Sometime in the near future, any avid cyclist will have the chain on their bicycle come loose.If you know what you're doing, you don't need to take your bike to an expensive repair shop.
Step 1: Find the slippage.
The chain will sometimes slip off of its intended path, but not break.Because, in this case, the chain is still routed through both the front and rear derailleurs, no special maintenance is needed.Get off the bike and look for slippage.The chain stays through both of the derailleurs when it falls off.If the chain is jammed against the frame, the bike can't be ridden again.
Step 2: If the chain is jammed use the quick release.
In the event of a slippage, the chain can get jammed between the frame and the rear sprocket.It's a good idea to remove the wheel nut from the chain and loosen the quick release on the rear wheel.Pull the chain out when you loosened the rear wheel.Pull the small lever at the center of the rear wheel to open the quick release.Remove the wheel nut from the other side to loosen the hold on the frame.The chain should come out easily once loosened.Re-tighten the quick release before you ride away.You should be able to close it completely, but not push it all the way down.Try to loosen the wheel nut if it feels tight.If it's too loose, tighten the wheel nut.
Step 3: If your bike has a rear derailleur, loosen the chain.
If you want to thread the chain around the front sprocket, slacken it.The rear derailleur on most bikes is spring loaded to keep the chain tight.Push the arm of the rear derailleur forward to introduce slack in the chain.This slack can be used to thread around the smallest of the front sprockets.Ensure the chain is tight by releasing the arm of the rear derailleur.You can ride away from here.The slippage may cause your bike to shift erratically until it shifts into gear.
Step 4: You can turn the pedals on a bike.
You can catch the chain on the sprocket by pedaling.Many bikes don't have derailleurs.The easiest way to fix a loose chain is to hook the chain onto the rear sprocket and then turn the pedal backwards.The chain should catch and turn around.The chain should start running through the bike's gears when the "caught" portion gets to the top of the front sprocket.It is easier to turn the pedals if the bike's rear wheel is raised.You can either put the bike on a stand or prop up the rear of the frame with any materials on hand.As you put the chain back on or turn the bike upside down, you can get a helpers to hold the rear wheel off the ground.
Step 5: The bike is in the right gear when you pedal forward.
You should get on your bike at a slow pace.Your chain may "jump" back into the gear it was in when the slippage occurred if your bike has gears.Until the chain pedals smoothly, keep changing gear.On fixed-gear bikes, chain slippage can be particularly dangerous and problematic and is often the symptom of a chain that's too loose.You can adjust the tension in your chain by sliding the wheel back and forth.
Step 6: There are some final checks to be done.
Before you start riding again, make sure you are comfortable.If your bike has them, you can change your gears on both the rear and front derailleurs.
Step 7: A new chain and tool is required.
To replace a broken or fallen off bike chain, you will need a new chain that fits your bike and a chain tool to remove the old chain.The new bike chain should come with a replacement pin.You can buy these items at a sporting goods store.
Step 8: If possible, attempt a repair.
Put your bike on its side with the sprocket up.Look for the break in your chain if the chain is still on the bike.If the chain is hanging from the sprocket, it should be easy to find the separated ends.The new chain can be put on if the chain has fallen off completely.Each link is connected to the next by passing a metal pin through the outer and inner parts of the link.Chains with special replacement pins are one of three categories of bike chains.These chains need a special type of pin from the manufacturer to fix a break.If you don't carry these special pins with you when you ride, you may be out of luck in terms of repair options until you can make it to a bike shop.There are chains with links.Two pins are used to join the 2 ends of the chain.You may need to wait until you can replace the link to fix it.Chains with pins.If you have a chain tool with you, you can use uniform pins to repair a break.
Step 9: The bike has a damaged chain.
Getting rid of the old chain is the first thing you'll need to do if you decide that your chain will be easier to replace than to repair.Simply turn the pedals until the length of the chain has passed around the sprocket, and you can remove it.If the chain is still holding together, you may need to break it in order to remove it.You can use a chain tool.To use a standard chain tool, simply line up one chain link in the tool's internal grooves and push the pin out of the chain.If you want to reuse your chain, make sure you push the pin out of the way that the 2 links can't be separated.The pin is hard to replace, so don't push it all the way out.The broken chain can be passed through the bike's gears by simply turning the pedals.Ideally, you want to buy a replacement chain that's the same length as the chain you had before, though bikes with a rear derailleur allow a small margin of error, so now is a good time to count the links in your chain.The type of drivetrain you have should be taken into account as this determines which chains are suitable.9-speed chains are required for example.
Step 10: The back wheel needs to be raised.
Next you need to thread the new chain through the rear derailleur.It is easier to turn the back wheel if it is not on the floor.If you have a bike rack or hook on the wall of your garage that allows you to hang the bike with its sprockets facing you, use it.If you have wood, boxes, cinder blocks, or something else lying around, you may want to prop up the rear of the bike's frame.Take note of your derailleur arrangement.If your rear derailleur has a cable connected to your shifting mechanism, you should shift into the highest gear.Shift into the lowest gear if the front derailleur has a cable connected.
Step 11: The chain has to be pulled through the rear derailleur.
Most modern bikes have a spring-loaded system of gears hanging down below the main rear sprocket.It's important to thread the chain through the derailleur.Take the female end of the replacement chain and thread it around the bottom pulley and the top pulley.The chain should make a smooth, straight, backwards path through the derailleur.If the chain is resting on anything besides the pulleys, there will be a "bump" in your backwards "S".There is a small metal "tab" between the pulleys.The chain must not touch the tab.Fixed-gear bikes and bikes with a hub gear shifting mechanism don't have a derailleur.To turn the wheel in these cases, simply thread the chain onto the rear sprocket.
Step 12: Attach the chain to the cassette.
The cassette is the array of multiple sprockets attached to the rear wheel of the bike.Pull the chain up and over the smallest part of the cassette when it's threaded through the derailleur.Pull the chain through the rear derailleur and the sprocket to give yourself some slack at the lead end.
Step 13: The chain should go through the front cage.
The chain can be shifted from one front gear to another with the help of a metal mechanism near the front sprocket.Turn the rear wheel to give yourself more slack as you thread the lead end of your chain through this front derailleur.Fixie bikes don't usually have a front derailleur, so just thread the chain around the front sprocket.
Step 14: The chain needs to be put on the front sprocket.
The chain should be aligned with the smallest of the front sprockets.If you want to give yourself enough slack, Stretch it taught so that it engages securely with the teeth on the front sprocket, then pull it around the sprocket and turn the pedals.
Step 15: You need to connect the ends of the chain.
Once your chain passes through your gear system, you can join the 2 ends of the chain and ride again.Line up the "female" and "male" ends of the chain with a chain tool, available at all bike shops.To make sure the 2 ends of the chain are in the right place, hook them on to the tool's teeth.To connect the 2 links, turn the handle to drive the pin into the chain.Make sure the pin protrudes an equal distance from each side of the link, as even a minor misalignment can cause structural weakness in the chain, potentially leading to another repair.A small piece of metal called a "C-hook" can be used to hold the 2 ends of the chain together.It's much easier to work as you won't have to worry about holding the chain in place and potentially losing either end.A bent paperclip can be used as a substitute for a real C-hook.The pin that you use to connect the ends of the chain can make the link stiff if you don't use a master link.This can cause a problem with your pedal stroke.The links on either side of the stiff link should be in a direction that the chain rotates in.