Rear brake not working on bike

Roller brakes

Many experts classify roller braking systems as drum brakes. But they have a slightly different principle of pressing the pads against the drum. Roller brakes were invented at the end of the last century and should have become worthy competitors to disc models. But due to their design features, their use was limited, which affected the level of production. Among the advantages are: power, ease of use, a high level of protection against moisture, snow, dirt.

Types of brakes on a bicycle

A bicycle is a power-driven vehicle. It is used to move around the city, when descending a steep pass and during competitions. In such cases, reliable and high-quality brakes are essential. Experts advise before using the bike to check the health of the braking system, which ensures a comfortable and safe movement.

Hydraulic disc brake

Hydraulic brakes for stopping a two-wheeled vehicle transmit brake fluid through a hydraulic line. As for mechanical models, here braking is carried out using a cable.

If we talk about the advantages of disk systems in relation to existing counterparts, then it is worth noting their ease of use. Due to the fact that they are mounted in close proximity to the center of the wheel, during driving, the brakes practically do not clog. Unlike rim models, disc brakes allow the cyclist to smoothly adjust the braking force. As practice shows, disc brake systems rarely fail and do not really need maintenance. In addition, they do not affect the wear rate of the rim.

An example of setting up a disc brake, front and rear derailleur on a bicycle can be found at

Like other vehicle components, brake disc systems, in addition to their advantages, have their own disadvantages. Here you can note the high financial costs during the service. Despite the fact that disc brake systems have a long service life, if a malfunction occurs, they will require a considerable amount of money to fix it. It must be said about the weight of the disc brakes. In many disciplines, this indicator is of great importance.

Mechanical disc brake device:

All disc braking systems existing today can be divided into several categories:

  • Hydraulic;
  • Mechanical.

Rim brakes: advantages and disadvantages

For a long period of time, beginning in the mid-90s, there was practically no alternative to rim braking systems. They were installed on all bicycles produced. And such models cost a lot of money. But since the mid-2000s, rim brakes began to be supplanted by disc counterparts. But this does not mean that they are outdated, since to this day rim braking systems are installed on a large number of two-wheeled vehicles.

So, from the name it is clear that these brakes act on the wheel rim, thereby slowing down its movement. As a rule, they are used in the production of road racing models. Basic principle of operation: The brake pads clamp the bicycle rim using several arcuate levers. As for the quality, technical and operational parameters inherent in these braking systems, they directly depend on the perfection of the chosen model. For example, systems from Campagnolo and Shimano make professional components. Therefore, their braking systems will differ from their counterparts in a high level of efficiency, excellent functionality and reliability in use.

Generally speaking, without paying attention to the elite components, we can say that the braking force of the rim systems is small, and they also have mediocre efficiency and modulation.

Drum brake:

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.

Soft Brake Pedal Fix and Bleeding Brakes

Among the shortcomings, one can single out a large mass, low braking power, the possibility of overheating during a long descent from a hill. It is very difficult to maneuver in variable brake and throttle conditions.

Slippery coating

If the road surface is dry and good, then front wheel skid is almost impossible. But on slippery surfaces, this situation is most likely.

When this happens, there is almost no way for the front wheel to get out of the skid. The risk of falling and injury is extremely high. Therefore, in this case, it is better to control the speed of the bike with the help of the rear brake.

Bicycle front wheel puncture

To safely brake in the event of a sudden burst of the front tire or a sudden drop in pressure in the chamber, you also have to use the rear brake. If braking with a wheel that has a damaged tire, this can create conditions in which this tire can fly off the rim = extremely high risks of falling with the ensuing consequences.

When to use the rear brake on your bike

In 95% of cases, cyclists use only the front brake of the bike. In vain: all the time there are situations when it is better to push the rear.

When is the best time to use the bike‘s rear brake? The options are:

  • slippery coating;
  • potholes and bumps in the road;
  • puncture of the front wheel of the bicycle;
  • front brake malfunction.

Ukrainian asphalt Potholes and bumps in the road

When riding on dead bad surface, the wheels of your bike are constantly bouncing and hovering in the air. In this case, too, it is better not to use the front brake. When it is clamped at the moment of separation of the front wheel from the soil, it stops. And the subsequent landing on a clamped stationary front wheel can end up sadly.

What Happens to Front Brake Users in Brief

Front brake malfunction

And the last reason to use the rear brake on a bicycle is a banal front brake malfunction. due to a cable break or for another reason.

We cannot but attach a video with a clear example of what sooner or later happens to those who use exclusively the front brake:

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Loose brake cable

How to determine if the problem is in the cable?

2 Reasons Why Your Disc Brakes Don’t Work

If you have a loosened brake cable, then the brake lever is reaching the handlebars, and the pads are not yet firmly pressed against the rim. That is why the wheel does not slow down.

The main thing here is not to overdo it. You can pass the cable and it will break over time.

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. After that. bend in the required direction.

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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. The problem may be the brake lever, dirt can also get into it. Then you will need to disassemble and clean it. A more serious problem 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 place of leakage, you need to replace the gaskets, the worst option is to replace the hydraulic line.

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 move it towards the friction side. 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.

Centering the caliper in relation to the disc

Now for 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 the adapter, and the caliper is already there. However, the bolts should not be tightened just 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.

Disc mechanical brakes

Mechanical disc brakes have the same problems as V-brakes. oil getting on the working surface, tightening the cable, adjusting the pads.

What is the difference between pads on mechanical disc brakes and pads on V-brake?

Unlike V-brake, where 2 pads move, on disc brakes only one pad moves, and the second always stays in place, and the pad that stays in place should be as close as possible to the disc brake.

Otherwise, when braking, you will bend the disc until it rests against the second block. Thus, we immediately have two problems: bad brakes and a bent brake disc.

How to adjust a fixed pad in mechanical disc brakes?

Music used in the video: JK Soul. Battle of life (Gramatik)

We set the levers symmetrically

In order for the left and right pads to wear evenly, they must be at the same distance from the rim. Adjustable by spring tension on the brake levers. To equalize the force that returns the left and right brake levers to their original position, use the adjusting bolts located at the base of the levers.

By twisting the bolt clockwise, we tighten the spring, unscrewing it. we loosen it. By pressing and releasing the brake, we check the uniformity of the removal of the pads from the rim. Tighten the bolts on the left and right sides until the pads move the same distance when the brake lever is released.

Adjusting the brakes (V-Brake)

Setting up the brakes means paying attention to every detail, from the brake levers to the brake pads.

Brake levers should be located so that they can be reached quickly and comfortably. In order to adjust the position of the brake lever, loosen the fastening screw, place the handle as it is convenient for you and fix it. Usually there is a screw on the brake lever, with which you can adjust the distance of the brake lever to the grip. adjust the position of the lever with it.

Second step. Position of the brake pads

It is easier to adjust the position of the brake pads as follows: press one of the pads with your hands close to the rim, adjust its position. Make sure that the block is not too low (the edge of the block is below the rim), but also not too high. the block touches the tire.

I would like to draw special attention to the next moment, since there is little clear written about it. Until the nut of which the shoe is fixed is not tightened, the shoe has three degrees of freedom: the washers form something like a ball joint. (Pay attention to how many washers are there? That’s what they are for!). It is believed that the leading edge of the pads should touch the rim slightly earlier than the rear. Therefore, we do this: put a small gasket under the rear end (see fig).

This number of washers is needed to get something like a ball joint

Now you can tighten the nut that fixes the shoe.

Step three. Centering the positions of the levers

At this step, you need to fix the brake cable: so that the brake pads touch the rims at least a little if you press the brake lever. At the bottom of the levers there are special bolts that adjust the tension of the springs that press the pads against the rim.

We set it up as follows: press the brake and see which of the pads touches earlier. For the one that touched earlier, we increase the spring tension (or vice versa, weaken it on the other side). It is necessary to ensure that the pads touch the rim at the same time.

Fourth step. Adjusting the distance from the pads to the rim

I believe that this distance should be as small as possible. (1-2 mm. If the rim is even). But then the brakes will work very sharply. the slightest pressure leads to sharp braking. Therefore, the distance can be made a little more.

The distance is adjusted in two steps: first, due to the screw with which the cable is attached to the brakes. Then fine tuning on the brake lever.

Instruments

We need a flat head screwdriver (or a small Phillips head) and a 5mm hex wrench.

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. The problem may be the brake lever, dirt can also get into it. Then you will need to disassemble and clean it. A more serious problem 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.

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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 place of leakage, you need to replace the gaskets, the worst option is to replace the hydraulic line.

Mechanical v-brake design

Mechanical. this means that the force is transmitted using a braided cable.

The cable drive is a steel cable with a lug on one end and a tip on the other, sliding inside the jacket with a spiral wound wire. When the handle is pressed, the cable transfers force to the brake lever (s), which causes the pads to press against the braking surface. Such a drive is simple, reliable and maintainable enough. Its disadvantage is the susceptibility to contamination of the cables, which leads to their rusting and, accordingly, deterioration of the brakes up to failure. In addition, dirt and water in shirts can freeze in winter.

Even if dirt is avoided, over time the plastic tubing inside the shirts will rub off and the quality of work will decline. Therefore, cables and shirts are recommended to be changed during seasonal maintenance. In this case, lubrication of the cables is not required, since temporarily improving the work, it contributes to further contamination and freezing of the shirts in the future.

  • Cable tension;
  • Brake Lever Lever (Some Models).
  • Simplicity and low cost of construction;
  • Ease of field repair.
  • The need for regular adjustments as the pads wear out and the cable stretches;
  • Sensitive to contamination, freezing and rusting of the cable drive.

With such brakes, the braking force is transmitted to the wheel rim by means of 2 pads pressed against the rim by levers, which, in turn, are driven by the muscular force of the biker through a cable drive or hydraulically.

There are currently four types of rim brakes used on bicycles:

  • Cantilevers. on aging bikes and cyclocross bikes.
  • Caliper brakes. on road and some road bikes.
  • V-brake (vibrake). on other bicycles.
  • U-brake. on BMX.

In general, the above division practically leaves no room for maneuver. nothing can be put on a road bike except caliper brakes, vibrakes cannot be replaced with cantilevers (not counting very old cantilevers) and tick-borne ones, and cantilevers can only be replaced with rare mini-vibracks.

There are 2 types of pads used in rim brakes: regular and cartridge. The difference is that the cartridge block can be disassembled into its component parts and when worn out, you do not need to buy the whole block, it is enough to replace the lining.

How to Adjust Your Bike Brakes the Easy Way

There are vibrating racks with parallel pad supply. they use a parallelogram mechanism, which improves the performance of brakes with worn pads, but is susceptible to clogging and wear of the hinges.

It is believed that the best V-brakes are produced by Avid (SD5, SD7 and beyond) and previously produced by Shimano (Deore XT, XTR, currently only in the tourist subgroup of the Deore XT group).

  • Ease of construction, maintenance and repair.
  • Unification of design: levers, brakes and pads of different companies are compatible with each other.
  • Ease of combining with the trunk.
  • Cheap Pads.
  • Light weight.
  • Good vibrakes have high power.
  • Low price.
    • Possible exposure to contamination and icing of the mechanism;
    • Braking on budget models is worse when the rims are wet and dirty;
    • Lack of braking on icy rims;
    • Sensitive to figure eights on rims;
    • Relatively fast pads wear on budget models;
    • Rim wear;
    • The need for adjustment.

    The combination of advantages and disadvantages determines the area of ​​use of rim brakes:

    Note that when buying a bike below the average level (up to 700), it is absolutely not necessary to overpay for disc brakes, since in this price range they will not work much better than vibration racks, but they will noticeably increase the weight and cost of the bike.

    Customization

    The principle of operation of rim brakes is clear, I think to everyone. 2 brake pads located opposite each other parallel to the wheel, between them there is a rim. When you press the brake lever, the pads compress the rim, stopping the wheel. The mechanism is driven by a cable pull.

    In order for the brakes to work without failures, you need to monitor the integrity of the cable. If its braid is loose somewhere or at least one fiber breaks, the cable should be replaced. It is important that the cable runs freely in the shirt. And make sure that you do not have.

    The basis for good brake performance is the correct pressure of the brake pads against the wheel rim. It is regulated by the pad fasteners, which consists of a set of aluminum spacers and a nut on the axle. This kit allows you to fix the last at the desired angle. And to do this, you need to loosen the nut on each pad and firmly clamp the brake. Position the pads so that they are horizontal, touching the rim with their entire surface, but not touching the tire (see picture). And carefully shade the nuts without knocking out the position of the pads. This is true for cartridge pads. For ordinary pads, you need to press the rear of the pads horizontally to the rim first (see below)

    If when you press the brakes one lever moves weakly, then the screw on this lever should be tightened a little, too easy. unscrew.

    When set up correctly, v-brakes will perform just as well, and some models even better than disc brakes! The design features of the v-brakes allow adjusting the pads in almost any plane, but this is not possible with caliper rim brakes. The price of rim brakes is significantly less than that of disc brakes, they weigh less and are easier to adjust than disc brakes.

    The pads should be replaced with new ones when their braking surface is erased to the level of the grooves for the drain of dirt, that is, when the working surface becomes completely flat. And if the pads are worn off only on one side, this means that they were installed incorrectly, and they will also need to be replaced.

    First, loosen the screw holding the cable.

    The main thing when installing a conventional brake shoe is to put on in the correct sequence all the washers and gaskets that make up their fasteners. Also note that some models of pads can be divided into left and right, this is indicated on the pads themselves, take this into account when installing.

    Replacing cartridge pads is even easier. They have a metal base and only the rubber pad needs to be replaced. On these pads there is a locking pin (do not lose it), you need to pull it out and slide out the rubber pad. Then insert new pads and secure with a cotter pin. When installing the trims, pay attention to the indicators for the right and left side.

    After replacing the pads, screw the adjusting drum on the brake lever fully and unscrew it one turn. Squeeze the brake levers with your fingers, reinstall the cable and secure with the screw. The distance from the wheel rim to the shoes should be 2 mm.

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    Rim brakes have a very simple principle of operation. two brake pads installed opposite each other and parallel to the wheel, with a rim between them. Pressing the brake lever force through a system of cables and shirts. transmitted to the brake levers, which press the pads against the wheel rim, stopping it.

    For smooth operation of the rim brakes, you need to monitor the integrity of the cable and the absence of eights on the wheel. If at least one fiber breaks on the cable, it must be replaced. The cable should move freely in the shirt and if it gets stuck it is necessary to change either the cable or the shirt.

    The main thing in the high-quality operation of rim brakes is the high-quality pressing of the pads to the rim. This can be adjusted by fastening the pads. The fastener consists of a set of washers, gaskets and a nut, it allows you to fix the shoe at the desired angle.

    To adjust, loosen the nut on each shoe slightly so that the shoe can be moved with your fingers, but it will not move. Place the block parallel to the wheel rim, note that it must not touch the tire (the distance between the block and the tire must be at least 1 mm.).

    • If you have soft rubber brake pads, they will deform when braking. Therefore, they must be installed so that the leading edge of these pads is 1 mm. closer to the rim than the rear. For this, a 1-1.5 mm thick gasket must be placed under the rear parts of the pads before adjusting. For example, a piece of rubber cut from a worn bicycle tube.
    • If you have brake pads with a rigid base that do not deform when braking, you must install strictly parallel to the rim.

    Then look at the brake levers. Squeeze and release the brake levers several times, the levers should converge and diverge equally. This can be adjusted with the spring tension screws located at the base of the lever. We turn the adjusting screw on the lever that deflects too little, and unscrew it if the lever deflects too much.

    In order to remove the wheel, you do not need to unscrew the brake cable, you just need to release it from the clamp. To do this, squeeze the brake levers with your hands and remove the rigid part of the cable jacket from the slot.

    How to self-adjust your brakes to improve performance.

    Adjustment is most often required when the brake pads are noticeably worn or after replacing them with new ones.

    This procedure is not complicated and everyone can do it.

    Adjustment tips

    Correct adjustment and adjustment of the brakes is an important condition for the effective functioning of the system.

    Based on the specific features of the rim kits, there are a number of conditions, the observance of which will help to achieve an optimal result during the adjustment process:

    • the rim, if possible, should not have deformations and damage;
    • the wheel must be dry, free from dirt and sand;
    • adjustment is carried out with a set of keys, hexagons and screwdrivers, sizes and calibers suitable for this purpose;
    • adjustment is carried out in accordance with the provided algorithm, and only undamaged system elements, with permissible production rates.

    For vector mechanisms, such an algorithm includes the following actions:

    • Checking the vertical position of the brake pads relative to the wheel rim. The center axis of the brake surface of the pad must be centered on the brake track of the wheel rim. The shoe moves up and down in the corresponding grooves in the brake lever. Fixed in the desired position with elongated nuts.
    • Often, as a result of emergency braking, clogging of the inter-pad space with dirt, weakening of fixation, a slight rotation of the pad about its axis occurs. The result can be rubbing of the pads on the tire. The elimination of such problems is carried out in a similar way. The fixing nut is unscrewed, the block is set to its original position, the nut is clamped.
    • During operation, the pads wear out, the gap between the brake surfaces increases, and the braking efficiency decreases. The clearance is adjusted by changing the tension of the metal cable. To carry out this operation, it is required to loosen the cable fastening bolt located in the upper part of the brake lever, by pulling the cable a gap is set, approximately 1 mm, the fixing bolt is clamped. To facilitate the task, an object of a specified thickness (for example, 2-3 layers of thick cardboard), placed between the brake surfaces, will help. After tensioning the rope and removing the cardboard, the set gap is retained.
    • We achieve symmetry of the clearances of the pads relative to the brake tracks. For this purpose, the ability to adjust the force of the return springs of the brake levers is used. In the places where the springs are attached to the levers, there are adjusting screws, the rotation of which leads to a weakening or strengthening of the spring’s resistance. When the adjusting screw is tightened, the spring is tensioned, the lever deflects from the wheel surface, and the gap increases. When the screw is unscrewed, the reverse processes occur, that is, the lever moves towards the wheel, the gap decreases. The engaged levers move synchronously with this adjustment. Moving the left arm toward the rim increases the clearance on the right side, and vice versa.

    Correctly performed adjustment operations result in a flawlessly functioning braking system. The following criteria are used to check the quality of the adjustment:

    • the pads are located parallel to the brake tracks of the rim;
    • the distance between the working braking surfaces varies within 1-1.5 mm;
    • visually, the pads are fixed symmetrically in relation to each other;
    • the adhesion of the braking surfaces occurs synchronously on each side of the rim.

    After completing the above measures, a mandatory performance check follows. Initially, it is carried out at idle speed. To do this, the front wheel is lifted off the surface and spins up. The control handle is clamped sharply. When set correctly, the wheel stops immediately. The rear wheel is checked in the same way. The next step is to test it in action. The bike accelerates over a short distance of 5-10 m, the brake lever is squeezed out sharply. If the bike stops halfway through the lever travel, the system has been serviced correctly, if not, the cause must be investigated and rectified.

    Disadvantages of disc brakes:

    Due to the complexity of the design and the constant introduction of structural changes by manufacturers, it may be difficult to repair and replace individual components. 2. The disc is easily deformed and virtually irreparable. Therefore, if the bicycle falls and the disc hits, or, say, during careless transportation, the disc brake may become unusable. 3. The load on the spokes and on the hub increases. 4. It is inadmissible to get on the disc of oil and other lubricants. 5. The mass of disc brakes is greater than that of v-brakes. 6. Comparatively higher cost.

    The choice is yours, friends! May the force be with you 🙂 Watch the video for a complete picture of bicycle brakes:

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