How to disassemble a bicycle bottom bracket
Remove cranks without tool no damage
To begin with, it would be most correct to consider what a bicycle bottom bracket is and what its functions are. A bicycle bottom bracket is a bearing device that connects the crankset to the frame. Thanks to this device, a special function is provided in the bicycle that regulates the torque that rotates the bicycle cranks. The location of the bike carriage. in the lower part of the vehicle, and because of this, it is highly susceptible to various kinds of pollution, this very often makes it inoperative. When dust or dirt enters the carriage, it begins to make sounds similar to crunching or crackling, which is the first signal that it needs to be disassembled, cleaned and put in order.
Types of carriages
There are two types of bike carriages. The first of them is a closed type, they can also be called cartridge ones. This type has one significant drawback, due to which the choice can fall on the carriage of the opposite type. The closed view is practically beyond repair, which means that every time it breaks down, the owner will be forced to purchase a new part, which is not such a cheap pleasure. As for the second type. open carriages, they are the most optimal choice for a vehicle, since they can be safely repaired as many times as required. They work thanks to the rotation of the bearings located in the holes of the carriage, and are screwed into a special glass, which is located in the bicycle frame. Thanks to this design, the open carriage is easy to repair, it can be easily removed, unscrewed, cleaned, lubricated, assembled and put in place so that it will serve for some more period of time.
Items that include renovation:
- Scheduled maintenance is maintenance performed regularly to keep your device in working order. It can include elementary lubrication and bulkheads;
- Difficulty rotating;
- Crunching and other sounds emanating from the part.
How to remove the carriage?
So how do you remove and disassemble a bicycle bottom bracket so as not to damage the part? There is a way that you can easily remove, disassemble and reassemble the carriage. As mentioned above, only open-type carriages can be repaired, so this article will talk about them.
Before removing the carriage and starting repairs, it should be remembered that, as a rule, loose bearings are used in such devices, and when you unscrew the carriage, there is a chance that the bearing balls can crumble and get lost. To prevent this from happening, you must very carefully unscrew them with a special key, which can prevent this kind of misunderstanding.
It should be remembered that it may be necessary to apply considerable force when unscrewing, as the carriage is usually very tight. It is necessary to acquire all the necessary equipment and inventory so that the repair takes place in the most comfortable conditions. When removing the carriage, first of all, it is necessary to squeeze the connecting rods. Most likely, you will have to make a significant effort: we take out the bolts that tighten the connecting rods. This is a laborious process because the bolts have a tight nut. It may take considerable effort to unscrew them for sure.
After that, it is necessary to start removing the connecting rods, it is recommended to do this from the side on which the stars are not located. The carriage is mounted on a cup, it also has a left and right cup. During disassembly and repair, you will have to use both the left cup and the right one. This is due to the fact that the right cup is a little more difficult to unscrew than the opposite one. In order to correctly remove the right cup, it is necessary to take care of the thread when unscrewing it, since if it is inaccurate, you can damage it with a screwdriver, which will lead to unpleasant consequences in the future. Having dealt with the device of cups, we turn the cup out of the frame with a slotted wrench. This is the principle of repairing a collapsible carriage and connecting rods.
How to assemble?
After performing the necessary maintenance, viz. lubrication, disassembly, cleaning and repair of the connecting rods, as well as the bicycle carriage, you need to assemble it and return it to its usual position. This is a little easier to do than it is to disassemble, since the construction is already more familiar. All parts must be lubricated and inserted with the opposite side so as not to get tangled. Next, we take the bolt, insert it into the grooves, and then fix the nut. It is desirable if it has a right-hand thread. The cup and connecting rods also need to be lubricated and installed in place. At the end of everything, you should check if the pedals spin well, if they are slightly tight, then you should slightly loosen the nut. Bearings should not be forgotten as well, since there should be the same number of them as was during the parsing. Otherwise, there is a threat that the structure will permanently fail, which will not be very pleasant for the vehicle owner.
Based on the foregoing, it can be understood that a bicycle bottom bracket is one of the most important parts in the design of a given vehicle. This is due to the fact that due to the fact that there are bearings in its design, it takes on the main load when driving. Therefore, one should not forget that the attitude towards her should be careful and accurate. It is necessary to periodically clean it of dirt and dust, check for serviceability, as well as for wear of the balls. As already mentioned, the first signs that something is wrong in the carriage are extraneous sounds. If any, it is best to diagnose and, if necessary, carry out appropriate maintenance or even repairs. For this, you can contact either a professional specialist, or do it yourself, observing all the necessary rules, safety precautions and instructions. By doing all this, you can safely provide your vehicle with a long service life, and yourself. good mood and a little experience in the repair of this kind of vehicle.
DIY bicycle carriage repair video
Removing the carriage: doing it right!
It makes perfect sense to first remove the assembly from the bike frame to fix the problem. To be precise, take it out of the glass. Just about how to do it with your own hands, and the conversation will go.
So, before proceeding with the removal procedure, you will need a set of tools:
- Connecting rod squeeze.
- Wrench. If the size of the nut is unknown, then an adjustable wrench will go.
- Flat screwdriver.
- Small hammer.
- Carriage puller for removing from the glass.
Before proceeding with disassembly, all space around the carriage should be cleaned. A damp cloth removes all dirt and dust from the frame, bottom bracket area and connecting rods. This will be enough so that excess dirt does not get inside during parsing. But it will be better if you wash the whole bike. Cleanliness is the best repair assistant. Proven!
Plugs are removed from the connecting rods. Basically, these are plastic covers that can be easily pry off with a screwdriver and can also be easily inserted back. Next, you need to unscrew the nuts securing the connecting rods to the carriage. A squeeze will help in this matter: we put it on a nut, then we take the key and unscrew it. Depending on the type of thread, the direction of loosening and tightening the nuts may vary. There is an option where the thread is right on the left side (counterclockwise. loosening), and on the right side. left (counterclockwise. tightening). Maybe only right-hand thread on both sides, it will be easy to figure it out.
The next step is to remove the connecting rods. The squeeze is inserted at the other end and twisted into the connecting rod. The squeeze bolt is forcibly screwed into the connecting rod, as a result of which it gradually comes off the axis. It is recommended to start removal from the side where there are no transmission stars.
The bicycle carriage is held in place by means of special cups fixed with rings. A screwdriver is attached to the ring so that its end points to the left. By lightly tapping the hammer on the screwdriver, the ring smoothly turns to the left and jumps off. Similarly, by turning to the left, using the percussion method, the cup is also removed.
So, finally we got to the bottom bracket bearings. These small parts can be removed with the same screwdriver: pry, and they will pop out.
And, finally, a removable device pulls out the carriage shaft from the glass. a rotating part that plays a major role in the mobility of the bicycle cranks.
How to disassemble and remove the bicycle carriage yourself
Perhaps fans of simple periodic bike rides are not familiar with this term, but those who often use a bicycle as a vehicle, and even more so, professionals in the field of cycling, are aware of what a bottom bracket mechanism is.
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Like any mechanism, this part over time is exposed to external influences, wears out or completely becomes unusable, which requires maintenance, full or partial replacement. In any case, you first need to remove the carriage, establish the suitability of the part, and then decide whether to repair it or replace it with a new one.
The fact that the carriage has become buggy can be found only when you rotate the pedals. Visually, knot problems are difficult to identify, so it is best to prick up your ears and move your attention to the area of the bottom of the frame. You should not listen too much, especially if you are driving on a busy road. However, if the state of the carriage is not good, it will shout about itself without delay.
A faulty bottom bracket will prevent you from cycling quickly. Blocked dirt, worn bearings and lack of lubrication will continually impede movement. All this is accompanied by an unpleasant creak and a characteristic knock from below. Also, the unit may start to play (broken bearings and axle misalignment).
You can finally check whether it is really worth disassembling the carriage using the standing ride method. To do this, you need to accelerate a little, get up from the seat and twist the pedals. When the carriage mechanism is jammed, the sounds and deterioration of the pedal travel will only increase.
Troubleshooting: maintenance, cleaning, replacement
Dismantled the carriage, pulled it out of the frame and what do we see? The condition of the bottom bracket depends on how much dirt gets into it and how much the bearings are worn out. Sometimes the bearings simply shatter and require a complete replacement. This often happens if the carriage assembly has been in operation for more than three to five years.
First, all parts must be checked for defects. This primarily applies to bearings. Then we inspect the carriages, cups with latches. If any component has visible damage, then you need to change it to a new one. The rest of the parts are cleaned in a solvent. The most difficult thing will be to clean the bearings: dirt is very firmly adhered between the balls.
The space inside the carriage glass is cleaned with a rag. It is better to sprinkle fine dirt with a lubricating spray (WD-40, for example) and wipe the walls with a soft dry cloth.
Bicycle bottom bracket: what is it and why?
The carriage is a unit located in the middle of the frame, placed in a special cavity. a glass. Where to looking for? It’s simple: it is hidden where the cranks with pedals and stars are located. The main function of the bottom bracket is to connect the crankset to the frame of the bike and provide torque when pedaling.
A quite reasonable question may arise: what, without this device, you can not do at all? There is no bicycle without a carriage. If such a person is still caught, it means that he is not in use now.
Depending on the bike model, carriages differ in size and maintainability. The most common are 68mm knots, but other diameters can also be found. Carriage shaft length range: 110mm, 113mm and 122.5mm.
- cartridge (disposable);
- collapsible to be repaired.
The first type includes carriages that are installed in the frame and cannot be disassembled. Obviously, the service life of such a mechanism is equal to the time of complete wear of the bearings or axle. Full sealing of the unit allows you to operate it for a long time even in extreme conditions, not to mention measured driving.
Collapsible mechanisms will require periodic inspection and maintenance from the owner. The latter consists in replacing worn bearings and lubricating the entire assembly. We will just talk about them further: how to remove the carriage, eliminate the malfunction and reassemble the assembly.
Carriage Lubrication and Assembly
Using a screwdriver, the walls of the glass are processed. Apply the product in an even thin layer. No need to put grease inside the mountain. This is useless. Then grease is applied to the bearing, which is inserted from the side of the stars. The flat bezel should face outward. Then you need to lubricate the carriage shaft and insert it so that the long end is on the transmission side. In general, the carriage is assembled in the reverse order.
The bearing on the other side is inserted in reverse, with a frame into the glass. The cups are lubricated from the inside, and then put on. It is necessary to tighten until the axial play is completely eliminated. In this case, the rotation of the shaft should be slightly constrained. As soon as the fastening rings are mounted, the cup will move slightly and the axle will rotate freely.
It remains to collect the connecting rods. The most important thing here is to put them on so that when pedaling, God forbid, they do not fall off. Procedure for Effective Connecting Rod Assembly:
- The square is lubricated with a small amount of grease, this will help to push it deeper onto the axle.
- Processing a screw with a thread lock.
- Tighten the connecting rod nut with maximum effort until it stops. You can even lengthen the wrench. the thread will not break.
- Insert plugs.
A bicycle is an extremely unstable unit, therefore, during any repair work, it must be carefully fixed. The frame will not wiggle back and forth, which eliminates the risk of the bike falling to your feet or hands.
The carriage is assembled and ready for use. In general, the procedure is simple even for the first time, and in the future it will not be difficult to disassemble and install the mechanism at all.
What is a carriage
The bicycle pedals are attached to the cranks, which in turn are screwed into the carriage. The latter is a shaft placed in a special cavity of the frame. a glass. As you might guess, the element is located at the bottom of the bike. The main purpose of the carriage is to connect the connecting rods and their circular motion during pedaling.
Different carriages are installed on different bike models. They differ in the following parameters:
- The size. The most widespread are 68 mm knots. However, in a professional environment, you can find shaft lengths of 110 mm, 113 mm and 122.5 mm.
- Maintainability. Cartridge cartridges are not serviceable; if a squeak or backlash occurs, they are replaced with new ones. Dismountable serviceable: cleaning followed by application of fresh lubricant.
- Materials. Inexpensive carriages may have a plastic cup on one side, which is easy to break when disassembled. Below is a method for avoiding damage to a component while removing a part. Also, oil seals play an important role, which protect the bearings from moisture ingress: the better they are, the longer repairs will not be required.
We identify the malfunction
The features described below will also be relevant for the rear carriage of the bicycle, or rather the hub. The first signal of a problem will be a characteristic sound. A squeak occurs when there is insufficient lubrication, and a crunch occurs when dirt gets into the bearings.
Important! All signs are determined while driving, the breakage is not visible visually. The second signal will be difficult pedaling and knocking at the bottom of the bike. With a large reel, the development of a part is observed. In this case, there will be a backlash.
The final check is carried out while standing. It is necessary to pick up speed and step on the pedals, if the problem is present, then its symptoms will intensify.
What to do if you need to remove the carriage on a bicycle: detailed instructions
If cycling is carried out quite rarely, then a person may never be faced with the need to carry out the procedure described in the article. But the regular use of two-wheeled vehicles will sooner or later require appropriate maintenance. Below we will figure out how to remove the carriage from the bike, carry out its further analysis, cleaning and lubrication.
Removing the carriage from a bike
We will warn you right away, without a puller, the procedure is almost impossible to perform. If you try to remove it without a special tool, there is a high probability of breakage of the carriage cup.
- squeezing the connecting rod (if the connecting rod is removed without it, then a 14 mm head or an 8 mm hex wrench is required);
- small adjustable wrench or set of open-end wrenches;
- flat screwdriver;
- medium hammer;
- carriage remover for unscrewing the glass (depends on the carriage model, manufacturer).
Note! Additionally, an M8 bolt with a 1 mm pitch and spacer nuts may be required. It is necessary for a more reliable fixation of the puller and to prevent the splines from licking.
Before starting the procedure, it is recommended to wipe the bike from dirt, so it does not get into the threaded connections. At the end of the preparatory stage, you can proceed to the direct removal of the carriage. Step-by-step instruction:
- Remove the connecting rod from the sprocket side:
- Remove the bolted plastic plugs.
- Unscrew the fixing bolt using a squeeze or a 14 mm socket. An 8 mm hexagon is also used, depending on the model.
- Apply a squeeze to remove the connecting rod. It is screwed into the internal thread, then the nut is clamped, which moves the pusher.
- At this stage, the cup and the carriage itself will become visible. They start from the right side, since in some cases a plastic cup is installed on the left, which easily breaks when twisted. Such a nuisance will require a complete replacement of the carriage on the bicycle. You do not need to touch the left connecting rod. it will be removed by itself at the end of the process.
- Take a carriage puller and fit it to the cup slots. If the grip is poor, it is recommended to use an M8 bolt as follows:
- Put a few freely moving nuts and a washer on the bolt.
- Install the puller and fix it in the slots by screwing the bolt into the carriage.
Further disassembly, cleaning and lubrication of the moving elements of the carriage is carried out in the following sequence:
How To Remove Bike Crank Arms (Two Types!)
- The left ball cup was removed when the carriage was unscrewed. The right one remained pressed into the bushing. To dismantle it, it is necessary to screw the connecting rod bolt into the axle, then grasp the glass with one hand, and with the other, using a hammer, make several blows to the bolt head.
- Now access to the anthers covering the bearings has been gained. They are picked out with an ordinary flat-edged screwdriver. After you managed to remove the boot from the bike carriage, the bearings will become visible. If not, then the access is blocked by the separator. This part is installed if the bearing balls are not fastened together. She, too, can be removed with any sharp object.
This completes the carriage service. It remains to install it in the bike frame in the reverse order.