Check the condition of the cables and shirts
This item is intended solely for mechanics. Before adjusting the mechanical disc brakes on a bicycle, carefully check the condition of the cables and shirts.
If the cable is damaged, namely, if it is fluffed, broken individual fibers are observed, then it should be replaced without fail. It doesn’t matter if the cable changes or not, it must be lubricated before adjusting the brake.
Mountain Bike Maintenance : Why Do My Mountain Bike‘s Rear Brakes Not Work Well?
We also inspect the cable jacket. If cracks or tears are visible on it, then it is better to replace it.
Benefits of disc brakes
- Disc brakes are less clogged when driving, as they are located closer to the center of the wheel, they work in mud, on snow.
- Allows you to more smoothly regulate the braking force than rim. In other words, they have better modulation.
- Provides more powerful braking than V-brakes.
- Can be used with slightly curved wheel geometry, eights do not affect brake performance.
- Disc brakes rarely require service.
- Do not wear out the rim.
- Allows the use of wide tires.
- Long pad life.
- Bent rotor alignment is easier on them than on hydraulic disc brakes.
- Can be used in harsh environments.
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:
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 overdo it, just remove a thin layer.
After you have completed this procedure, try not to touch the pads and rotor with your hands or oily objects.
Learn to feel the brakes
On steep descents, braking is a kind of art to find the edge of wheel locking, both rear and front, and the worse the grip, the more important it is.
It is unlikely that any recommendations can be given here, except for the development of reflexes and the acquisition of flair.
But for example, I can advise such a technique when braking backwards on a descent. try to brake impulsively: quickly squeeze all the way and release the handle, this will allow you to determine the blocking edge by wheel micro drifts, in the process you will understand with what effort you need to press the brake so as not to block the wheel but constantly be on the edge.
With the front brake, in principle, you can also train in a similar way, but it is better not to approach the wheel blocking itself, but to stop in the effort on the handle when the deceleration has become quite intense.
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 an 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 turn 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.
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 resemble pliers.
This brake is as simple as the bike itself: roughly speaking, these are two levers each with rubber pads, attached to the stays of the fork and the rear triangle, converging under the action of a cable, which in turn is selected by a handle on the handlebar.
The system is as simple as it is effective. Such a mechanism practically cannot break and can be easily adjusted. There are several types of rim brakes:
Checking the condition of the brakes
First of all, “unfasten” the brake, as shown in the photo.
Check how the cable (G) moves in the shirt (A) by pressing and releasing the brake lever and pulling the cable back with your finger. the movement should be free, without delay. If the cable pulls hard, it may be damaged, the shirt or cable guide (C), or dirt has accumulated inside the jacket or cable guide. They must be removed and cleaned or replaced.
Check the condition of the pads (J). They should show dirt drainage grooves (the block should not be smooth). Worn pads without grooves must be replaced. Check that the pads are complete with washers and that they are correctly installed.
Observe the order of the washers when installing new pads.
The brake levers (I) must rotate freely in their seats and spring apart after being compressed. If the movement is difficult, the brake during operation may get stuck in the closed position and rub the pad on the rim. In this case, you can remove the levers from the seats, clean and lubricate the contact points and reinstall.
When installing, make sure that the protruding pin on the arm fits into the hole in the frame, and that the hole on the left and right arm is the same.
Scheme of work
The principle of operation of the system is based on the use of the friction force arising in the process of interaction of brake pads and wheel rim.
Structurally, any rim system includes:
- paired levers for the front and rear wheels;
- brake pads made of dense rubber;
- control handles;
- cables connecting all components;
- brake cable covers.
The scheme of the kit is quite simple. When physically acting on the control handle, the force is transmitted through the cables to the levers with pads fixed on them. There is a clamping of the wheel rim between the surfaces of the shoes. As a result, the bike slows down or stops. The more the application force, the more the rim is clamped, the faster the object slows down.
Compared to other types of rim braking mechanisms, they have a lot of advantages: they are not expensive, easy to maintain and repair, have a high degree of modulation, and practically do not have a harmful effect on the hubs and spokes of the wheel.
At the same time, this design has a number of significant disadvantages, which are recommended to be taken into account when choosing and purchasing a bike.
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.
“They are easy to use, cheap and easy to replace. But, unfortunately, everything cheap has its drawbacks. The rim brake is not a priority in its class. This is due to its design. The pads often do not clamp the moving part as it should, so the braking distance becomes quite large. But expensive mechanical brakes can be quite competitive. In general, adjusting V-brakes on a bicycle does not require much effort, special techniques, so this class is suitable for beginners and amateurs.
No Rear Brake = No Riding!
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.
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.
Types and characteristics
Rim brakes have come a long way during their evolution. They have come down to us in the form of pliers, cantilever, V-brakes and hydraulic systems. Each type has its own specific features, advantages and disadvantages.
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Reading → Brake front and rear
by popular demand. a post about braking. my practical knowledge in this matter is limited to a single trip with an emergency at the end, but since there were guys behind them with flashing lights, from the abundance of adrenaline in my blood, I did not remember anything. I did everything on the machine, I just remember that the rear wheel was blown by half a meter, I squeezed it all the same.
In theory, when you press the brake, the caliper presses on the wheel, the wheel wants to stop while everything is simple. But if you squeeze the brake, demolition begins, which is bad. Strong pressure is not necessary, but weak is also not good. you need to act on the edge (probably everyone has heard about this)
further. when braking, the weight distribution changes, the fork is loaded more, the downforce increases. therefore, the friction force increases, the braking distance is shortened. With this, too, everything is clear, we cannot influence this. it all happens when the front brake is pressed by itself.
Now comes the fun part. the rear brake! it turns out not only knows how to slow down. We put on the brake, and our whole bike gains moment of rotation around the axis of the rear wheel. for clarity: thanks to this, we can load the fork even more and, since the grip has increased, it is possible to clamp the front brake more tightly without the risk of breaking into a skid. I don’t know how the locked rear wheel behaves, but most likely it will provide the same torque, but it will slow down itself.
How the stoppy affects the braking distance is difficult to say, it seems that the fork is loaded to the very least, but at the same time, you can’t press the brake hard (it’s understandable why) I read somewhere that stopping braking is less effective
for the completeness of the post, Комментарии и мнения владельцев from experienced bearded bikers are required. And everyone else will also be useful)) special thanks to Denis Grachev for the visual aid, though taken without his permission 🙂 I hope he will not be offended, the photo is super))