation, but for now, let’s start considering what the manufacturers have prepared for those who want to put hydraulic brakes on the bike.
Advantages and disadvantages of hydraulics
Dosing accuracy and the speed of response of the mechanism to pressing the handle are two main qualities that have led to the widespread use of hydraulic brakes. These are far from the only advantages, but they are the ones that made the downhill athletes turn to hydraulics.
The excellent endurance of the hydraulic brakes also played a role in the migration of hydraulics to the bike. As well as the accuracy of actuation, this was a very important quality for downhill.
The reliability of the system has been proven over the years of its use in automobiles. With proper care, hydraulic brakes on bicycles are many times more reliable than mechanics. The heightened sense of the strength of the dosage allows you to manipulate the brakes with jewelry precision. In extreme sports, this is a must.
The disadvantages of hydraulic brakes include the following: The cost of a hydraulic system is much higher than a mechanical one, therefore a bicycle with hydraulic brakes will be more expensive. Complexity of service. The hydraulic system is a rather complex and technologically advanced unit that requires maintenance skills and a clear knowledge of the design and its features. Not every biker is able to independently sort out the system and carry out its high-quality repair. Also, field repairs in the absence of experience can be difficult. Brake pipes and hoses require careful handling. They are quite vulnerable and the quality of the entire system depends on their condition. Also, brakes can be picky about the quality of the brake fluid or oil, so you should make a deliberate choice when pumping.
Most often, hydraulic brakes are used in tandem with disc brakes. Literally a few words should be said about them.
Principle of operation
The brake line is filled with a special oil or brake fluid under low pressure. When the brake lever is depressed, the bicycle brake cylinder displaces fluid from the hydraulic system and it applies pressure to the slave cylinder, which is mounted on the fork or bike frame. In turn, the slave cylinder drives the piston and brake pads, which block the wheel by means of the brake disc. Very simple. Here is a diagram for clarity.
When working with hydraulic brakes, it is worth considering that brake fluid is very toxic and can cause severe poisoning. It also has a detrimental effect on paintwork and plastic parts.
Features of Hydraulic Bicycle Brakes
The vector of action of the brakes, both mechanical and hydraulic, is one. stop. a car. But there are a lot of nuances and questions to both one and the other brake drive circuit. Today we will try to wash the bones with hydraulic brakes.
Their main difference from mechanics is that a hydraulic line is used to drive the brake pads, and not cables. The hydraulics connect the brake levers directly to the brake mechanism. In the role of which can be both disc hydraulic brakes and conventional rim.
Review of the best
Out of a million types of braking systems, hydraulics are increasingly found on mid to very mid-range bikes. As their popularity grows, the price falls accordingly. Therefore, it makes sense to consider converting your bike to a hydraulic braking system. There are many examples, but we will give only two. For contrast.
Shimano unveiled a new collection earlier this year, revamping the Deore line. Nice grips, stable operation of the main brake cylinder gives real pleasure from precise actuation and obedience of the entire system as a whole. A slight rattling of the handle itself darkens the picture a little.
The new range offers a choice of splined or bolted rotor mounting. Shimano Deore comes with two types of pads. rubberized and metallized. The former wear out very quickly. The hydraulics in general are of excellent quality and their 50 is definitely worth.
CLIM 8 CLARK`S. The advantage of these brakes is that for the price of a single cylinder you get a full multi-cylinder hydraulic brake. But miracles do not happen, and you have to pay for everything. The design of the handles is a little alarming, but this is not for everybody. But the hydraulic hoses are reinforced with Kevlar and metal.
The caliper has an interesting six-cylinder design that promises to be reliable. The disadvantages of this system are the slightly increased weight. In installation, they are also not as easy as they seem. during installation, they require careful adjustment of the pads to the discs.
Bleeding the brake hydraulic system
Reasons why you should do brake bleeding:
- when you press the brake lever, it goes out to the grip itself, i.e. has too long a stroke, but at the same time the pads do not move, or do not reach the brake disc;
- the brake lever falls through when pressed or has too little movement;
- when the handle is pressed sharply, after the brake is applied, the handle continues to fall smoothly.
All clear. The reason for the failure of the brake system was the air that got inside. The first step is to find the place where the system grabbed the air. This can be damaged hydraulic fittings, boiling of the liquid due to overheating, a weakened pumping union on the cylinder. After checking the entire system for fluid leaks, you can start pumping.
We always pump the hydraulics on a flat and horizontal surface. The pads should be spread apart so that they do not reach the disc. Next, we unscrew the master cylinder and fix it strictly horizontally. Each system has its own characteristics of pumping, so it is better to do it according to the instructions. The pumping fluid must correspond to the brand indicated in the passport.
Now you should put the cambric on the bleed bolt and immerse it in a container to collect the remaining fluid. We unscrew the cover of the expansion tank, fill in the liquid to the maximum level. Several times smoothly and slowly press the brake lever. Press until it becomes tight. Now holding the handle, unscrew the bleed bolt with a cambric, without releasing the handle. Add liquid to the expansion tank. We carry out the procedure until the handle becomes stiff. We twist the expansion tank and remove the tool. Done, brakes pumped.
So the rumors about the difficulty in servicing hydraulic brakes are greatly exaggerated. Along with some disadvantages, such a system has more advantages. But in principle, the principle of operation of this or that mechanism is not so important to a real biker as the very fact of free movement in space.
Pros and cons of bicycle disc brakes
Before you start identifying the pros and cons of disc brakes, you first need to figure out what they are. In fact, the disc brake mechanism is very simple. To begin with, imagine a wheel and figure out where to the left and where to the right. So, on the left side, near the spokes, there is a disc made of steel, it rotates. Pads are pressed to it due to a special device. And the tighter they are pressed, the more braking will be. That’s the whole secret of the functioning of this device.
A bicycle with hydraulic disc brakes has the following technical features. The master cylinder and piston are located on the steering wheel in the brake lever, it controls the structure. It is connected by a durable sleeve with a power cylinder, which drives the brake pads. The structure is filled with oily liquid, it is sealed. Change and repair will require specific knowledge and tools.
As for bicycles with mechanical disc brakes, the mechanism of their action is the same as for classic bicycles (vibrake, city). The brake pads are pressed against the disc due to the fact that the cable pulls the drive lever.
On hybrid bicycles, the braking system consists of hydraulic and mechanical brakes. The hydraulic part is located on the body, it consists of 2 cylinders (control and power), between them a small amount of oil fluid. The cable due to the lever affects this system and the bike slows down.
Now let’s move on directly to considering the positive and negative aspects of disc brakes. Although the pros and cons are relative concepts, each user has their own, individual opinion on this matter. The comparison can be made as with other types of braking systems. So it is with each other.
At the moment, there are the following types of brake systems: hydraulic, vector, tick, rim, roller, canteliver. The listed systems, with the exception of the roller system, directly affect the wheel rim, therefore they are also called “rim” systems. Rollers are located on the left side of the wheel hub and work in the same way as drum brakes. They are not very common due to their huge weight, size and incompatibility with most suspension forks.
The main advantages of disc brakes:
- abrasive and steel discs have significantly higher friction values compared to the friction of a pad on an aluminum rim
- weather and road conditions do not affect them
- long service life of rims
- long service life of discs and abrasive pads
- high level of braking
- ability to function regardless of rim damage
- the steel disc is not affected by high heating at the time of braking (especially in the mountains)
- slow down taking into account the applied efforts
- are regulated and configured once
- significant cost
- considerable weight
- high requirements for the degree of rigidity of the damping torsion fork (not any is suitable)
- specific installation, especially for the hydraulic system
- increased load on the wheel spokes
- complex process of changing abrasive pads
What to give preference to, you ask after reading the above material. In principle, this is all very individual and depends on both the financial capabilities of the person and his level of riding, where and how he will use the bike.
I would also like to draw your attention. the cost of disc brakes is higher than that of conventional brakes, while the cost of a bike with different systems is the same. That is, a bike with a classic brake has better equipment. But at the same time, in terms of braking performance and even appearance, disc brakes are many times higher than usual.
As for the features between the types of disc brakes, they depend on the design characteristics. Hydraulic ones are in the first place compared to the rest. They are more powerful, they have no backlash, they are easy to adjust and brake forces, and there is very little surface that rubs. Mechanical ones have backlashes and more surface that rubs, they also have more wear. But they have a lower cost and are more reliable, and they can also be easily repaired in any conditions. Hybrid in all characteristics are at an average level.
Finally, I would like to summarize everything that has been said. If you prefer active and extreme rest, drive on different roads at high speed and are not limited in money, then in this case you need to choose hydraulics. In the case of a limited budget, as well as if you prefer reliability and easy repair, then you need to take a mechanic or a hybrid.
In any case, everyone chooses independently and individually.