Features of disc brake systems
The disc brake consists of a rotor (steel disc) and a caliper. The rotor is mounted on the wheel hub. As a rule, it is placed on the left side. A caliper is a device that helps to compress the disc with brake pads. The transmission of braking force occurs using a cable or hydraulic line.
Caliper brakes have a U-shaped arm mount. Cantilever systems are mainly installed on cyclocross bikes exposed to massive mud. Hydraulic brake systems for braking transfer fluid through the hydraulic line from the handle to the brake pads.
We invite you to familiarize yourself with a short video instruction on how to set up V-brake brakes.
To date, the following models of rim brake systems are distinguished:
The most common are V-brake models. Their name reflects the V-shaped mount of the levers.
Mechanical disc brake device:
All disc braking systems existing today can be divided into several categories:
Installation and adjustment of v-brake brakes | over bumps
How To Stop Your Brakes Rubbing | Mountain Bike Maintenance
V-brakes can work just as well, and depending on the model, even better than disc brakes, and with the correct setting and good brake pads, it will.
Their design allows you to adjust the pads in almost any plane, which cannot be achieved with cantilever and caliper brakes, as well as v-brakes, which are rim.
They cost much less than disc brakes, weigh much less and adjust v-brakes is simple.
The advantages of drum brake systems include a high level of resistance to the negative effects of water, dirt and other aggressive media on their body. Does not affect rim wear.
Among the shortcomings, one can single out a large mass, low braking power, the possibility of overheating during a long descent from a hill. In conditions of variable “brake” and “gas” it is very difficult to maneuver.
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.
The springs that are part of the mechanical rim brake system are also responsible for the distance between the wheel and the block. But, unlike a nut with a cable, they allow you to adjust the distance down to a millimeter. That is, more precisely. The spring tension can be changed with a single bolt that is screwed on and off every now and then. This bolt is located on both sides of the brake. Therefore, when a situation arises that one side touches the rim, and the other is separated, you just have to turn the bolt. and everything will fall into place. When this element is twisted, the spring becomes “harder”. Consequently, the distance will increase. If you unscrew the bolt, the spring will weaken. From this, the distance will decrease. So, by adjusting each element, you can achieve perfect accuracy.
Checking the readiness of the system for adjustment
- The adapter to which the caliper is attached is well secured to the frame or fork (bolts are tight).
- The already tested rotor is securely fixed with screws on the hub.
- The wheel is mounted on the bike, the eccentric / nuts are tightened.
- The lamb for adjusting the cable tension is unscrewed no more than 1.5 turns (located next to the handle or caliper).
- The cable is fixed on the movable arm of the machine.
Adjusting the rear brakes on a bicycle
In theoretical terms, everything seems to be clear. Three parameters, three actions, and only one result. well-tuned brakes. Once again, this is in theory. In fact, it is difficult for beginners to do everything perfectly. Adjusting rim brakes on a bicycle is a delicate thing. So you need to be patient first.
So the first step is to adjust the pads. They should be parallel to the rim on both the rear wheel and the front.
Especially do not tolerate the striking of this element on the tire. A couple of kilometers. and the rubber will be frayed to holes. It is undesirable for the block to also go beyond the boundaries of the wheel. From this, it is quickly erased, but there is no desired effect (good inhibition). Therefore, it is so important to correctly adjust the position of the brake pads. Adjusting a mechanical brake on a bicycle begins with the selection of tools. You will need: a hexagon, a screwdriver and a 12 key. For rubber clamps, you should take only a hexagon. It is worth starting by holding the brake lever. This will push the pads against the rim. After examining the situation, you can immediately see where something is wrong. Use this tool to loosen the washer. Then, while also holding the brake lever, align the rubber clamp in the desired direction. The same is worth repeating on the other side. This is just the first step towards a perfectly tuned brake.
How to check and adjust the brakes
There are clear instructions for checking and adjusting the brake system of a bicycle. If you adhere to it, then the whole process will take little time and will be effective.
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. It is worth considering one nuance. 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.
Varieties and models of bicycle brakes
Brake adjustments on a bicycle can vary. In each situation, it is worth looking at the type of braking system. Most often, cheap bicycles are equipped with mechanical rim brakes, or, as they are also called, V-brakes.
How To Adjust Cable Disc Brakes
If the pistons extend the pads unevenly
If one piston does not work freely, it is most likely clogged. In this case, it is worth removing the wheel, and then removing the pads from the caliper. You will need a clean metal plate with holes for the mounting pins.
Using it, move the serviceable piston and press the brake lever so that the clogged one can get out. After that, it is necessary to wipe it with a clean cloth and apply mineral oil (non-aggressive to rubber) on its surface. Then put the piston back, wiping off excess oil. often the rear brakes on the bike get dirty, probably due to the fact that there are more mechanical parts and the drive.
How do I adjust the brakes on my bike? Rear brakes on a bike
If the hydraulic brakes on the bike were installed for a long time and began to work worse, then it’s time to adjust them. First, we install the disc on the wheel hub, you need all the bolts to be evenly and carefully tightened.
Centering the caliper in relation to the disc
Now on to the big deal: how do you adjust the brakes on your bike for the first time? We want the disc to fit exactly in the caliper. To achieve this, washers are installed between it and the frame. They come in different thicknesses, so the installation is carried out by the selection method. This is a time-consuming process because tightening the bolts will push the caliper much harder against the frame than if you simply press it down by hand. Having substituted the washer, you constantly need to tighten tightly and watch how the caliper is located in relation to the disc.
However, hydraulic brakes on a bike are much easier to adjust. For this, there are adapters that are located between the rear triangle of the frame and the caliper.
You must first screw on the adapter, and the caliper is already on to it. However, the bolts should not be tightened yet, they should just fix everything. After that, you need to clamp the brake lever and watch how the pads clamp the disc. When he presses, the caliper will go to his workplace.
For greater reliability, it is worth twitching the wheel a little so that everything is fully in place, and tightening the bolts. When everything is fixed, you need to bleed the brakes. This is done by sharply pressing the handle 15-30 times. This is done to ensure that the pads are in the ideal braking position.
When the pistons cannot return to their original position?
The pistons may not return due to clogging, then you need to do the procedure described above. It could also be the brake lever, or dirt can get into it. Then you will need to disassemble and clean it. serious problem. this is when the brake oil system has leaked. If the leak is not strong, then it is worth changing the gaskets at the joints. In case of more complex breakdowns, it may be necessary to replace the brakes.
It so happens that the brake lever falls through. This can occur when air is trapped in the hose. Bleeding the brakes will help fix this. However, this can also be due to a breakdown in the hydraulics. Depending on the location of the leak, you need to replace the gaskets, the worst option. brake line replacement.
If the disc is bent
If the disc is bent, how do you adjust the brakes on the bike? It needs to be aligned. This can be done with a special tool, or you can use an adjustable wrench. It is necessary to determine the curvature zone and install an adjustable wrench in its middle part, having previously placed a piece of cloth so as not to scratch the surface. Thereafter. bend in the required direction.
If you need to change the brakes
Now let’s look at what to do when we change the brakes for a bicycle. To put them on, the hydraulic line must be disconnected, because it will need to be pulled through the mounts. If the brake hose is attached to the frame, you do not need to disconnect.
We will consider a more complex option and will know exactly what to do in this case. Disconnect the brake hose and thread it through the mounts. But before doing all this, you need to disconnect the pads to keep them clean. After all, working with oil is dirty, and you can accidentally stain the pads and disc.
Disconnect the hydraulic hose and see the cam that is inserted into it, and the compression fitting (it looks like a ring put on top). The cam is designed to prevent the plastic hose from contracting when the system is very hot. And the fitting holds it in place.
To extend the hose, the end must be cut off along with the cam and fitting. The cut must be clean and even. To do this, it is better to use a special cutter, with which you can quickly and efficiently carry out everything. If there is no such tool, then you can use a razor or knife and cut carefully on a flat surface.
When the brakes are not pressed, the pads rub against the disc
It so happens that everything seems to be adjusted, ideally installed, and when checked, it shifts a little, after which the pads touch the disc. How do you adjust the brakes on the bike in this case? Determine which of the pads is rubbing. After that, we loosen the bolts on the adapter and shift it towards friction. We also look to make the block parallel to the rotor. And so by the selection method we achieve the perfect result.
When both the left and right pads cling to the disc, you need to adjust the hex on the brake lever. It must be unscrewed until the pads fit properly. It is designed for just such an adjustment. After all the settings, it is worth checking again how everything works.
Setting and adjusting mechanical
Immediately after installing a new brake system, it should be properly adjusted. There can be many reasons for adjustment: friction of the disc on the pads (often accompanied by a typical “whistle”), too loose brake lever, etc.
- All bolts and fasteners are checked. All bolts connecting rotor and hub must be tightened well.
- Loosen the lock nut completely and start tightening it, leaving about 2 turns until it stops. We carry out similar settings on the caliper. Then we unscrew the latch and tighten the cable by hand, tightening the latch in place. Caliper Retainer Adjustment
- Loosen all bolts that secure the device and adapter. If it is difficult to get to this component, then the machine can be completely dismantled, adjusted and installed back.
- The movable and immovable parts of the block should be adjusted so that they are located exactly relative to each other. All parts of the pad must be at the same distance from the caliper.
- Likewise with the caliper. it must be precisely aligned with the disc. The mounting bolts should be completely relaxed, set the caliper level and tighten the bolts.
- Almost always, after all these actions, there is inappropriate friction between the disc and the pads. It is very easy to fix this by completing the mechanical brake adjustment. By adjusting the tension of the cable on the caliper (if the rotor rubs against a moving shoe) or rotating the locknut (in the case of friction against a stationary one), you can achieve not only the ideal placement of the rotor relative to the shoe, but also the optimal stroke of the brake lever.
For those who are afraid of hydraulics, assuming that its design is very complex and borrowed from cars and motorcycles, we immediately inform you that hydraulics are practically no different from disc mechanics, it is simply a slightly more advanced design. Between the handle and the rim is now not a cable, but a hose with a special brake fluid (either DOT4, or mineral fluids).
- brake lever;
- brake fluid reservoir, cylinder, piston;
- hydraulic line;
The master cylinder is the main component that distinguishes the product from the mechanics. It is arranged quite simply. a reservoir with a tight lid, inside which there is a liquid, a piston that creates pressure and sends the liquid through the hydraulic line and a spring that returns the liquid and the handle back.
Hydraulic structure [attention type = yellow] Important! Before starting the procedure for adjusting and adjusting the bicycle brake system for yourself, you should prepare and check all the components. This is a necessary measure, since by tightening the lock nut, you can break the cable or break the disc (if, of course, these nodes are in a faulty condition). [/ Attention]
Most novice cyclists, seeing a hydraulic or mechanical disc brake in front of them, do not know what to do with it. The whole reason is that many people mistakenly think that the disc type brake is much more complex than the traditional V-brake. However, this is not the case. their design is not only similar, but also based on the same principles: the frictional force that stops the rotation of the wheel.
Always start with the rotor, i.e. the disc. It must be unscrewed from the main bushing and carefully checked for damage, bends and deformations. During braking, this component is often subjected to torsional loads, which can cause it to deform over time. Place the rotor on a flat surface (preferably a mirror or glass) and carefully check that it is fully seated. If areas are observed in which the rotor moves away from the plane, it should be carefully corrected.
The brake pads should also be checked. Here it is important to make sure that there are no impressive chips and cracks. If the wear level of the pad is significant, it should be replaced. This unit is consumable, there is almost always no point in repairing it.
The cables and cable jackets are the most important part of the braking system. Firstly, if you see that some of the strands of the cable are torn, then it is time to change the entire cable, since the place of local damage will become a weak link and, soon, the cable will burst in this place. Bursting the rope with a strong force, i.e. at the moment of fast and complete braking, most often. extreme. Therefore, a damaged cable, more often than not, bursts exactly when it is most needed. Holes in the shirts of the cable are a bad sign, most likely. the cable in this place will, sooner or later, be torn.
A prime example of a working cable that should be replaced immediately
If the brakes are hydraulic, the hydraulic cutter line must be carefully inspected to ensure there are no leaks and, if necessary, the brake fluid must be replaced.
[attention type = red] Important! All dirt should be removed from the disc and brake pads. Dust and dirt are source of corrosion, and corrosion is a potential weak point. [/ Attention]
This type of system is simple enough:
- brake handle;
- control system equipped with a lock nut;
- a system that allows you to adjust the brake lever;
- cable and his shirt;
- caliper. tensioner;
- mechanical brake shoe;
The brake lever should be installed on the steering wheel: the right one, traditionally, serves to brake the rear wheel, and the left one. for the front wheel (unlike motorcycles, in which it is the other way around).
The handle is installed using special clamps, it is she who is the transmitter of effort from the fingers of the hand to the brake disc. The adjusters help to change the tension of the cable, the lock nut is the main adjustment tool. The more it is twisted, the tighter the cable is and the more sensitive, accordingly, the entire brake system.
In simple terms, the mechanical system is designed in such a way that by pressing the handle, you simply tighten the cable, which twists the caliper and, thereby, presses the pad against the disc, which transfers braking to the rim disc of the wheel.
Mechanical system design
In fact, there are two ways of adjustment. the brake lever adjuster to the grip and the lock nut itself, which is able to tighten and loosen the cable.
[attention type = green] Are you worried about squeaking brakes while driving? Then the article will be useful to you: “Why disc brakes squeak and how to fix it.” [/ Attention]
Setting and adjusting disc brakes on a bicycle
The days when bicycles could be stopped by reverse pedaling are long gone, now two-wheeled vehicles are equipped with both front and rear brakes. To understand how to adjust disc brakes on a bicycle, you should know how they work.
Setting and adjusting hydraulic
With hydraulic systems, not surprisingly, things are somewhat simpler. They are self-adjusting, since instead of a cable, the tension of which can change, there is a hydraulic line, where the liquid is, most often, at constant pressure.
Despite this, friction of the pads on the rotor, “squeak” during braking also occurs. The setup procedure is as follows:
- Unscrew (not completely, only 1 turn) all the bolts that secure the caliper.
- Fix the brake handle with a rope or tight bundle (you can use electrical tape, but there are traces after it). Fixing the handle
- We observe that the rotor is in the center of the caliper clearance. In this case, the brake pads must protrude equally on both sides. If this cannot be done, then you can help yourself by pushing on the rotor from the other side. Pressing leads to an even distribution of the brake fluid between all pistons.
- We fix the bolts and remove the retainer from the brake handle.
After adjustment, you need to turn the wheel and make sure that there is no friction between the pads and the rotor. If there is friction, but it is interrupted, then the rotor is not parallel to the wheel rim, which means that it is deformed.
Adjusting the braking system at home is easy enough. The main thing is to understand the structure of the system, to carry out all procedures calmly and slowly.