If you have a specific tool to open the links of a chain, called a chain cutter, you can easily repair the one on the bicycle. You can perform most maintenance work yourself, but be aware that once repaired, you should replace the broken chain as soon as possible.
Steps
Method 1 of 2: Without a Spare Shirt
Step 1. Take a picture, draw a sketch or memorize how the chain is assembled
Make a note of how it enters and exits the various pulleys, if any. The chain wraps around a derailleur (the mechanism that changes the rear gear ratio of the bike) following a precise pattern, not difficult to understand, which you must maintain later. Some models are simply threaded onto the sprocket.
If you proceed with care, you don't even have to take it off the bike; however, depending on which link is broken, it is likely to slip off during repair or cleaning. Take a picture right away before getting into it
Step 2. Set the front and rear gears to be on the center sprocket, but pay attention to which gear was selected previously
The broken chain does not move, but in this way the mechanisms are arranged in such a position that it is easier to reassemble it later; when the gear selected is "extreme", the weakened chain is more likely to break again.
If the bike only has one set of gears, you need a new jersey for repair. The method described in this article shortens the chain by one link, which means it cannot fit all relationships
Step 3. Remove the broken chain and clean it with a degreaser and water
Use an old toothbrush to remove dirt, rust and dust from the gaps in each jersey. When the chain is dirty, it is subjected to greater tension and is more susceptible to breakage; wash it so that the links can move freely in your hands, paying particular attention to those that appear "stuck" or that flow slowly. This simple precaution prevents it from breaking again within a short time.
If it looks stiff and rusty even after cleaning, you probably need to replace it; when it is in poor condition it could damage the gears and the front derailleur in the long run
Step 4. Use the chain tool to push a pin and half of it protrudes from the broken link
Although it looks like a medieval torture tool, this tool is actually easy to use. Each link is equipped with two pins that join it to the adjacent links; locate the damaged one and take note of the pin that keeps it attached to the rest of the chain. Slowly rotate the chain tool so that its strut pushes the pin out about half the length; do not pull it out completely.
If you have a spare pin (often included with the chain cutter), you can use it safely, as it is very likely to be stronger and safer than the old one
Step 5. Pull the broken shirt off the pin and discard it
Make sure that the pin does not come off the rest of the chain, you just have to eliminate the damaged piece; then you have to connect the adjacent open link to this element to close the chain again.
Step 6. Mount the chain on the bicycle respecting the original arrangement
Before connecting the open mesh, you need to proceed with this step; slide it through the pulleys following the pattern you photographed earlier. The order to be respected is generally quite intuitive, since there are metal elements that fix the chain to the sprockets; simply slide it between these elements and around the pulleys.
Turn the chain so that the partially protruding pin is facing you and not the wheel to make it easier to push it back to its original position
Step 7. Snap the two ends of the chain together to align the holes
The link with the pin should remain on the outside, to allow the bar to go through all four holes (two per link) and close the chain.
Step 8. Use the chain tool in reverse to push the pin into place
Previously you screwed the knob of the tool to push the pin outwards, now you have to do the same operation, but to fit the bar in its place; proceed slowly, holding the links in place with your hand to keep them aligned.
Step 9. Grab the chain on each side of the new joint and move it from side to side to "untie" it
It is worth moving the chain tool to the other side of the links you have just joined and push the pin slightly to free the two outer plates from the central section, preventing them from getting stuck together.
Step 10. Lubricate the chain with bicycle grease
Do not use WD-40 or products that are not specific. Turn the bike over and rotate the pedals with one hand while dropping the lubricant onto the chain with the other; 10-15 drops should be enough. Then use a wet rag and pat to remove excess grease. When you run a finger on the chain you should feel it a bit slippery but not caked with grease.
Step 11. Avoid using the larger rear sprocket, as the chain is now shorter than one link
In most cases you will not even be able to set this ratio because the chain is not long enough to reach it; however, the pull exerted by the attempt alone could break the element again if you do not proceed with caution.
- Keep the chain straight between the front and rear gears. Prevents it from running diagonally by simultaneously selecting the gear on the far right of the front sprocket set and the one on the far left of the rear group.
- This repair is temporary and you should get a new link or chain as soon as possible.
Method 2 of 2: Add a Mesh
Step 1. Add a new link as soon as possible to return the chain to its normal length
If it is broken, you can remove the damaged link and re-connect the two ends for a temporary repair. However, a shorter chain will not be able to rotate around all the sprockets, limiting the ratios available to you. You can buy replacement jerseys at any bike shop or at many sporting goods outlets.
There false mesh, also known as "quick release", is built to be mounted easily and anywhere; it installs quickly and is a good solution to always keep in the bag under the saddle during long rides. It is the most used jersey by amateur mechanics.
Step 2. Turn the mesh in the correct direction
Most of these are equipped with an arrow that indicates the direction of movement of the chain while pedaling. Those that do not have this detail are concave on the side that must face the wheel and the rest of the bike.
Step 3. Squeeze the two links together to unhook the two halves of the matching link
You can notice that the space for the pins of this element has an "8" shape instead of the classic hole present in all the other links; if you haven't already opened the chain, do it now.
Some dummy links have two asymmetrical halves, both "C" shaped pins and an outer plate. To repair this type of chain, slide the "C" shaped pin into both open holes and then snap the plate over it
Step 4. Take each half and push towards each other at opposite ends of the chain
Each pin of the false link must fit into one end of the chain; also check that the pins enter from opposite sides of the chain itself, which must then be closed using an "8" -shaped hole - the pins must therefore be aligned.
Step 5. Bring the chain and link together with the pins exposed through the "8" holes of the opposite links
You shouldn't have any difficulty in doing this; however you should be aware that the joint is very loose.
Some mechanics use a chain tensioner, a simple wire molded in the shape of a "C" that slides into the notches of the chain itself to keep it taut as they install the links. While not essential, this accessory or a helper that keeps the ends of the chain taut as you work can make the process a lot easier
Step 6. Use a pair of pliers to close the link by engaging the pins in their seat
You need to force them so that they fit into the other side of the "8" hole and close the joint. If you don't have a pair of pliers on hand, there are a few tricks to complete this step. Turn the bike over so that the saddle is facing down and slowly spin the pedals as you apply the rear brake; as soon as the brake blocks the wheel and therefore the chain, the tension exerted by the pedal should tighten the false link.
Step 7. Be aware, however, that a broken chain indicates that it must be replaced with a new one
Although repairs can be made in various ways (such as those described in this article), it is a good idea to buy a replacement. In addition to breaking, the old chains stretch as the pins wear out; it might seem like an insignificant detail, in theory, but it has a big impact on pedaling. The chain manages and transfers the force you exert towards the wheels; if it is slack, you have to try harder to reach a much lower speed.
Advice
- The chain tool is a tool worth buying. Sometimes the chain breaks for no apparent reason; so keep this tool handy every time you go out for a ride, as it could also be useful to help another cyclist in difficulty.
- Always keep the old chain and links left over from the new one as spare parts. However, remember that there are several models made to fit specific sprockets and that they are not always interchangeable.
- The chain pins are specific to the number of sprocket changes; if you have any doubts about it, ask the bike shop assistant.
Warnings
- Follow these instructions to the letter; do not be in a hurry in any step.
- If you are really in trouble, ask a professional for help.
- You should replace the pin you pull out with a new one; by reusing the old one you run the risk of it breaking. You can buy parts at a bicycle shop.
