The bike should be matched to the child’s height. He should reach the pedals with his feet. The seat should be comfortable, soft
You also need to pay attention to the material from which the wheels are made. In children’s bicycles, wheels can be made of PVC or rubber
Consider the advantages and disadvantages of the former. So, PVC wheels are light in weight, they are NOT sensitive to punctures, so they do not need to be pumped up. At a cost, they are cheaper than rubber, less flexible, so the unevenness of the road surface is smoothed less. They are prone to slipping, since their coefficient of adhesion is slightly lower than in rubber models. Although it is not a hindrance if the child chooses a quiet ride at low speeds. Usually these tires are recommended for beginners. They are safe, the wheel is almost NOT possible to damage (except if a dog bites it). If it was damaged, then in this case you will have to completely replace the entire wheel.
Side wheels for children’s bicycles. Inflatable rubber wheels
- You can adjust the height of the bike: if it lets the air out of the slope a little, you can lower the height of the wheels by 1 cm.
- Nice appearance. You can select tires in different thicknesses and heights to give your bike a cool look. Some wheels have reflective stripes on the side to improve the child‘s visibility and safety in the evening;
- Have good tread.
Rubber inflatable tires also have disadvantages. they can be easily punctured. Therefore, you need to make sure that the child does not travel in those places where you can stumble on broken glass or nails. But if, nevertheless, the trouble happened, then only the tire can be replaced, and not the entire wheel. Rubber tires are recommended for active kids who like to ride down hills, on grass, sand, uneven road. Thanks to their good tread, riding them is not only safe, but also comfortable.
What to look for when choosing side wheels for a children’s bike
Several factors to consider when purchasing casters:
- The presence of metal brackets. Some manufacturers use cheap alloys to lower the cost of production. Therefore, it is recommended to check the strength of the brackets before purchasing and try to bend them with your hands.
- Wheels are often equipped with inflatable chambers. But they can be damaged during the trip and will have to be replaced. It is better to buy wheels with plastic or dense rubber tires, they will last much longer.
- Be sure to consider the number of speeds on the bike. The selection of suitable components depends on this.
- Fix the elements securely. Check the strength of the bindings, otherwise the child may simply lose the safety wheels during the trip.
Features and classification of bicycles
Modern manufacturers offer bicycles for different age groups (see here). So, for the smallest (1-3 years old), they have developed scooter bicycles, models with pedals on the front wheel and a comfortable handle for parents, tricycles. For children 3-4 years old, models with rubber wheels and side training wheels are designed. They are equipped with a strong and soft seat, have chain guards and guards on the handlebars, one speed. Wheels are 12 inches. For children 4-6 years old, it is worth choosing bikes similar to previous models, only with 16-inch wheels. These bicycles can still be equipped with a rear foot brake.
Bicycles for children 6-9 years old are equipped with a large number of speeds (up to 6), wheels of 20 inches, and also have rear and front brakes or front shock absorbers. Bicycles for children 9-13 years old are NOT inferior to adult models. The wheelbase is 24 inches, there is a front shock absorber, up to 24 speeds, rear and front brakes. In order not to be mistaken with the choice, here is a table of correspondence between the size of the wheels and the age of the child.
DISADVANTAGES OF DISC BRAKES:
- All disc brakes are High Price;
- There is a load on the spokes and bushing;
- A special tool is required to service the hydraulics;
- Their weight is quite heavy;
- Often interfered with when installing the trunk.
An important issue when installing disc brakes will be the choice of the rotor size. It can be of various sizes. from 140 to 220 mm. Rotor size for brake efficiency (the larger, the more efficient).
If you are NOT going to use your bike for extreme riding, then you can safely take a rotor in sizes 160 and 180 mm. If you need a more powerful brake, then the rotor sizes 203 and 220 mm are suitable for you.
Let’s talk about brake pads. They differ in their content (metallic or organic). As a filler in metal pads, metal sawdust is used, which provides them with greater wear resistance, they rub for a long time.
Organic pads are softer, smoother when braking, lapping is quick, as a result of which they have better braking.
HOW DOES DISC BRAKE INSTALLATION?
- It is necessary to attach the brake levers to the steering wheel, then adjust their position using a hexagon.
- Then install the caliper in the special disc mounts on the frame.
- Now it is necessary to install the brake discs using the bolts, which are included in the kit, on the hub.
- Take the cable, fix it in the brake lever, insert it into the shirt. There are guides on the frame. use these to guide the shirt to the caliper.
- The last step is to secure the cable and adjust the brake.
WHAT ARE THE TYPES OF DISC BRAKES:
- Hydraulic brakes: have a control cylinder with a piston in the device, which is located in the brake lever on the steering wheel. The brake pads are actuated by this piston. A special high-strength sleeve is used to connect the pads. The hydraulic brake system is sealed and filled with liquid (oil).
- Mechanical disc brakes in their design have a cable that pulls the drive lever, as a result of which a simple mechanism is used, which simply presses the pads against the disc. The role of a simple mechanism can be a multi-threaded lead screw, cam or wedge. The movement of the cable and shoes occurs in planes, which are perpendicular to each other.
- Hybrid disc brakes (as the name implies) have both hydraulics and mechanics in their design. There is also a cable, which, using a lever, activates the hydraulic part (its location is completely in the brake body and consists of two cylinders, there is a small amount of oil between them).
Of course, such brakes have their disadvantages and advantages.
Bicycle disc brakes: HOW TO CHOOSE AND INSTALL THEIR CORRECTLY
When choosing a bike, a very common question is the choice of the brake. Since there are several types of them (rim, pedal, disc, etc.), a problem arises: “What brakes to choose for a bike?” In the article we will talk about the advantages and disadvantages of disc brakes on a bicycle, how to choose and install them correctly.
Disc brakes on a bicycle: HOW TO CHOOSE AND INSTALL ON a bicycle
The most relevant braking system at the moment is disc brakes on a bicycle. How to choose and install them for which bikes are suitable, the advantages and disadvantages of such a braking system, we will talk about this now.
The disc braking system is quite simple in design. A steel disc is taken, which is fixed next to the spokes on the wheel hub on the left. Then the pads on the left are pressed against this disc, and the braking force will be the greater, the more they are pressed.
WHAT ARE THE ADVANTAGES OF DISC BRAKES:
- These brakes are by far the best for mountain bikes (they are almost useless for leisurely city walks)
- They are not afraid of the dirt that flies from the wheels, and you can also vouch for their reliability in any weather and temperature;
- These brakes are NOT prone to eights and do not wear on the wheel rim;
- The hydraulic brake does not require adjustment and also has a fairly long service life;
- No heating of the rim when you brake on a long downhill.
WHAT CAN YOU SAY ABOUT DISC BRAKE MAINTENANCE?
For effective braking, you must monitor its condition completely:
- Check the tension of the cable regularly. its operation should be clear and smooth.
- Also check the condition of the pads. To do this, they need to be removed periodically.
- Also inspect the rotor and clean it from plaque (it is best to do this with sandpaper).
Squeaking brakes are the most common problem with disc brakes. Of course, you can use the services of a specialist in a bicycle workshop, but do not rush, as there are the most common reasons for this squeak, which do NOT require a trip to a specialist to find out.
- The first prerequisite may be low-quality and cheap material, which was used in the manufacture of the last. In this case, you should purchase new branded pads to avoid damaging the rotor surface. You should also consider the incompatibility of the pads with your brakes.
- A squeak can also be heard if the pads are still new (there is a certain layer on the surfaces of the pads, which causes a squeak). Ride for a few days, and if the creak does NOT disappear, then the reason is different.
- Also, a squeak is emitted when the pads are worn out and the rotor comes into contact with the plate.
To summarize all of the above, we can conclude that disc brakes have practical value when driving more aggressively. During ordinary city cycling, their practical value is zero, since they are not fully used, and there is no point in purchasing expensive disc brakes.
However, if you do decide to purchase such brakes, then it is better to buy mechanical brakes, as they are the golden mean for many cyclists.
Of course, if you need high braking power, then you won’t find better hydraulic brakes. Such brakes are used in extreme types of cycling (for example, downhill). Of course, they are much more expensive, but it’s worth it.
Now you know everything you need to know about disc brakes, so you can safely go shopping.
We set the levers symmetrically
For the left and right shoes to wear evenly, they must be at the same distance from the rim. The tension of the springs on the brake levers is adjusted. To equalize the force that returns the left and right brake levers to their original position, we use the adjusting bolts located at the base of the levers.
Twisting the bolt clockwise we tighten the spring, unscrewing it loosens it. 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 will not move the same distance with the brake lever released.
Adjust the position of the pads
“Fasten” the brake by squeezing the levers and placing the cable guide (C) in the stop (D). Loosens shoe retaining bolt (K) with a hexagon. Presses the lever with the block to the rim and set the block so that it:
- Adhered to the rim with the entire surface
- Did NOT touch the tire
- Placed parallel to the rim
In this position, the block must be fixed by tightening the bolt. If the bolt is heavy, the block can move, and it needs to be corrected. It will be easier if you find an assistant who will grip and hold the brake lever while you tighten the bolt.
If your brakes squeal, try the following.
Before tightening the bolt, place a folded sheet of paper under the rear (in the direction of travel) of the shoe, then tighten the bolt. So the pads will be smoother to press against the rim when braking (first by the front, then by the rear) and will NOT “creak”.
Do the same with the second block.
How to assemble a handbrake on a kid’s bike
Road bike modern type with 28 wheels “you need front caliper brakes with a distance of 80 mm from the axis of attachment to the pads. Here are two proven caliper brakes with a distance of up to 90mm. Both brakes showed full suitability and good quality for me.
Option 1. Caliper brake on one axle (like the Salyut bike):
My weight is 85, from my cruising speed of 17 km / h with emergency braking with one front brake on horizontal asphalt it brakes quite effectively, braking distance of three meters to a full stop.
Any special deflections or ticks during braking were NOT noticed (thick enough aluminum)
Out of the box, the pliers were not always retracted into the opposite position symmetrically, the right one sometimes remained with the rim touching. I blew the hinge with aerosol graphite grease, squeezed it. Now it seems normal. I had to slightly lower the front wing (within the limits of the norm), the right “tick” touched the wing when the brake was pressed and moved it.
For a walking led, a brake is quite suitable. The only drawback is that the pincer levers move slightly up and down in the wing area during operation and the maximum wing raised interferes with the brake operation. Not a problem for standard tires, but when installing 28×2.00 tires it is better to raise the fender as high as possible.
Subsequently, I rearranged this one-axle brake on my daughter’s bike (wheels 16 “) installed fine.
Option 2. Caliper brake on two axles (similar to the HVZ bike):
In uniaxial brakes, the pincers moved slightly downward to the wing during operation, and the wing had to be slightly lowered. In biaxial pincers, all moving parts from the wing side move only to the sides, so the wing can be raised as much as possible. This is important for me, because I have 28×2.00 tires instead of stock 28×1.75. there is not enough space.
The new two-axle brakes have short pads, it seems that at minimum speeds they work harder than the previous single-axle brakes, and on the contrary, they brake less intensively at high speeds. But most likely the whole thing is in the pads, on the new ones they are Not only shorter, but also to the touch a little more “plastic”.
The biaxial ones have a simple clamp synchronization mechanism, which is good. Here the biaxial fork mounts are several mm longer, which is also good. In terms of quality, both the old single-axle and the new two-axle ones are comparable. service brakes work normally even on small hills.
(In the photo, the wasps of the mites are smeared with graphite grease to protect against dust)
Checking the condition of the brakes
First of all, we “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 inside the jacket or cable guide of accumulated dirt. They must be removed and cleaned or replaced.
Check the condition of the pads (J). They must show grooves for the drain of dirt (pads must 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 washers when installing new pads.
Brake levers (I) Should pivot freely in their seats and spring apart after compression. If the movement is difficult, the brake during operation may get stuck in the closed position and rub with the shoe 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 lever is in the hole on the frame, and that the hole on the left and right of the lever is the same.
Unpacking and Installing Basic Bicycle Parts
This is what the bike box looks like when it comes from the factory. All bikes usually have a crankset, chain, rear and front derailleurs, rear wheel, brakes and steering column already installed.
Separately packed steering wheel, seat, front wheel, pedals, reflectors and other small things.
A number of tools are required to assemble the setup:
- Hexagons (4, 5, 6 mm), or better a set,
- 15 wrench (for tightening the pedals),
- Key for 10,
- Phillips screwdriver,
- Pliers (for crimping the cable),
- Wire cutters (for cutting the cable).
We take the bike out of the box. Cut off all plastic clamps with pliers or powerful scissors and remove the packaging. Be careful. it is easy to damage the paintwork of the frame at this stage.
The bike is ready for assembly.
First attach the saddle to the seatpost. To do this, use a 6mm hexagon to unscrew the mount on the seatpost, install it in the grooves of the saddle frame, close it with a bracket on top and tighten it. This clever design also allows for back-and-forth movement and tilt adjustment. Now it will be enough to simply tighten the bolt, and it will be more convenient to make the settings on the assembled bike.
Attaching the reflector as close as possible to the saddle.
We lower the entire structure into the seat tube to the end and securing with an eccentric clamp. If it closes too easily, then open it to the end, turn the tightening wheel and try to close it again. If it does not close, on the contrary, it weakens.
Next, we are engaged in the removal of the steering wheel and the steering wheel. On different bicycles it happens differently: either the stem is already attached to the handlebars, or it is available. In any case, the stem is set first. When installing the stem and handlebars, pay attention to the derailleur and brake cables. they must NOT be tangled. Pay attention to the vertical marks on the stem. this is the maximum possible lift.
There is an important bolt hidden under this little plug! Using a 5 or 6 hexagon, the stem is fixed in the steering column, and the steering wheel is height adjustable.
Let’s take a wheel in front of him. First you need to correctly install the eccentric (it is in a box with small things). The photo shows the correct position of all parts. Pay attention to the springs. they are located with a narrow part inward, i.e. To the wheel.
Remove the plug and the spring from one side of the eccentric (from the one where there is no lever) and insert it into the front wheel hub. The question may arise, which side to insert it? Just look at which side it is mounted on the rear wheel (usually on the left) and follow the analogy.
Next, insert the wheel into the fork. It is necessary to “unfasten” the front brake of the bicycle in advance (in the case of rim brakes) or remove the rubber band from it (usually in the original packaging it is fixed with an elastic band or a tie).
The easiest way to tighten the cam is by approaching the bike from the front. In this case, you can track whether the wheel is centered. Tightening is done as follows: turning the wheel clockwise to the left and trying to close the lever. If it closes very easily, fold it back and turn the wheel again, until the eccentric does NOT forcefully close. It is not necessary to overdo it, otherwise you can break the eccentric!
Now you can pump up the wheels. The recommended pressure is always indicated on the tire in psi and bar. Bar = atmosphere. Please note: the pressure in the bicycle wheels must be 3 atmospheres or more. 3.5 is the best option. 2.2 as in cars is NOT good anywhere. During operation, periodically check the pressure in the wheels. this is a guarantee of the absence of “eights”.
Install the pedals. The photo shows that each pedal is labeled as L or R. Sometimes stickers are also molded. L (Left). left, R (Right). right. Be careful: pedals have different threads! Both pedals twist “in motion” of the bike, ie. Left to left (counterclockwise) and right to right (clockwise).
First, we twist them with our hands, and then we tighten them with a key by 15.
If the chain is not in place, it can easily be returned there. To do this, press on the rear derailleur foot and the chain looses. Now you can simply grab it with your hand and put it on one of the chainrings.
Installation and adjustment of the front brake; adjustment of both brakes
Now let’s start installing the front brake. Find a curved tube like this in the box. It is necessary to thread the front brake cable into it so that the wide part is at the top, and the narrow tip at the bottom is closer to the brake lever (on the next photo).
We do it as in the photo. The elastic must be worn to how you will fasten the cable. An elastic band is needed to protect the cable from dirt.
Now loosen the bolt and put the cable there.
We squeeze the levers so that 2-3 mm remain from the pads to the rim. And we tighten the bolt (without fanaticism, otherwise the cable will start to “push”).
We leave a small part of the cable (5-7 cm.), Cutting the rest with nippers (nippers are needed very good, otherwise the cable will fluff at the end). Next, we put on the tip and clamp it with pliers. If you have the right tools on hand, do this step later. But without putting it off for a long time. the cable may “fluff” and you will have to change it.
Further, the cable can be wound by the lever so that it does not dangle.
Now you need to adjust the brakes. It would be good to devote a separate article to such a difficult question, but now I will try to briefly describe the adjustment process.
The precise operation of the brakes consists of many nuances. First, spin the wheel (previously inflated to the recommended pressure). is there a figure eight? If so, then it needs to be fixed. It is better to do this with an experienced master or look for an article on eliminating eights on the Internet. If everything is in order, we work further.
When assembled, the brake pads must be equidistant from the rim. This is achieved by the tension of the cable. you can loosen the bolt with which you fastened the cable and tighten it more. And then there is the “lamb”. it is right next to the brake lever. they can also tighten or loosen the cable. Never screw it out completely! The pads themselves must be parallel to the rim. Check if this is so. If not, you need to loosen the bolt securing them and adjust their position (see photo). You can, for example, clamp the brake (then the pads will press parallel to the rim) and immediately tighten the bolts.
Now we press on the brake lever and see how the brake levers come together. And they must converge at the same time! Look at.
If, when you press the brake lever, one lever presses the shoe faster than the other, you need to make the adjustment with special screws (see photo). The adjustment is made as follows: choose the lever where the block is pressed faster and stronger against the rim and the screw from this side is tightened clockwise by one or half a turn. Click and see if the situation changes. Usually, the pads begin to press against the rim at the same time after adjustment with one screw. If there is, then the screw on the other levers (where the block is farther from the rim) turn counterclockwise by one. half a turn. Continue the described actions, until the result is ripe, as on. The same procedure must be done with the rear brake.
Adjusting the position of the brake lever and the tension of the cable
To bring the brake lever closer to the steering wheel (for example, so that you don’t have to stretch your fingers too much), tighten the bolt on the brake lever.
At the same time, given that the handle is too close to the steering wheel, it is not worth it. It should not touch the grip when fully clamped.
When the position of the brake lever is set, it remains to adjust the cable tension. The task is to bring the pads as close to the rim as possible, leaving a distance of 2-3 millimeters between the pad and the rim.
To do this, you can tighten the cable in two ways:
- For a rough adjustment, if the cable is very weakly tensioned and the pads are far from the rim: loosens the bolt fixing the cable to the brake lever, tighten the cable, tighten the bolt.
While loosening the bolt, hold the lever and cable so that the cable does not “ran away”, And I didn’t have to refuel it in the Landing place.
- For fine tuning, we use the adjusting screw at the point where the shirt comes out with a cable from the brake lever.
To let the screw turn freely, loosen the lock nut by unscrewing it counterclockwise. Turning the screw clockwise, we release the cable tension (the pads move away from the rim), unscrewing it counterclockwise. increasing the tension (the pads are closer to the rim). When the pads are in the desired position, tighten the lock nut.
That’s all! Checking how everything works. If necessary, re-adjust the springs of the levers (item 3).
Setting up the brakes means paying attention to every detail, from the brake levers to the brake pads.
First step. Adjusting the brake levers
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.
Step two. 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 not too high. the block touches the tires.
On the next moment I want to pay special attention, 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 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 nuts that fix the block.
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. There are special bolts at the bottom of the levers, which adjust the tension of the springs, which press the pads against the rim.
We set it up as follows: press the brake and see which of the pads touches earlier. In the one that touched before. increasing 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, which attaches the cable to the brakes. Then fine tuning on the brake lever.
The large washer acts as a lock: when it is tightened, the cable tension adjustment screw cannot be returned.
Brake pads on a bicycle, WHAT ARE
Cycling safety, the efficiency of its braking system directly depends on the used brake pads. Consider what are the brake pads for a bicycle, their advantages and disadvantages.
Depending on the design and price range, the pads are divided into varieties. And first of all, for the two main types of brakes: rim (V-brake) and disc.
PADS FOR DISC BRAKE SYSTEMS
On the market, brake pads for disc brakes Available in metallized (Sintered) and organic (Resin). And these types have both advantages and disadvantages.
Factors such as rider weight, weather and trail conditions, riding style, and rotor size can determine the selection of the appropriate pad composition.
HOW TO INSTALL disc brakes on your bike, AND HOW TO ADJUST THEM?
The most important element of any bike is the brakes. Human life and health largely depend on them. In this article, we will talk about what types of brake pads (types) are, how to install disc brakes on a bicycle and adjust them. adjust.
Metallized Brake Pads
Consist of an alloy of metal-containing substances.
- More resistant to frictional heat than organic brake pads
- Work more efficiently in wet conditions;
- I have a greater resource.
- Make noise;
- Long-term lapping;
- The modulation is worse;
- The caliper heats up instead of dissipating heat through the rotor.
These pads are preferable for riders with a lot of weight. Suitable for use on wet roads in mud and rain. During long descents, they retain their power, although modulation is worse with them.
They work noisily, but due to the greater rigidity of the composition, they have a tangible advantage in resource. After we proceed to the choice of brake pads, first of all, Considering the conditions under which you will use them.
How to set up disc brakes on a bicycle: INSTRUCTIONS
Setting up disc brakes on bicycles is not a complicated process. Now see for yourself. Let’s figure out how to set up disc brakes on your bike yourself, rather than Seeking professional help:
- After fixing the wheel, the caliper should be centered in relation to the rotor by picking up and installing between the mount on the frame and the caliper washers of various thicknesses that are included.
- The position of the caliper will vary depending on how tight the bolts are. Accordingly, the thickness and number of washers will need to be selected to a fraction of a millimeter.
- In the case when the rotor is in contact with both pads and friction occurs, the pads must be diluted. To do this, slightly Unscrew the special hexagon of the caliper, while the brakes will start to work later.
- If you want to achieve a shorter brake lever travel, the hexagon must be screwed in. It may be because of an uneven brake disc, which will have to be aligned.
- During the robot, do not turn the bike over to avoid air entering the system. Also, do not press the handle if there is oil in the system, and the rotor does not stand between the brake pads, otherwise they will shrink, after which you will have to remove the caliper and release the brake pads with a screwdriver.
- When all operations are completed, tighten all the bolts again. When checking the operation, make sure that the brake disc DOES NOT tilt or move when pressing the brake lever.
PADS FOR V-BRAKE BRAKE SYSTEMS
There are such types:
Disposable. their design consists of a bolt with spacer washers of a metal plate and a rubber base. They have a short service life, but also inexpensive.
Cartridge. their design consists of a bolt with spacer washers of a metal plate and cartridge pads, which are removed by pressing the split pins. The rubber base can be replaced.
There are pads for both dry and wet weather. You can determine the degree of wear of the rim brake pads using special marks (grooves).
Worn pads should be replaced promptly to avoid damage to the rim. Note that both cartridge and disposable pads are suitable for V-brakes. And here the rule applies. the more expensive, the more effective.
HOW TO INSTALL disc brakes on your bike YOURSELF
Before considering how to install disc brakes on a bicycle, let’s understand a little what a hydraulic disc brake system is.
As a rule, the components of a disc hydraulic brake are: a brake lever, a hydraulic line, a rotor (brake disc) a caliper (having reservoirs for brake fluid, under the pressure of which the brake pads come into contact with the rotor), an adapter by means of which the caliper is attached to the bike frame.
Hydraulic disc brakes have a significant performance advantage over mechanical disc brakes. This is due to the fact that the fluid in the hydraulic line does NOT change its density, but does not compress and does NOT deform, unlike a mechanical brake cable.
There are open and closed types of hydraulic brakes. The disadvantages of closed ones include the need for adjustment during operation.
A decrease or increase in the volume of brake fluid, for example, due to the influence of temperature, causes the need to adjust the position of the brake pads. Also, brake pads should be adjusted when partial wear occurs.
Open brakes do not have this problem. Since their design provides for an expansion tank filled with brake fluid (usually located in the brake lever). Such brakes do NOT require adjustments during operation.
The presence of modulation (smooth movement of the handle at the beginning of the stroke and powerful adhesion of the pads to the rotor at the end) is influenced by the number of pistons in the caliper.
When it comes to choosing a particular model, it makes sense to consult with its owner. After all, different riding styles require different braking systems.
Cross country athletes are suitable for smooth and light, in downhill or freeriding. powerful and well controlled, in dirt jumping. with good modulation and, at the same time, as light and powerful as possible.
After the first adjustment, the brake disc pads themselves take the correct position. But this does not apply to models with one piston. They require regulation, almost like mechanical ones. For example, Hayes Sole. This model is not considered the best among hydraulic brakes.
The preliminary preparation of open type hydraulic disc brakes is as follows:
- The brake system must be filled with oil. Shimano brakes use mineral oil. Avid, Hayes, Helix brakes use DOT brake fluid.
- The process of pumping the brake consists in squeezing out air from the hydraulic lines, cylinders and brake Bachkovo, drives oil through them.
- Then the caliper is set in such a way that the brake pads do not cling to the rotor.
- Install disc brakes on a bicycle in the following sequence:
- Fasten the brake levers to the steering wheel and adjust their position with the hexagon;
- We install the rotor on the hub, put the wheel in place, tighten with bolts or eccentrics;
- We fasten the adapter firmly, it is possible to use a thread lock;
- We install the caliper, but do not tighten the hexagons, so that it would “float”.
- Pressed the brake lever, check if the brake pads extend equally when pressed.
- Clamped the brake disc with pads, the caliper will be in the right place. To help him, you should try to spin the wheel back and forth.
- Tighten the bolts alternately. If the bolts were very loose, you will have to smoothly release again and press the handle sharply.
- I pressed the caliper, you need to press the handle sharply 15-30 times to bring the pads to the brake disc at the working distance.
- With the handle released, we spin the wheel and check if there is rotor friction in any of the pads. If there is, you need to loosen the clipper bolts and slightly move it towards the rubbing pad.
- Then we tighten the bolts back and check if there is a need, we repeat the above steps.
Mechanical disc brake adjustment
- Since mechanical disc brakes are more sensitive to wheel axle misalignment, bolts or cams should be tightened while sitting on the bike or by pressing down on the front shock. Otherwise, in the future, making small jumps, while riding, friction of the rotor into the block may appear.
- We tighten the adapter tightly. The caliper is installed using the instructions above. One of the pads is pulled out by screwing the screw half a turn, which adjusts its position.
- In Hayes brake systems, before performing this operation, you need to unscrew the locking hexagon, and after all the adjustment is completed, return to its original position.
- Gently press the caliper against the rotor so that its plane coincides with the plane of the fixed pad.
- Then we tighten the caliper mounting bolts alternately. The above actions are carried out with the jacket and cable disconnected. Make sure that the plane of the pad does not move towards the plane of the brake disc.
- We tighten both hexagons and return the pad adjusting bolt to its original position.
- After that, we spin the wheel, checking for friction. If there is friction, the static block can be pushed out slightly with the adjusting bolt and vice versa.
- Presses the movable block, pulling the lever to which the cable is attached. In this case, the rotor will be slightly displaced towards the static pad, but slightly!
- We put the cable and the shirt in the desired position in the lever, the outer block must be pressed. Tighten slightly Corresponding bolt.
- Gently press the brake lever until the start of the working stroke, from which the cable will be in the desired position in the lever. We tighten the fastening of the cable and check the pads for friction. We twist the adjustment on the handle a little, if the shoe rubs and vice versa.
The brakes need to be adjusted so that the adjustment on the handle is minimally unscrewed, therefore, it is better to correct the position of the cable on the caliper lever. So the thread of the handles will be protected from damage.
Organic Brake Pads
They are composed of organic matter and rubber.
- Low noise;
- Lapping is fast;
- Best modulation level;
- Transfer heat to the rotor, protecting the caliper from overheating.
- Less service life;
- Work less efficiently on wet, muddy tracks.
It is preferable to use a light rider in disciplines that require frequent and prolonged braking like XC. Sensitive braking due to good modulation.
Due to the softer composition, wear occurs faster. NOT suitable for use on a muddy track, as even the smallest dust will impair their performance.
How to install v-brakes on an old bike
We continue the cycle theme. This time we will do something more serious than dismantling the wheels. Installing a v-brake (modern hand bike brake) on an old Soviet bike fork. The same Kama acts as a test sample “fig knows what year”, which of course does not provide for fasteners on the fork.
The easiest option. Weld two nuts. But if there is no welding machine, then I will tell you how to make simple fasteners without injuring the fork! Before starting work, I recommend that you familiarize yourself with the principle of operation of v-brakes on a live sample. Drill the fork cannot!
1) We buy v-brake brakes. NOT cheap Chinese meat, but an average level with a minimum of nuts.
This is how a half of a normal take-break looks like (if it is in Russian). The brake is universal, there is enough height to fit a classic low wing. I will not say about any plastic nonsense.
2) The brakes can be mounted on a metal horseshoe, and then clamped on the fork (as is the case with modern forks), or simulate welded blanks. Let’s dwell on the second option and make a clamp from duralumin plates.
Dural or duralumin. Soft alloy, and this is its advantage, because the clamp will be easy to pull off, and it will repeat the entire contour of the fork strut, which means. Will sit tight and DO NOT remember her. By the way, the duralumin is cut with metal scissors without any problems, the grinder is not required.
3) Drill a strip of duralumin in three places, try on a fork and cut:
You should NOT thread the screw (as in the picture), namely the head bolt, so that the tapered walls of the strip clamp it.
These are the bolts:
The length of the bolt should be taken taking into account the depth of the brake, a few washers and nuts. The thickness is not particularly important, it can be well shrinked.
In the final form, the clip for one fork post looks like this:
Here, while making the clamp, I try on the brake fit:
There is another moment: there is a return spring in the brake half. For her, you can immediately figure out the fixation on the clamp, but I did not bother and pulled it back with a clamp on the fork.
4) turning the bike over and start dancing by positioning the clamp:
I marked the height with electrical tape. I put the clamps in the opposite direction, as on steep components =). It is necessary to pull the nuts well in order to exclude the slightest backlash. As I wrote above, the duralumin is superbly pulled together.
5) mount the cable. The rubber grip on the handlebars of a Soviet bicycle is removed with a thin screwdriver and such and such a mother. Pouring water is not necessary:
You just need to pierce in a circle to form air blockages and turn it well.
We put the brake lever, put the rubber band back on (you can drip oil on the steering wheel for the chain (then wipe it slightly with a rag) so that the handle goes back more easily), if it turns, you can put it on a selikon (not required):
Fastening the cable to the brake halves, adjust the linings, debug: