A Complete Guide on How to Tighten a Bike Chain Safely

If you’re a professional or avid biker, you probably know the dangers of your bike chain getting loose. It’s bound to happen after riding for some time and can happen for many reasons. That is why you should know how to tighten a bike chain by yourself. 

A new bike chain can get loose if you place it on an old bike. The worn-down components of your old bike will cause your new chain to jump and slide as you ride. That eventually makes your bike chain loosen up.

Although a loose chain isn’t dangerous, it’s still annoying. It makes your pedaling less efficient and require you to put in more effort. Read on to our complete guide on how to tighten a bike chain with a derailleur or on a single-gear bike.

How Does a Bike Chain Function?

Multiple steel components make up the bike chain. That includes multiple pairs of outer plates and inner plates held together by rivets. 

A roller separates each pair of inner plates and presses the rivets through both outer plates. Then, the rivet is free to pivot on the roller and inner plates. There is a 0.5-inch gap between the rivets in most modern bicycles. 

The bike chain’s job is to generate energy and power from your pedaling to ensure a smooth ride. Unfortunately, once the bike loosens, the power drops. That means you’ll have to put much more energy into your pedaling, making it nearly impossible to ride. 

There are two types of bike chains; derailleur and single-gear chains. We’ll tell you how to tighten a loose bike chain or both types. 

How to Tighten a Bike Chain with a Derailleur

Derailleur chains are significantly different from single-gear bike chains. These chains move from sprocket to sprocket. There are several different designs of derailleur chains, depending on the number of sprockets. 

A rear cog can have anywhere between 5 to 12 sprockets. The more sprockets there are, the less gap is between cogs. The number of rear cogs also affects the narrowness of the chain.

A “3/32-inch chain” is another name for derailleur chains, even though they vary in size.


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    Here’s a step-by-step guide on how to tighten a bike chain with a derailleur.

    Step 1: Put the bike in the correct position

    The first step is to position your bike correctly for viewing. The quickest and simplest option is to flip your bike upside down. That will help you locate the derailleur and access the wheels easily. 

    Step 2: Locate the derailleur screw

    The next step is to locate the derailleur screw, which should be easy since your bike is in the correct position. The derailleur is a complicated-looking component consisting of cogs and screws.

    Commonly, you’ll find a “B” engraved adjacent to the screw behind the derailleur. This screw will help you tighten a bike chain quickly. All you have to do is twist it clockwise to increase chain tension. 

    Step 3: Access the rear tire

    Next, you have to access the rear tire to increase the derailleur chain tension. This step will require some dismantling, so you must stay vigilant.

    First, you have to disconnect the brakes from the cable. Then, you can lift the brake lever, which will help you access the rear tire. 

    Step 4: Adjust the rear Tire

    Now that you have access to the rear tire, you can finally adjust it. Adjust the wheel axle such that the tension on the chain of the derailleur increases. Now, you can count on your bike chain to stay taut while you ride.

    However, make sure you don’t tighten the derailleur chain too much, as it can cause interruptions in your riding.

    Step 5: Put everything back together

    Finally, the last step is to put everything back together and test your bike. Reconnect your brakes and tighten your screws one last time to achieve good chain tension. Spin the wheels once to see if they’re touching the chain or frame.

    If they’re touching neither, you’ve tightened your bike chain successfully. Lastly, you can take your bike for a ride to see if everything’s working smoothly!

    How to Tighten a Bike Chain on a Single Gear Bike

    Unlike derailleur chains, single-gear bike chains only have one sprocket on the crankset. The other sprocket is on the wheel. The roller on this bike is commonly one-eighth of an inch in width.

    That’s why they’re also known as “one-eighth inch” chains. Since single-gear bikes don’t shift speeds, they don’t need multiple rear cogs. A wider chain and sprocket results in a longer chain life and ease in downhill biking. 

    Read on to find a step-by-step guide on how to tighten a bike chain on a single-speed bike.

    Step 1: Put your bike in the correct position

    Firstly, you have to place your bike in the correct position. If you’re a professional biker, your instinct would probably be to set your bike upright. However, the easier option for an amateur is to turn the bike upside down.

    That will help you access the necessary parts easily. If you want to protect your bike from scratches, you can lay cardboard under it. 

    Step 2: Loosen the rear axle

    The next step is to loosen the rear axle. To loosen the rear axle, you have to fix a wrench on the bolt head and twist. Then, you can spin it clockwise until all the threads are somewhat loose. 

    Step 3: Pull back on the rear tire

    After you’ve loosened the rear axle, you can pull back on the rear tire. Next, use a socket wrench to remove the nuts that connect the rear tire to the bike. You can slowly rotate the nuts in a counterclockwise direction until you’ve loosened them just enough.

    Then, you can go ahead and pull back the rear tire. Continue this until you feel you’ve reached an optimum level of chain tension.

    Step 4: Make sure that you have the right chain tension.

    To ensure your chain tension is correct, analyze your bike once again. First, make sure that the bike chain only moves half an inch when you spin the wheels. If it moves more than half an inch, it means your chain is still loose.

    However, if it moves less than half an inch, you will have trouble pedaling smoothly. 

    Step 5: Tighten the rear tire back into place

    Once you’ve achieved your desired chain tension, you must fix your real tire back into place. You can do this by tightening the axle nuts once the wheel is back into place.

    Step 6: Test the chain and the tire

    Lastly, it would help if you spun your wheels once again to ensure your bike is in the optimum setting. If your wheels do not touch the chain or frame while spinning, it means you’ve succeeded at tightening the chain.


    Here are the answers to some frequently asked questions about bike chains and their working.

    How do you adjust the tension on a bike chain?

    To adjust chain tension on a mountain bike, you must locate the screw behind the derailleur. You’ll find a “B” written adjacent to it. Then, use your screwdriver to twist the B-tension screw and adjust chain tension.

    How do you tighten a loose bike chain?

    Tightening a loose bike chain yourself isn’t as complicated as it seems. For a single-speed back, you must first loosen the rear axle. Then, you can pull back on the rear tire to increase chain tension. 

    Tighten the rear tire again, and voila! You’ve successfully tightened a loose bike chain.

    How do you fix a sagging bike chain?

    Fixing a sagging bike chain with a derailleur is simple. All you have to do is twist the screw behind the derailleur to increase chain tension. Then, you can adjust the rear axle such that the chain is taut. 

    Lastly, put everything back together, and you’ve successfully fixed a sagging bike chain.

    What happens when the bike chain is loose?

    The loosening of a bike chain isn’t necessarily dangerous; it’s bothersome. It wastes your energy by making you put more effort into pedaling. Since the chain generates energy into the ride while you pedal, the power drops once the chain is loose.

    Tightening your bike chain is essential to avoid interruptions and low speed when you ride.


    A loose bike chain is nothing more than a hurdle between you and a smooth ride. It isn’t particularly dangerous, but it does waste your energy. In addition, the loosening of your bike chain will force you to pedal harder.

    It’s important to learn how to tighten a bike chain to ensure a smooth and interruption-free ride. If you’ve read our complete guide, that should be a piece of cake for you!

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    A Complete Guide on How to Tighten a Bike Chain Safely — Bike Hacks