How to determine which chain on a bicycle

The main parameters of the bicycle chain

A bicycle chain is made up of links. In the English literature, the term link is used for this. English. Link. link, links. links.

Bicycle chain links are different. The standard distinguishes between inner link, outer link, connecting link (chain lock) see Fig. 1.

determine, which, chain, bicycle

Fig. 1. Outer link, inner link, connecting link

When to Replace a Chain on a Bicycle

Bicycle chain manufacturers rank them in terms of reliability, precision and durability.

Modern bicycle chains can be used equally well on various types of bicycles. A bike chain can be used on a city bike, road bike, touring bike, or mountain bike. However, some manufacturers clearly relate their bike chains to bike types.

The bike chain has been re-configured for smoother gear shifting. In some areas of the plates, the designers provide special chamfers. These chamfers facilitate the operation of the shifters by speeding up the secure engagement of the sprocket teeth and bike chain see Figure 2.

Chain wear depends on operating conditions and regular maintenance. Due to different operating conditions, identical chains from the same manufacturer installed on a mountain bike and a road bike will wear differently.

Let’s analyze the main parameters of the bicycle chain, which play an important role in the selection of a new chain.

Bicycle chain

A bicycle chain, front sprocket or system, rear sprocket or cassette form the bike’s drivetrain. A bicycle chain is made up of links. Many bicycle chain manufacturers supply their chains with a special detachable link. the chain lock.

The bike chain is subject to fairly intense wear and therefore can well be classified as a consumable. To extend the life of the drivetrain, cyclists practice using not one, but several chains, which are installed on a bicycle in a circular manner. Circular replacement usually requires 2-3 chains.

Bicycle chain pitch

As noted, bike chain pitch is 1/2 ”or 12.7mm.

Bicycle chain width or pin length

The overall width of the bike chain is determined by the pin size. The designers design the width of the bicycle chain based on the width of the cassette and the number of stars in it.

There is a clear trend towards a decrease in the width of bicycle chains with a simultaneous increase in the number of stars in the cassette.

Bicycle chain main dimensions

For mountain bike and bike hybrid

There are three main calculation methods when it comes to mountain bikes and bicycle hybrids.

  • Throw the chain over the largest sprockets in the back and front of the bike, pull the rear derailer leg to the maximum, you need it to move forward. this will be the ideal size for the bike chain. It should look like this: the derailer’s body will be practically on the same mowing line with the paw (this is the maximum, further. failure). Please note that it is recommended to install the foot at a slight slope.
  • As in the previous version, the chain is thrown onto the largest sprockets without involving the rear derailer. We write down or remember the required chain size, then add a couple more links to this parameter, and an acceptable length comes out. In principle, approximately the same as in the first method should come out.
  • Attach the chain in the front to the large sprocket and the smallest to the back and adjust the size so that the derailer’s foot is at right angles to the ground, that is, the derailer’s roller axes are under each other.

On a note! If you are the owner of a 2-outboard bike, then in this case it is necessary to measure the length of the chain with the shock absorber in a compressed state.

For singlespeed (single speed bike)

To choose the length of the bicycle chain for a single speed or a bicycle equipped with a planetary hub, it is necessary to install the latter in the suspension bracket of the frame (dropout) so that in the future, as the bicycle chain is stretched, it will be possible to move it back.

Attention! When replacing a factory chain with a new one, it is imperative to count the links in the factory sample. In the new chain, if necessary, it is necessary to leave the same number of them as the original.

Bicycle chain length: how to determine and choose the best?

Bicycle chain. links connected one by one with pins. It is intended to transmit torque. The efficiency is capable of reaching 98%. When installing a new chain on a bicycle, as a rule, it is necessary to correctly calculate its length or the number of links. A short chain can lead to problems if gear changes are made to large sprockets. Too long chain. will sag and jump off the sprockets on its own.

Basic sizing methods

There are two key tricks for determining a parameter such as chain length.

  • The most important thing is to install it on a large sprocket in the transmission system, at the same time it is necessary to install it on the smallest sprocket in the rear sprocket system (also known as the rear cassette). Then you need to pass it through the rear derailer (this is the name of the derailleur). After completing this work, tension it so that the axle that passes through the center of the rear derailleur rollers is in an upright position. If the correct chain tension has been performed and it turns out to be longer, a certain amount of extra links will form at the connection section of the 2 ends. They can be easily removed by adjusting the chain length at the same time to fit your own bike.
  • The next method actually mirrors the sequence of steps of the previous method. That is, mount the chain on the smallest sprocket of the transmission system and the same sprocket in the rear sprocket system. At the same time, there should be a slight tension on the chain, that is, the bike chain should not be loosened. It follows that unnecessary links may also remain in the junction area, which must be removed.

It should be further noted that in determining the optimal length of the bicycle chain, you can practice the first and second methods at the same time. If in both versions the same number of unnecessary links came out, then it means that you can safely remove them.

When the number is different, then it is worth checking again, since it may be that a mistake was made in some of the options. If you remove the wrong number of links, there is a risk of getting a chain that is too long or too short. In such situations, driving on two-wheeled vehicles is risky, and the degree of reliability of the bicycle chain will significantly decrease.

How to find out how many links are in a chain?

There are two methods to count the number of links.

  • Count all the outer links together with the lock, and then multiply by 2. It is possible, of course, to count the inner links, but this is not very logical.
  • Count all pins (their number must match the number of links).
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How to find out for different types of bicycles?

For road bike

For a road bike, the 3rd method is usually used for calculating the size of the bike chain. This is a technique where the chain is installed on a small sprocket in the back and a large one in front.

Method: the largest sprocket is the largest ring in the chain

An alternative method to measure the length of a new chain is to use the largest sprocket on your bike. This is the easiest way to measure a circuit without passing it through a switch. After determining the length of the chain, remove and cut it. Then run the circuit through the switch and connect.

  • Remove the old chain.
  • Place the front derailleur on the largest sprocket and the rear derailleur on the smallest.
  • Draw the chain through the front derailleur. In this case, there is no need to pull it through the back. Just wrap it around the largest front sprocket and around the largest rear sprocket.
  • Pull the chain and note the nearest rivet where the two links meet. Keep in mind that the chain can only be connected by crossing the inner and outer plates.
  • From the nearest rivet, count two links (equal to one inch), thus extending it. Cut the chain at this point.
  • Remove the chain from the bike, feed it through both derailleurs and connect the ends.
  • Pay attention to the main link: If there is a main link in the chain, then it is necessary to count from it along one side of the chain. Measure the chain and cut off excess links.

    Determining the chain length by mathematical calculation

    Bicycle chains are made up of inner and outer plates. The only possible way to connect them is to connect the outer plate to the inner one, so the chains can be connected if there are whole links. For example, some speed bike chains can be 51, 52, 53 inches long. Chain cannot be cut to lengths of 52-1 / 4 “, 53-1 / 8”, or even 52-1 / 2 “.

    It is possible to determine the length of the chain using the industrial railway equation, and cut it off before mounting it on the bike. Start by counting the number of teeth on the largest front and back sprockets. This information is often written directly on them. The next step is to measure the distance between the center of the crank bolt to the rear axle. This will be the chain length in multiples of 1/8 “and convert to decimal. The table below will help you with this.

    For most bicycles, a relatively simple chain length equation can be used. For bicycles with a larger sprocket difference and a shorter chain, a more complex equation can be used. It is described further in the article.

    Simple equation: L = 2 (C) (F / 4 R / 4 1)

    How to Size a Bicycle Chain

    L = Chain length in inches. Rounded whole number. C = Distances from the center of the crank bolt to the rear axle in inches, a multiple of 1/8 “. Use the decimal to decimal conversion table above. F = Number of teeth on the largest chainring. R = Number of sprockets on the largest rear sprocket asterisk.

    Example: Your bike has front sprockets 42-32-22. Sprocket 42 is needed for the calculation. The largest rear sprocket installed has 32 teeth. The distance between the center of the crank bolt to the rear axle is 16-3 / 8 “, which equals 16.375 inches. L = 2 (16.375) (42/4 32/4 1)

    The above example gives the following equation 32.75 10.5 8 1 = 52.25 inches. Chains cannot be joined at 52.25 inches, so the number is rounded to 52 inches.

    According to this system, the number can be rounded up to 0.5. For example, a calculated chain length of 55.5 should be rounded to 56 inches.

    To measure a new chain, lay it on a flat surface with the rollers and plates vertically. Pull on both ends to align the chain. Measure it starting at either end. Remember, you can only shorten the chain by a multiple of one inch. If a main link is marked on the chain, use it as the starting point for the measurement.

    Method of using existing circuit

    Before removing the old chain, check how much chain you need. Cut a new chain equal in length to the old one. Shift the bike speed so that the chain is on the smallest front sprocket and the smallest rear sprocket. Take a close look at the area of ​​the chain between the lower derailleur and the smallest sprocket. There should be no noticeable slack in the chain at this point. Also check that the bottom of the chain does not touch the pulley. It is okay if there is a little slack in this position of the chain, but it should not bend too much. Too much slack is an indicator that the chain is too long.

    If the chain is too long, find the rivet that touches the sprocket and mark the sprocket there. Count two rivets towards the derailleur, lift the link up and slide it to the mark on the sprocket. The chain is now much shorter. Check the slack again. Repeat this step by counting the two rivets and sliding the chain up to the mark. The number of chain links to be cut should be (2, 4, 6, etc.). Repeat until there is no visible sagging.

    To determine if the chain is too short, move it to the largest sprocket in the front and the second largest sprocket to the rear. The chain will stretch in this position. Look closely at the S-shaped section of the chain, as this is where it goes through the pulley. Slowly and gently begin to rotate the largest sprocket at the back. If the chain is too tight, it is too short. If the chain moves, but it turns out that there is no double bend, when the chain passes the pulley wheels, it is again too short. You need to add two links to the new chain, compared to the old one. Caution: do not try to lengthen the old chain by adding new links.

    If the chain length passes one of the tests listed above, but fails the other, then it is most likely that the derailleur capability does not match the gear. Determine the length of the chain so that it runs through the large chainring to the largest rear sprocket. After that, all responsibility for shifting the combinations when changing gears will lie with the owner of the bike.

    If you want to install a new chain instead of the old one. the correct length, you can measure the new chain to the length of the old one before installing. First remove the old chain and place it on a flat, flat surface with the rollers vertically. Align the chain. Place the new chain next to the old one in the same way. Check that the ends of the two chains match (either both chains must have rivets at one end, or both chains must not be riveted). The new chain will appear shorter, so slide the links of the old chain so that they line up with the new chain. Install matching rivets on the new chain, with rivets on the old one. Add or remove links as needed based on the checks above and cut the chain at this point.

    What tools are needed?

    Derailleur bike chains must be of a certain length. A chain that is too long or too short can cause problems when shifting and driving. However, the foot of the rear derailleur should be long enough to pull up the weakened chain as it moves between different gear combinations. All of this belongs to the topic “Total Power” and is discussed below.

    This article describes three ways in which you can find the correct chain length. All three ways can achieve this. In addition, there is no need to use all three methods, it is enough to choose one that suits you and suits the situation. The first method can be described as USING AN ALREADY EXISTING CIRCUIT. It assumes that the bike is already equipped with a chain. The second method is called: THE LARGEST STAR IS THE LARGEST RING OF THE CHAIN, and it does not imply the presence of the old chain. The last method is a METHOD FOR MATHEMATICAL CALCULATION OF THE CHAIN ​​LENGTH.

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    REAR SUSPENSION REMINDER: If your bike has rear suspension linkage, you need to calculate the movement of the rear hub from the bottom bracket. If the rear hub moves away from the carriage, then the chain is in the longest position. If in doubt, consult the manufacturer for the correct chain length.

    SWITCH CAPACITY: The term “Switch Capacity” refers to its ability to raise the foot when shifting gears. Some bicycles have sprocket combinations that prevent the derailleur from raising the chain foot. In this case, the gears on the bike exceed the capacity of the derailleur. If the capacity of the derailleur does not match the size of the bike gear, the chain will not pass the too long or too short test. It is impossible to choose a chain length that would satisfy both parameters. In this case, it is better to keep the chain longer than shorter. Both methods, the method using an existing circuit and the method of mathematical calculation described below, will determine the safe length of the circuit if the capacitance of the switch is broken. Perhaps, in this case, it is worth avoiding those speed combinations that lead to problems when moving around on a bike.

    How to choose the length of the bike chain?

    In this article, we will discuss how to find the correct chain length for a shifter bike.

    Strict equation

    An example of a bike that requires an exact equation would be road bikes with large chainrings (possibly 55 teeth) and small rear sprockets (11 teeth). In addition, if the bike has a very short distance from the center of the crank bolt to the rear axle (15 inches or less), then again a strict equation will need to be applied. Since the front and rear sprockets are different in size, then the chain should diverge, representing a triangle. The chain length of the resulting triangle can be added by using the hypotenuse. Again, this applies in very exceptional cases. As an example of applying the strict equation, suppose the chain length of a single speed bike is 15 inches, the front sprocket has 58 teeth, and the rear sprocket is 11. The bike does not have a derailleur, so the length does not need to be increased by 1 inch. This inch should only be added on shifter bikes.

    Calculating the length of the road bike chain using the shortened equation gives the answer 47.25 inches. Round this result to 47 inches. Using a strict equation, the result is 48.17 inches, which is rounded to 48 inches. Again, in the example shown, an inch of chain is not added, since there is no gear selector. Calculated using the simplified equation, the chain will be one inch shorter. But this is not a typical situation. Usually, even in the single speed bike example, if the sprocket is reduced to 55 teeth, the two equations will produce the same result.

    Determining the required length

    Before you understand how to properly shorten the chain on a bicycle, you need to find out how long it should be for normal movement. To determine this, the chain must be thrown over large stars in the rear and front undercarriage.

    Then you need to open one link. At the end, you need to tighten the chain as much as possible. A few centimeters must be added to this length so that there is no overvoltage. This will be the optimal length.

    What are the chains?

    To understand the principles of work, you need to know the types of bike chains and their features. All bicycles now use single-row roller targets with a pitch of 12.7 m.Each link has outer and inner plates, saws, rollers and rollers.

    The number of speeds changes the width of the product. If there are many sprockets, then the chain is narrow. Products are distinguished by the presence and absence of a lock, which serves for convenient dismantling and installation of the chain.

    What affects chain elongation?

    The wear of the chain pins (pins) is due to a number of factors. This is due to the accumulation of old oil between the structural parts, which attracts dust and debris. Elongation occurs when the chain is overloaded when driving up steep inclines.

    A common cause of target sagging is at the end of its useful life. The product deteriorates from impacts, metal corrosion. To eliminate the inconvenience of driving, you need to know how to shorten the chain on your bike. After that, the vehicle is again suitable for a comfortable ride.

    Squeeze shortening

    How to shorten a bicycle chain using a squeeze? To do this work using a special tool, you must go through the following steps:

    • Place the squeeze so that its core is in the center of the link axis.
    • Rotate the tool so that the axis goes out of the link.
    • Disconnect the circuit, then do the same procedures with other sections.
    • Eliminate unnecessary links and fasten the structure.

    Once you understand how to shorten a chain on a bicycle, you need to figure out how it can be connected. A narrow half-link is inserted between the wide cheeks. Then the axle enters the bore of the bushing. Then you need to check the mobility of the links. If it is of poor quality at the joint, the hinge should be developed with pliers.


    When there is no squeeze, you can use the tools at hand. All you need is a hammer and a metal rod, which will be a punch to eliminate the link axes. Nuts are also required and must be placed under the links.

    How to shorten a chain on a bicycle: features of the procedure

    Cycling is largely done with a chain. Over time, it sags, which makes the trip more difficult. This raises the question: how to shorten the chain on a bicycle? This procedure can be performed independently, if you apply simple practical advice.

    Getting ready for work

    To make it easier to work with the chain, you need to clean it. This requires a small cloth to remove debris and dust. Only the material must be pretreated with kerosene. A special wash is also used, for example, liquid AB-80 or WD-40.

    Single speed bike chain length

    To determine the chain length for a single-speed bicycle or a bicycle with a planetary hub, it is enough to install the hub in the frame dropouts so that it can be further pushed back as the chain stretches.

    I installed my planetary hub almost at the beginning of the dropout so I could move it back.

    Road bike chain length

    For road bikes, there are usually 3 ways to determine chain length. This is a method in which the chain is placed on a large chainring and a small rear.

    How long should the bike chain be?

    I think many who change chains on their own bike ask themselves the question: “What should be the correct chain length?”, Since new chains come with a margin in length. And, of course, the simplest thing we can do is count the number of links on the old chain and leave the same number on the new one.

    But what if you are not only installing a new chain, but also changing the cassette or installing a system with a different number of stars? The chain length will change, and the old chain is no longer a helper. Then you should use these 3 methods to calculate the length of the bicycle chain, and no calculator is required for this:

    Mountain & Hybrid Chain Length

    1 way. Place the chain on the largest chainrings on your bike (large front and large rear), pull the rear derailleur foot as far as possible to move it forward. this is your optimal chain length. You should get it so that the body of the switch lies almost on the same straight line with the foot (this is the limit, further. breakage). It will be correct to set the foot at a slight angle, as in

    If you make a mistake and make the chain shorter than necessary, then in the case of an accidental inclusion of the two largest stars in the system, the length will not be enough, and the switch will tear off to hell.

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    Method 2. The same as the first method, only we throw the chain onto the largest sprockets without using the rear derailleur and remember the desired chain length, after which we add 2 more links to this length and get the ideal length. In theory, you should get about the same as in the method

    Shimano Bicycle Chain Length Determination Method

    A chain link is a chain element, a distance that is limited by two pins (axes) of the chain.

    Method 3. Place the chain on the smallest sprocket at the back and the largest at the front, and adjust the chain length so that the derailleur foot is perpendicular to the ground, i.e. the roller axles of the switch were under each other.

    With the red line, I showed the perpendicularity of the switch rollers relative to the ground.

    Attention! If you have a double suspension, then it is necessary to measure the length of the chain in this position of the rear shock absorber, when the driven stars are as far as possible from the carriage (when the shock absorber is compressed).

    Checking if the bike chain is too long

    After you have chosen the chain length as described above, I recommend that you test the chain operation when using the two smallest chainrings at the front and back. If the foot is almost parallel to the ground, your chain is too long. It will likely jump off bumps frequently (as the switch will not be able to pull it properly). The foot should be at a slight angle. See the photo below for more details:

    As you can see in the photo, the foot is set at an angle. This means the chain is tensioned by the derailleur and is the correct length.

    The recommended distance from the top roller to the chain is 2.5 to 4.5 cm.In this case, the derailleur will work correctly.

    I got about 2.5 here, since this bike has a very large 1 star on the cassette.

    Bicycle drive | How to Determine Drive Wear on a Bicycle

    Bicycle drive | How to determine wear on a bike drive

    A bicycle drive is a collection of interconnected elements / parts that transfer energy from the cyclist’s feet to the drive wheel.

    The most commonly used chain transmission, in which mechanical energy is transmitted using a chain. a flexible part of the bicycle drive. The chain clings to the teeth of the system (chainrings) and cassettes / ratchets (rear sprockets) thereby ensuring the transfer of energy.

    The chain drive has many advantages:

    1) High efficiency (the transmitted energy is practically not lost);

    4) Work with many high-speed transmissions;

    3) Jerks are possible when working on small stars, since the speed is not constant.

    There is also a belt drive, but it is extremely rare.

    How to Determine Drive Wear on a Bicycle?

    All drive elements tend to wear out, the chain is most susceptible to wear, but let’s look at all the drive elements.

    Chainring / system (chainring).

    Depending on the level of equipment and the riding style of the rider, the service life of the system is 15,000. 25,000 km. If your chain starts to slip, this is the first sign of wear. Look at the back of the teeth to determine the level of wear. The new system has teeth of the same size and shape, the back side is “steeper” than the front.

    Rear sprocket / ratchet (cassette).

    Rear sprocket life also depends on equipment level and riding style. On average, from 10,000 to 15,000 km. Wear is determined in the same way as on the system, by teeth.

    You can determine chain wear using special tools or a ruler. If you attach a stretched chain to a new one (with the same number of links), the old chain will be several links longer. The resource of the chain also depends on the level of the equipment, but not more than 4000 km, however we recommend changing the chain every 1500.2000 km. A badly worn chain due to the mismatch of the links with the teeth will quickly wear out the system and the ratchet (cassette).

    The easiest way to determine chain wear is to use a ruler, the chain does not need to be removed from the bike. One link of the new chain is 12.7 mm. For a more accurate measurement, it is better to measure the length of 24 links, from the center of the first axis to the center of the twenty-fifth. The new chain will have a size of 304.8 mm, It is allowed to stretch up to 306.4 mm, in such cases only the chain will have to be replaced, if the stretch is more than 307.9 then the system and the cassette (ratchet) will have to be changed, otherwise the chain will slip.

    Based on the above, it should be remembered that if you have a lot of wear on the bike drive, then it is better to change all the components at once (system, cassette, chain) because replacing individual components can lead to unpleasant chain slippage and faster wear on good components.

    If you do not know how to check chain wear and replace faulty components, please contact our bicycle workshop.

    Learning how to fix everything yourself

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    My VK Useful videos from my channel about bike repair. 1) Rear wheel hub service. 2) Front wheel hub service. 3) How to fix, align the figure eight on the bike wheel 4) Brakes v brake setting how to adjust and install on the bike 5) Solid oil and lithol 24 can be lubricated or not. 6) KT-305 how the hub with a foot brake works, maintenance, mechanism design. 7) Backlash and shake, the rear or front wheel spins, how to fix it. 8) Replacing and adjusting the rear crossover 9) Adjusting the front crossover of the bike / watch? v = bKvnDcujDRg 10) How to soften the fork on a bike. 11) sr suntour XCT fork restoration and repair 12) Repair of a simple spring bike fork https: // 13) Replacing the bottom bracket on a bicycle, how to remove the cranks, how to remove the bottom bracket, how to disassemble the bottom bracket. 14) Bicycle rear sprocket ratchet, how to disassemble the ratchet. 15) Chain length, how to determine the chain length, remove and tension the chain on the bike. 16) How to disconnect, rivet, bicycle chain. 17) How to use a squeeze for a bicycle chain, a secret. 18) How and how to paint a bicycle frame made of aluminum or stainless steel at home. 19) Replacing the bike front fork 20) Squeaking, crunching and knocking on the pedals and bicycle bottom bracket how to fix. 21) How to disassemble and assemble the bottom bracket on a bicycle, replacing bearings. 22) Repair, disassemble bicycle pedals. Installing how to remove the pedals from the bike. 23) How to calculate bicycle spoke length, spoke calculator. 24) How to latch, replace, spokes on a 36-spoke bicycle wheel. 25) How to replace or install brake pads on bicycle disc brakes. 26) Shimano Tourney rear crossover repair, restoration. 27) Rear Shifter Shimano sis. repair, restoration. 28) How to learn how to ride a bike independently for an adult and a child. 29) BOLI and FLAME disc brakes, installation, tuning and adjustment. 30) Backlash, swing of the rear ratchet sprocket on the bike, how to clean it, what is the reason. 31) How to glue, glue the bicycle camera correctly, 1 bar = 0.986 atm

    thoughts on “The length of the chain, how to determine the length of the chain, remove and tighten the chain on the bike.

    Not really detailed. But I put it like it. Of particular interest is the device that shortens the chain. no detailed overview. minus you.

    Very useful videos about bike repair. Well told and shown! Thank you very much! Be healthy and keep up the good work!

    modern chains are not very durable, even the campagnola was blown away))