How to Assemble a Bottom Bracket on a Pedal Bike

The carriage in a bicycle, what is it, what is it for

Let’s analyze this device together. This information will help you figure out how and what needs to be repaired in your bike.

So, in the middle of the bike frame is the bottom bracket assembly. It is located in a container specially assembled for it. It’s called a glass. Look for cranks, pedals and sprockets nearby to accurately locate the bottom bracket.

The main purpose of this assembly on your bike is to attach the cranks to the frame of the bike, and provide torque as you depress the pedals. So without a working carriage, there will be no working bike.

This device differs in size according to the bike model. There are also differences in the repairability. The most popular carriage units at this time are devices with a diameter of 68 mm. But this size can range from 110 mm to 122.5 mm.

Bicycle carriage assemblies are of the following types:

assemble, bottom, bracket, pedal

How To Install a Square Taper Bottom Bracket

  • once used like a cartridge;
  • those that can be disassembled and repair and replace bearings.

How To Remove And Install External Bearing Bottom Brackets By Performance Bicycle

The carriage, which cannot be disassembled, is installed in the bike frame. It serves until the bearings or the axle that make up it is completely unusable. Since such a unit is completely sealed, the operation of the device is possible for a long time, not only when you move measuredly and calmly, but also in extreme conditions.

A device that can be disassembled requires service. It is not necessary to contact a professional repair shop. I will tell you how to repair the carriage on a bicycle, how to replace a faulty carriage bearing on your own, without spending extra money on service.

You just need to replace faulty bearings and thoroughly lubricate the entire bike bottom bracket with grease.


Enter the mark or size (for example: 8227) of the product and the country of sale

Bug fixing, service, node cleaning

Once you have taken out the carriage, you can carefully inspect it for damage. If too much dirt and dust gets into the carriage assembly, the bearings become completely unusable and need to be replaced. This usually occurs after 5 years of use.

Carefully inspect all the parts in this unit. The carriage bearings are the first to break and break. Replace them with new parts.

At the same time, take a closer look at the condition of the clips with cups. If you see visual damage, also change these parts. Clean all other parts of the bike bottom bracket with solvent. The finest dirt is better removed with a special lubricating spray. At the end, wipe everything off with a napkin.

How to determine a malfunction

You will be able to find out about malfunctions in the mechanism of the bicycle carriage only when you rotate the pedals. It is quite difficult to visually verify the problem. You have to listen and pay attention to the sounds that the lower part of the frame makes. However, if all is not entirely bad, you will not hear anything. In case of heavy wear of the carriage bearing, you cannot go wrong by hearing the characteristic sounds.

With a broken carriage mechanism, you will not be able to move quickly. In this you will be hindered by dirt and dust, which are clogged in all parts, as well as a lack of lubricants.

With all this, there is an unpleasant, annoying squeak and knock at the bottom of your bike. You may also find backlash that occurs due to broken, worn bearings or axle misalignment.

READ  How to properly assemble the rear bottom bracket on a bicycle

To fully and fully make sure that you need carriage parsing, try another method. There is such a concept in cycling as standing riding.

You should do a little acceleration, while standing up and at the same time spin the bicycle pedals. If, at the same time, noises and unpleasant sounds intensify, it means that the carriage is jammed, and it is necessary to disassemble it for repair.

How to replace and repair a bearing in a bicycle bottom bracket?

Absolutely all mechanisms wear out after a certain time, as they are subject to external environmental factors. They require service, repair, or complete replacement with a new part.

To make sure what actions need to be taken, you will definitely have to remove the bike carriage, figure out which parts have become unusable, and then make a decision: make repairs or make a complete replacement.

We remove the carriage according to all the rules

To eliminate the detected malfunction, logically, you need to disconnect the broken unit from the bicycle frame. specifically, you need to get it out of a part called a glass. Let’s see how to do it yourself, without the help of specialists.

First, you need to decide what tools we need, and, accordingly, stock up on those.

The set of tools required for the process of removing the device from the bike frame:

  • use the connecting rod squeeze;
  • several wrenches. It will be very convenient to use an adjustable wrench if you do not know the size of the nuts;
  • flat screwdriver;
  • small hammer;
  • to remove the carriage from the glass, you need a special puller.

Before disassembling the mechanism, clean everything around the work area. Use a damp cloth to wipe off any dirt on the frame, on the connecting rods, and on the bottom bracket. It will be more convenient to repair if you wash the entire bike completely.

First of all, the connecting rods are freed from the plugs. Plugs are plastic covers. You just need to pry them off with a screwdriver and remove them. It is completely easy and simple to put them back.

The connecting rods are attached to the carriage with mounting nuts. They need to be unscrewed. At this stage, the use of pomace will come in handy by the way. The squeeze is put on top of the nut, and unscrewed with a wrench.

Pay attention to what type of thread. The direction in which you loosen or tighten the nut depends on it. There are different options. The right-hand thread can be on the left side (the tightening force decreases counterclockwise). Left-hand thread on the right-hand side, increase the tightening torque counterclockwise. There is only one thread to the right on both sides. You will see everything for yourself.

Next, remove the connecting rods. Insert the squeeze into each of them with the opposite end, and twist it inward. In order for the bolt to come off the axle, it is necessary to tighten it strongly in the middle of the connecting rod. Slowly it will start to move, and you can take it off. It is advisable to shoot where there are no transmission stars.

There are such special cups held by rings. The bicycle carriage rests on them. Place a screwdriver on the left. By lightly tapping it with a hammer, you will make the small ring turn to the left and pop off. Also, turning to the left, with a blow, you will get the cup.

In the end, we found worn out bike bottom bracket bearings. Using the same screwdriver, prying the bearings, you will get them.

How To Remove/Install Sealed Cartridge Bottom Bracket

Using a removable device, remove the carriage shaft from the glass. This part, which rotates, performs the main function of the movement of bicycle cranks.

How to replace a bottom bracket bearing on a bicycle yourself

After reading the article below, you will learn how to repair your bike bottom bracket by replacing the bearing.

All bicycle enthusiasts as well as cyclists are familiar with the term carriage mechanism. This device is under the greatest stress.

assemble, bottom, bracket, pedal

Ball bearing carriage lubrication

It should be noted that carriages of this type are short-lived, therefore maintenance and adjustment of bearings should be carried out quite often.

READ  How to bleed the brakes on a Honda Lead scooter

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 areas on a bike and is usually difficult to clean until the cranks are removed. Especially carefully it is necessary to scrape out the dirt from the slots of the cups. if there is a lot of dirt, then it is impossible to insert a stripper into the cup.

Removing the carriage may require considerable force. 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. with a key (if it is not there, then you can also use an ordinary family member). This nut has a right hand thread. It may be necessary to apply considerable force when unscrewing. It is necessary to unscrew 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 photos show the slotted one.) Insert it into the slots, 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)

Move 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 grease 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 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 connecting rods and the system.

Fault definition

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.

READ  How To Find Out The Size Of The Bottom Bracket On A Bicycle

Removing the carriage from the bike

Next, we will consider the process of removing the carriages using the example of a Shimano open bottom bracket.

When removing the carriage, you need to be careful, since it can be with loose bearings, which, when removed, can fly apart in different directions.

To remove the connecting rods from the carriage axis, you need a tool such as a connecting rod squeeze. This tool has two functions: its right side is intended directly for squeezing the connecting rod from the carriage axle, and the connecting rod fixing bolt is removed through the left side.

First, using a pedal wrench, unscrew the connecting rod tightening bolts located at the end of the carriage shaft. Plastic plugs (if present) can be easily removed from the bolts using a standard flat-blade screwdriver.

After removing the fixing bolts, proceed to the connecting rods. We take the squeeze of the connecting rods and screw the puller with the threaded part into the connecting rod until it stops. It is very important not to overdo it with pressure, so as not to disrupt the thread. Having successfully removed the connecting rods from the carriage axis, do not forget to wipe the seats.

Then, using a special puller, we remove the carriage itself.

It is important to know that the carriage is removed only from the side where there are no stars on the connecting rod, that is, on the left.

So, we insert the puller into the carriage slots on the left side and twist it with a handle or an adjustable wrench counterclockwise. In the process, you need to ensure that there are no distortions of the puller. Otherwise, he or the bowl itself may be damaged.

After the carriage bowl is unscrewed, you need to perform the same actions on the right side. Only in this case you need to turn the handle clockwise! As a result of such simple actions, the carriage will be removed and ready for service or replacement.

Want to see how to remove the crankset and bottom bracket? Watch the video review:

Carriage difference

How to remove the bottom bracket on a high-speed bike 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.

Maintenance of bicycle carriages

After removing the carriage, check the condition of the carriage glass for contamination.

Eccentric carriage

Allows the use of a drive without external gear shifting (singlespeed, planetary hub) in combination with conventional vertical frame dropouts. These dropouts provide a faster and more comfortable wheel positioning compared to horizontal ones. The eccentric carriage rotates 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 a BSA thread for a standard BB, requires a special frame with a 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 a 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.

On it is described in great detail about the repair of carriages and how and how they can be removed. Let’s figure it out with this issue too.