How to unscrew the bicycle cranks by yourself?
Probably, no part of the bike has more load than the connecting rod. On the models of the last years of production, for their manufacture, instead of steel, various alloys began to be used. This makes the structure lighter and more robust. Sometimes, to reduce weight, the connecting rods are made hollow, they are also made of composite material, which somewhat increases the cost of the bike itself, but also greatly facilitates it.
On inexpensive models of bicycles, a non-separable block of connecting rod-stars is made. An inconvenient and impractical option, because when replacing the sprockets, you will have to change both connecting rods at once. If you started to repair the carriage or replace the stars, we recommend that you immediately replace both connecting rods with a design that involves a detachable connection of the connecting rod and sprockets.
When is it necessary to dismantle the connecting rod
The connecting rod does not imply any maintenance and special care. Its replacement is carried out only in the case that we described above and in case of mechanical damage. The need for dismantling arises when we need to get to the carriage or completely disassemble it for lubrication, flushing or adjustments.
Also, sometimes after the rain, an unpleasant creak occurs, which is caused by the ingress of sand into the connecting rod-shaft interface. In this case, you have to disassemble it and clean the seat.
A special device that is designed to dismantle hard-to-remove parts is called a puller. This is a no brainer. In our case, to remove the connecting rod from the bicycle carriage shaft. It looks like this.
This type of connecting rod puller provides the ability to remove the pedal as well.
The connecting rod is held on to the shaft by a heavy-duty 8mm head bolt. It is not difficult to unscrew the bolt. But the difficulty is that the connecting rod sits on the shaft with a slight interference fit and has a tapered fit. Very often, in wet weather, water and dirt penetrate into the interface between the connecting rod and the shaft. Then it sticks to the shaft and it is almost impossible to remove the connecting rod. But in our toolbox, of course, there is a puller for connecting rods, which is a complex turning part. a screw with a two-level head for an open-end wrench and a socket. A cunning nut with external and internal threads is screwed onto the screw. It takes a long time to explain, but in the photo everything is very clear.
- Before starting the process, sprinkle the mating point of the connecting rod and shaft with a magic solution of WD-40. It will dissolve the remaining dirt and make the process easier. You can just as well use BSK brake fluid if it is lying around in your garage. You can do the same if the bolt does not unscrew.
- Important! Make sure that the puller rod is less than the diameter of the square on which the connecting rod is fitted. Otherwise, the operation will fail. the thread will break.
- Unscrew the mounting bolt.
- We screw the puller into the connecting rod to the limit, making sure that the puller rod is unscrewed as much as possible.
- We tighten the puller bolt smoothly and without jerking, otherwise there is a risk of damaging the thread.
Here is a step-by-step photo guide explaining the process visually.
Dismantling without puller
In this case, scientific and technological progress offers few options.
As you can see, we cannot get away from advanced technologies and progressive methods. Even in such a seemingly trifling matter.
How to remove the bottom bracket from a bike without a puller?
Despite the fact that a bicycle is a simple structure from a technical point of view, it still needs to be checked and carried out technical equipment and all kinds of maintenance. With the help of these procedures, you can greatly extend the life of your device. In addition, if you follow all the norms and more often look closely at the condition of the bike, then you can warn it against significant types of repairs, which are also quite expensive.
It is worth noting the fact that there is absolutely no need for minor repairs or inspection of the bike to contact service centers. In this article we will tell you how to remove the carriage from the bike, due to which you can save on service centers. Consider all the direct nuances of this process and other things that you definitely need.
Carriage removal process for a beginner
Undoubtedly, it is always difficult for a beginner in this or that business. But if there is a certain desire to do something with your own hands, then you need to learn and do. We present you with a description of how to remove the carriage from a bicycle with your own hands.
Doing so-called maintenance on your own vehicle is better than trusting a stranger. After all, you will clearly know what works great in your device and what needs to be eliminated. If you have the necessary tools for various work with the bike, then you can carry out a number of actions yourself.
In order to remove the carriage from the bike, as well as remove the pedals from the bike carriage, you need to prepare in advance a number of tools that will be at your fingertips. These tools include:
- a wrench for nuts or an adjustable character;
- for connecting rods, a special squeeze is required;
- flat-type screwdriver;
- hammer, but small;
- a tool that will allow you to remove the carriage itself.
On a device such as a bicycle, the carriage is a bearing assembly. The main essence of such a mechanism is to connect the connecting rod to the frame. In addition, a product such as a carriage provides so-called torque to the connecting rods. Based on this, it can be understood that such a detail is very important on a bicycle, its condition affects a lot.
The design of modern bicycles implies a special glass for such material as the carriage. This glass can be found in a specific area of the rear pipe. As a rule, manufacturers install a carriage cup in the area of the rear stays. Due to the fact that the device is installed in such a vulnerable area of the bicycle, its durability is poor. From this it turns out that there is a need to check the device and repair it from time to time.
It is negatively affected by dirt, dust and rain. For this reason, backlash is formed. If you do not clean it in time and prevent damage to this product, then this threatens with a lot of negative nuances. During movement, you may encounter a decrease in potential speed or jamming of the device.
Therefore, advice on how to remove the carriage from the bike is quite relevant.
The characteristic qualities of this type of repair
Every bicycle owner should know how to remove the carriage from a bicycle. It is worth noting that if the manufacturers of your bike have installed such a closed-type mechanism in it, then there is no point in repairing it. Such devices are usually disposable and the best way out of this situation. replacement of the old unit with a new one.
In the same case, if your mechanism is open type, then everything is somewhat different. It can be easily removed, repaired and installed in its place. Bicycle repair experts say that a bottom bracket. a fairly simple mechanism that can be easily repaired.
When carrying out repairs, a number of steps must be taken:
- It is necessary to lubricate all parts that are present in the mechanism.
- Backlash must be eliminated.
- If there are any sounds when driving, then they should be eliminated.
Convenient instructions for removing this carriage
A lot of people are wondering how to remove the bottom bracket from a bicycle without a puller. The question is quite interesting, but first, let’s look at the instructions for the standard process. It is important to remember that the design of this product contains small bearings, which often crumble. Therefore, you need to understand that it is necessary to carry out the removal and repair with accuracy and care.
Before you know how to remove the carriage from a mountain bike, you need to learn about the puller tool. It must be selected taking into account the appearance and structure of the carriage itself. Often the carriage manufacturer must match the puller manufacturer. Today, there are universal types of puller in the world, but, unfortunately, they may not be suitable for one or another mechanism. This mechanism is excellent for removing so-called carriage cups. This is precisely the main feature of the mechanism. Therefore, when using such a device, you should be extremely careful and attentive.
And how to remove the carriage from a bicycle without a puller?
How to remove the carriage on a speed bike. this is a separate topic. This is justified by the fact that on such a vehicle, this device has a slightly different form.
On other bicycles where the bottom bracket is of the standard type, it should be externally checked. If it is disassembled, then that is good. But before starting this procedure, you should pay attention to the condition of its bearings. In order to clean the carriage itself and especially its threads, it is necessary to use gasoline. It is important to remember that such devices need regular cleaning, this is necessary for your safe driving.
Putting the material in its place
After cleaning the material, the work does not end. The carriage must be attached and reinstalled. This process also brings with it a number of complications, which involve placing the cups in place. After installation, the device must be lubricated. That’s it, now you know how to remove the carriage from the bike.
The homemade carriage on the bike I assembled consisted of an axle and two 203x bearings driven tightly into the frame. Those were the times 🙂 Now the carriage has become much more complicated. Let’s try to deal with this tricky thing.
The bottom bracket is a bicycle assembly that connects the system to the frame and rotates freely using bearings (usually cartridge bearings). The carriage is screwed or pressed into the carriage glass of the frame.
Separately, eccentric carriages can be distinguished. they can be displaced in the carriage glass of the frame in order to tension the chain on a singlespeed or on a bicycle with a planetary hub. Requires a special frame.
Are part of an integrated system. They are two cups with bearings pressed into them, screwed into the bottom bracket of the frame. In this case, the bearings, as a rule, are located outside the carriage sleeve, and the axle is pressed into one of the connecting rods and has a greater thickness, which achieves a high rigidity of the assembly. The cups are interconnected with a plastic or aluminum spacer that provides bearing preload and protection from dirt.
Road and mountain carriages, as a rule, are incompatible with each other, even from the same manufacturer.
Integrated carriages standards:
- Shimano Compatible:
- Shimano Hollowtech II
- RaceFace X-Type
- Chris king
- FSA Mega Exo
They include an axle onto which the connecting rods are pressed, and a set of bearings located inside the bottom bracket of the frame. They are divided into two categories:
- Cartridge. axle and bearings are a single non-separable unit.
- Dismountable. can be disassembled for cleaning, lubrication and replacement of worn parts (used in old bicycles).
Non-integrated carriage standards:
- Wedge-fit connecting rods (Soviet bicycles).
- Under the square (square taper). the standard “floats” somewhat from different manufacturers.
SQR. square connection
Octalink. Shimano standard
All of these standards are generally incompatible with each other.
Types of carriages according to the used carriage glass
Depending on the carriage glass of the frame, carriages are divided into the following types (the most common):
- English thread (BSA, 1.37 in x 24 TPI) is the most common standard. Options depending on the length of the glass:
- 68 mm. most common,
- 73mm. used on a range of mountain bike models,
- 83 mm. for extreme disciplines,
- 100mm. fat bikes.
- With Italian thread (BSC, 36 mm x 24 TPI), tube length 70 mm. used in old road bikes. Still (2013) in use by Campagnolo.
- With French / Swiss thread M35 × 1. used in Soviet bicycles.
Recently, integrated systems such as BB30 / Press-fit are gaining popularity. Design feature. bearings are pressed directly into the frame (plastic cups can be used), an aluminum axle with a diameter of 30 mm is threaded through them (instead of a steel one with a diameter of 24 mm). This promises a further increase in the rigidity of the knot with some weight reduction. On the other hand, bearing replacement tools are significantly more expensive than conventional carriage pullers.
Classic Press fit for BB30 30mm axle systems:
- BB30: cup inner diameter 42mm, cup width 68mm for highway or 73mm for MTB, bearings without cups.
- Press fit 30 (PF30): inner cup diameter 46 mm, cup width 68 mm for highway or 73 mm for MTB, bearings with cups.
- Press-fit carriages for standard systems with 24mm steel axle:
- BB90 / 95: cup inner diameter 37 mm, cup width 90.5 or 95.5 mm, bearings without cups.
- BB86 / 92: cup inner diameter 41 mm, cup width 86.5 or 91.5 mm, bearings with cups.
- Unique standards requiring their own 30 mm axis system:
- BBright Direct Fit: cup inner diameter 42 mm, cup width 79 mm, bearings without cups.
- BBright Press Fit: Cup Inner Diameter 46mm, Cup Width 79mm, Bearings With Cups.
- 386 EVO: bowl inner diameter 46 mm, bowl width 86.5 mm, bearings with cups.
Allows the use of a drive without external gear shifting (singlespeed, planetary hub) in conjunction with conventional vertical frame dropouts. These dropouts provide a faster and more comfortable wheel positioning compared to horizontal ones. The eccentric carriage is rotated in its seat, allowing the chain to be tensioned, then fixed with bolts and / or union nut. On serial bicycles, such carriages are rare, one of the most common examples is the Strida. Also usually installed on tandems as a front carriage, which makes it possible to tighten the timing chain.
- 54mm standard. for example, Bushnell Eccentric Bottom Bracket. Has BSA thread for standard BB, requires special frame with 54 mm seat.
- Standard 46mm. Fits into a standard Press Fit 30 frame. Integrated system (24mm axle) fits directly into the carriage.
- BSA Standard. Fits into standard BSA threaded frame. The integrated system (with a 24 mm axis) fits directly into the carriage. Provides chain length adjustment only within 1/2 link, requires use in conjunction with a half-link chain.
http://www.bike-repair.ru tells in great detail about the repair of carriages and how and how they can be removed. Let’s deal with this issue too.
To work with the carriage. the cartridge requires only a slotted wrench. It is also useful for many collapsible carriages.
But on some collapsible carriages, instead of a slotted one, another key is required.
And this may be required. You can do with a regular open-end wrench for 36, or in extreme cases, use an adjustable / gas wrench. Use the gas wrench carefully. you can easily damage the frame.
On collapsible carriages, you will also need such a special key
Despite such a variety of tools required, the process of disassembling, installing and adjusting carriages of different types does not differ in variety. You just need different tools to perform the same operations on different carriages. The main difficulty when disassembling the carriage is not to forget that a left-hand thread is used on the right side. The second difficulty. especially with aluminum frames. can be very, very hard to unscrew the cups. In this case, the key should not be allowed to break. you can damage the bike parts or injure your hands. Therefore, it is better to stock up on keys with sufficiently long handles.
Removing the carriage of cartridge and collapsible types
Before removing the carriage from the frame, both connecting rods must be removed from the carriage axis.
The bottom bracket should then be cleaned of any dirt, as the frame bottom bracket is one of the dirtiest places on a bike and is usually difficult to clean until the cranks are removed. It is especially necessary to scrub the dirt out of the cup slots carefully. if there is a lot of dirt, then it is impossible to insert a stripper into the cup.
It may be necessary to use considerable force when removing the carriage. Therefore, the bike must be securely positioned. If it is more convenient for you, you can turn it upside down.
We begin to remove the carriage from the left side, that is, where there are no stars.
Some carriages have a lock nut on the left side. It must be turned off special. key (if it is not there, then it is possible with an ordinary family member). This nut has a right hand thread. Unscrewing may require considerable force. It must be unscrewed carefully, not allowing the key to break off. you can damage the nut.
If your carriage does not have such a nut, then go to step 2.
Now we take the key for the carriage (slotted or special, depending on the design of your carriage. The pictures show the slotted one.) Insert it into the grooves, and turn the left adapter cup out of the frame with an adjustable wrench with a longer handle. It has a right hand thread. Unscrewing may require considerable force.
We take out the left cup (together with the bearing, if the carriage is collapsible)
We pass to the right side of the bike (where the sprockets are). Again we take the carriage puller and the long-handled key, insert it into the grooves, and turn the right cup out of the frame. It has a left-hand thread. Unscrewing may require considerable force.
We take out the cartridge or the right cup with the axis.
The carriage is removed. Now you need to pull out the bearings from the collapsible carriage (if they are not pressed into the cup), remove the old grease with a rag, and rinse all the parts in some kind of solvent (usually kerosene).
Installation of the cartridge-type carriage is performed in the reverse order of removal.
We start by applying a little lubricant to the carriage and adapter cup threads, so that later it will be easier to turn it out.
We start on the right side. Using the carriage wrench and an adjustable wrench, screw the carriage into the frame until it stops. The moment should be 50-70 Nm.
The carriage on the right side has a left-hand thread.
We pass to the left side. Use the same key to screw in the left adapter cup. The cup on the left side has a right-hand thread. The moment should be the same. 50-70 Nm.
Now you need to install the rods and the system.
Assembly and installation of a collapsible carriage
The collapsible bottom bracket is very similar to the one used on Soviet bicycles, so the assembly and adjustment process is not difficult.
Before assembling, rinse all parts in some solvent (kerosene), wipe with a cloth and dry. I do not recommend using gasoline. it can damage the plastic seals in the cups. The new carriage should also be washed. the grease on it is most likely a preservative.
It is also a good idea to check the frame BB for damage and any debris. Several times I found shavings there, sawdust, which fell into the carriage assembly from the seat tube of the frame. When caught in the bearings, the sawdust will not contribute to the easy ride of the bike.
The carriage is installed in the reverse order of removal.
When assembling the carriage, the most difficult thing is not to confuse the ends of the carriage axis. its right and left sides are different. Usually on the axle or on a plastic casing (on some carriages this casing is not provided) letters are applied corresponding to the sides of the axle.
The cups cannot be confused. they have different threads (the left cup has the right one and vice versa)
We put the plastic cover on the axle. We put the bearings in the cups. If the bearings have cages, then we lay them out with a cage (balls. inside the cups). Lubricate the bearings with thick grease With the same grease we lubricate the threads of both cups.
We start assembling from the right side. We insert the axle into the right cup, and screw this cup into the frame until it stops. This requires a slotted wrench for the carriage. The right cup has a left hand thread.
Now we screw the left cup in the same way on the other side. It has a right-hand thread. Let’s move on to adjust the carriage. (you can go directly to step 1)
Adjusting the split carriage bearings
After assembly, the carriage must be adjusted, but often it is necessary to adjust without disassembly. For example, sometimes after a long drive on uneven roads, a play appears in the carriage, which should be eliminated by adjusting. Backlash in the bottom bracket can, at best, lead to poor shifting accuracy and, at worst, damage to bearings and cups. On a long trip, you can try to adjust the carriage without disassembling.
Before starting the adjustment, you need to remove only one left connecting rod, remove the lock nut (with a special wrench) and slightly loosen the left cup (with a slotted wrench). Nut and left cup have right hand threads.
We turn the left cup almost all the way so that the carriage axis rotates easily, without jamming, and at the same time has no backlash. Then we loosen it with a slotted wrench by about a quarter of a turn.
Screw on the lock nut while holding the cup with a slotted wrench. We tighten the nut special. key all the way.
Now you need to rotate the carriage axis by hand, and shake it from side to side. If everything is done correctly, the carriage should rotate freely, without jamming, and not have a noticeable backlash. If it sticks, or there is a backlash, then unscrew the lock nut, and repeat step 1, loosening or tightening the cup with a spline wrench.
When the carriage rotates without jamming and backlash, you can put the connecting rods.
Sometimes the carriage cannot be adjusted. That is, when you want it to rotate freely, then there is a backlash. Conversely, if you eliminate the backlash, then the axis rotates tightly, with jamming. This suggests that it is time to change either the bearings or the carriage itself.
How to remove pedals from a bike without a puller?
Bicycles are the most popular and convenient form of transport. For some, this is recreation, sports and a great way to attract attention, for example, while performing original stunts on a two-wheeled bike. However, do not forget about timely maintenance and repair. That is why many cycling enthusiasts are faced with the problem of how to remove the pedal from the bike. Having penetrated into the structure of transport, you can easily learn how to carry out repairs yourself. Thus, it will be possible to avoid various unforeseen breakdowns.
How to remove the pedal from the bike and replace the connecting rod
The pedal is a simple part, but the long life can cause some disassembly problems. Therefore, many experts recommend systematic maintenance of the vehicle, despite the fact that many do not attach importance to this issue.
Let us analyze in which cases it is necessary to remove the pedals:
- the part is damaged and requires replacement;
- lubricate the elements;
- replacement or repair of the connecting rod;
- you need to understand the features of the system and understand how it works.
Before removing the pedal from the bike, the following tools should be prepared:
- open-end wrench 15;
- adjustable wrench;
- if there is a non-standard solution of the manufacturer in the fastening elements, then usually the set contains a key for removing the pedal.
All pedals, despite their different features, have a common design:
- Platform. the surface on which the foot rests, which is fixed on the axis.
- Metal axis. a pin made of metal. Has a thread and is screwed into the connecting rod.
- Bearings. provide torque. Serves as a connecting element between the axle and the platform. There are simple bulk and cartridge bearings that differ in weight and quality.
- Bolts, nuts.
It should be noted that the design of the pedals is not as simple as it seems at first glance. Therefore, before tackling such problems, for example, how to remove the axle of a bicycle pedal, you should carefully study the overall design.
There are the following types of pedals:
- regular (platform);
Each of the pedal types has its own specifics: the first is created for any footwear, the contact type exists for grip with sports shoes and the universal third type, which has a platform on one side and a clutch mechanism on the other. The method of disassembly depends on the type of part. The mechanism of conventional pedals is simpler and faster to disassemble.
Removing the pedal from the bike: step by step instructions
So, let’s look at the main steps on how to remove a pedal from a bicycle without a puller:
- Use a screwdriver to remove the plug from the end of the part.
- We unscrew the platform from the connecting rod using an adjustable wrench. Right pedal counterclockwise, left pedal clockwise.
- We unscrew the control nut. At the same time, we hold the connecting rod axis with the second key.
- Remove the washer located at the end of the pedal.
- We remove the platform from the axle and at the same time hold the bearings. Dismantling ready.
With clipless pedals, the circuit is a little more complicated. Therefore, before removing the pedal from the bike, you must have a special device. The connecting rod has a thread into which the puller is screwed in and begins to squeeze the connecting rod from the axis. At the end of the work, we put the pedal in place, check the strength of the part, and install the plug.
Constant mechanical stress on the pedal can cause rotational problems. To quickly deal with them, it is necessary to heat the connecting rod and axle. As a result, the process of metal deformation will occur. This will help to easily remove the axle.
To prolong the life of the pedal, use a chain treatment agent. Thanks to the solvent, stubborn dirt such as bolts can be removed. We use a solvent and a rag (napkin). The solvent in this case can be replaced with kerosene. Also, do not forget about the toxicity of these funds.
The manufacturer attracts with serious equipment and carbon frames (StelsNavigator 890DCarbon). An amazing aspect is the attractive price-performance ratio.
How to remove pedals from a Stealth bike
It is necessary to remove pedals from a high-speed Stealth bike in the following situations:
- during scheduled maintenance;
- if there is a crunch or other squeaks;
- replacement with new pedals.
To do this, you need an 8 socket wrench, grease and a napkin. So, after removing the pedal, you need to take a rag and wipe the threads in the connecting rods. Now you can disassemble the pedal. While holding the axle, loosen the nut at the other end with a collapsible wrench. We remove the axle and carefully remove the bearings. Soak all parts in gasoline for a while and wipe with a napkin.
After completing the preparatory stage, you can proceed to the work itself. Please note that there is a significant difference between how to remove pedals from a bicycle with and without a puller.
So, first grease the bearings liberally by placing them with balls inside the pedal. Then put on the axle, screw on the cone and the control nut. Adjust light rotation before finishing work, without backlash. When you get the desired result, you can screw the pedals to the cranks, not forgetting to lubricate. On this, the work can be considered completed.
Therefore, before removing the pedal from the bike, it is advisable to study its construction, paying particular attention to the main elements. It is highly recommended that you read and understand the accessories of all parts and familiarize yourself with the safety precautions. Indeed, driving safety and human health depend on competent assembly and technology. It is important to take a responsible approach to the question of how to remove the pedals on a high-speed bike, due to the complex design of this vehicle.
Bicycle carriage: where is it, functions, how to remove
Cyclists who rarely go out for a ride have probably not even heard of what a bicycle carriage is. Even if they have heard, they do not know where she is and what she is. But for those who often use the bike for their own purposes or are engaged in cycling, this knot is of great importance. What is a bicycle bottom bracket, what functions it has and how to fix it now and find out.
What is a carriage assembly? This mechanism is almost the main thing in the whole bicycle. He will not go anywhere without him. Where is he located? It is located in a glass (this is such a special place), namely, where the connecting rods are. The main task is to secure those same rods together and connect them to the frame. Without it, the cyclist simply cannot pedal, which means, move forward.
Bicycle carriage device
What does this node consist of and what is it like? Bicycle models are different, so the carriages are also different from each other. The standard is sixty-eight millimeters, but there are also one hundred and ten, one hundred thirteen and so on.
Also, bicycle carriages are divided into two types: collapsible and cartridge (non-collapsible). Each type has its own pros and cons. Let’s start with cartridges. This type cannot be repaired. this is its main feature. If the mechanism rusts or breaks, then it can only be thrown away. But they also have a big plus. They are very durable. Such a bicycle bottom bracket will last as long as its bearings do not wear off. The mechanism is hermetically sealed, so foreign objects in the form of dust, sand, water and the like do not get there, thereby protecting it from rapid wear. Such carriages behave very well even after long-term operation in difficult conditions, so manufacturers often like to install them on mountain bikes.
Collapsible carriages are a slightly different device. In essence, this is just the axis on which the bearings are mounted. In this case, the owner needs to check this unit at least sometimes and, if necessary, lubricate and replace the damaged bearings. Such care will significantly extend the life of the mechanism.
How to identify a faulty carriage?
No mechanism lasts forever, especially if not monitored. That is why, sooner or later, the carriage mechanism will malfunction. How to determine the malfunction? In general, it is not difficult. You just need to be careful. The first sign is heavy driving. If it suddenly becomes difficult to pedal, then perhaps this is a malfunction of the carriage. The accumulated dirt does not allow the mechanism to function normally, so it becomes difficult to drive. Squeaks and knocks are also characteristic. Jumping and heavy physical exertion can skew the axle or break the bearings. In this case, there will be a backlash.
If, when riding while standing, the pedals begin to jam or squeak strongly, then this is a sure sign of a malfunction. There is already a need for repair of the bicycle carriage. Or just replacing the node with a new one.
Removing the carriage from a bike?
So, to repair the mechanism, you first need to remove it, remove it from the glass. Before starting work, it is necessary to clean the area around the carriage. Remove all adhering dirt and dust. All this is done in order not to bring all the garbage inside later.
How to remove the carriage from the bike? First you need to remove the plugs that close access to the connecting rod nut. To quickly get to the mechanism of interest, you need special keys: a connecting rod squeeze and a carriage remover.
First you need to insert one end of the connecting rod squeeze and unscrew the nut. Then we insert it with the other end and screw it in by force. In this way, the connecting rod comes off the axle and can be removed. The same must be done on the other side. It is best to start work from the side where there are no stars.
The next step is to remove the carriage. This is where a special renter comes in handy. We insert it, and on the other side we put on a wrench. With a little effort, you can reach the device. We carry out similar actions on the other side. The carriage is now ready to be removed. If the device is in more or less decent condition, then the matter will only manage with lubricating the bearings. For this, it is best to use thick lubricants. Bicycle bottom bracket assembles in reverse order.
Switching speeds on a bike. What is gear shifting for?
Riding on a flat road, uphill or downhill requires different efforts from the cyclist. On a single speed bike, there are no options, since there is only one gear. And those who have experience climbing a mountain on a single speed bike know how difficult it is. But in the case of a multi-speed bike, new possibilities appear. you can adjust the load. On a bike equipped with multiple gears, for example, it is much easier to ride uphill. Let’s figure out how the gearshift occurs.
What is gear shifting
The essence of switching speeds is to drag the chain from one star to another. And various combinations of chainrings and chainrings allow you to adjust the cyclist’s load. But first, let’s turn to the bike drivetrain.
The transmission is all the parts and assemblies of the bicycle that transfer energy to the rotational movement of the rear wheel. The transmission consists of a carriage, a crankset, a chain, sprockets or cassette (or ratchet), front and rear derailleurs, as well as shifters (they are also sometimes called shifters).
Gear shifting occurs via shifters located on the steering wheel. Using the rear derailleur shifter, located on the right handlebar, the chain is thrown between the rear sprockets, and using the front derailleur shifter (it is on the left handlebar) between the front sprockets.
Most multi-speed bikes have three drive sprockets and six to eight driven sprockets. The fore stars are counted from small to large, and the rear stars, on the contrary, from large to small.
Types of speed switches
There are two main types of speed switches. external and internal shifting.
Internal switching mechanism
City bikes often use an internal gearshift mechanism that is hidden inside the rear planetary hub. Planetary hub bikes have only one chainring and one sprocket. The number of speeds / gears in planetary bushings is usually from 3 to 7. The planetary hub has a rather complex internal structure.
Pluses of planetary bushings: they withstand adverse weather and road conditions well, since the mechanism and all its parts are enclosed in a case and, as a result, are reliable and durable; you can switch speeds without pedaling.
Cons of planetary bushings:. heavy weight;. very difficult repair, impossible in field conditions.
External switching mechanism
This type of derailleur is used on most multi-speed bikes, from city bikes (eg Forward Dortmund 28 2.0) to mountain bikes (eg Forward Apache 27.5 2.0 disc). Gear shifting is carried out using the front and rear derailleurs.
Front derailleur The front derailleur transfers the chain between the chainrings. The derailleur design has a moving frame within which the bicycle chain runs. When shifting gears with a shifter, the frame moves and becomes above the desired sprocket, which ensures the movement of the chain to this star.
Rear derailleur The rear derailleur is a spring-return mechanism that moves a frame (or foot) with rollers between them within a transverse axis. In one direction, the switch is moved with a cable, and in the opposite direction, with a return spring. When you move the derailleur, the chain passed through it is thrown from one rear sprocket to another, and the chain tensioner automatically removes the chain slack.
Advantages of external switches: simple design low weight low price high number of gears
Disadvantages of external derailleurs:. highly susceptible to unfavorable external factors. need for adjustment and maintenance. risk of breakage if the bike falls. it is impossible to change gears if the bike is stationary
Correct star combinations
Choose speeds based on the terrain and your physical capabilities, and so that the chain does not tilt. You can make sure that there are no distortions simply by looking at the chain. If it moves parallel to the frames of the front derailleur, then the selected speed is optimal. Skew occurs when the chain is on the front large chainring and on the rear, also large.
Let’s see which sprocket combinations are applicable on a bicycle with three chainrings and eight chainrings. The main principle is simple: it is necessary that the combination of front and rear sprockets is always approximately in the same vertical plane.
The large chainring is matched with 4-8 rear chainrings. This combination is optimal when riding on a flat road.
The middle chainring is matched with the 3rd to 6th chainrings. This combination is suitable if you are riding on lightly rough roads, or if you want to give yourself more physical activity while riding on a flat road.
The small chainring is matched with 1 to 3 rear sprockets for uphill climbing. In this case, much less effort is required from the cyclist when pedaling, but more frequent pedaling.
Incorrect combination of front and rear sprockets, leads to a strong misalignment of the chain, shortening the life of not only the chain, but also the derailleurs.
How to adjust the speed switches. How to switch gears correctly
Correct gear shifting allows you to ride easier and more comfortable with less effort, as well as increase the service life of all elements of the bicycle transmission. We have prepared several rules and recommendations on how to properly switch speeds on a bike: