If you ride your bike often, you should expect to encounter a loose bike chain at some point. It might happen often, it might happen rarely, but what’s certain is that it will happen at some point, so it’s best to prepare by learning how to tighten a bike chain. After all, tightening a bike chain is not difficult as long as you have the right tools at your disposal. And, trust us, you don’t have to be a mechanic to do it—it is really simple.
The chain is, of course, one of the most important parts of the bike. You won’t be getting very far without it. It’s the mechanism by which power from the pedals is transferred to the wheels of the bike, propelling the whole thing forwards. A loose chain will thus result in a less than optimal transfer of power, making the rider have to pedal harder than was previously necessary.
Not just that; a loose chain also risks falling off the sprocket entirely, which can get your bike damaged or cause you to get into an accident.
So if your chain is loose or is sagging up, you need to get on the task of tightening it up immediately. Don’t procrastinate in getting on with this minor task because a loose chain will at best give you a horrible ride, and at worst be a safety issue.
For Single-Gear Bikes
Firstly, turn the bike on its head, resting on the bike stand or standing on its handlebars and saddle. Basically, the wheels have to be in the air. This will make it easier for you to access the rear tire. If you don’t have a bike stand, you can let it rest on a piece of paper or cardboard to avoid scratching both the saddle or handlebars.
Next, loosen the rear tire. You can do this by using a socket wrench to loosen the bolts that attach the tire to the rear axle.
Now that the tire is loosened from the rear axle pull it backwards to increase the tension. Don’t pull it too much or yank it abruptly because that might cause the chain to break! Pull it back slowly until you’re certain the tension is right. Typically, the proper tension will permit you to move the chain half an inch upwards and downwards. If your chain has this much slack in either direction, then the tension is just about right.
Once you’ve got the proper tension, simply re-tighten the wheel in place and make sure each bolt is secure. Also, you want to make sure that the tire is centered on the frame, neither touching the chain or the frame.
Next, test the tire by spinning it. Is it moving properly? Test the tension in the chain once more by moving it upwards and downwards. Does it have at least half an inch of slack in either direction? If your answer to those two questions is “yes,” then you’re good to go.
For Multi-Gear Bikes
1. Same as for single-gear bikes, you need to be able to access the rear wheel and derailleur. So place the bike on its head either on a bike stand or resting on its saddle and handlebars. Again, if you don’t have a bike stand, you might want to let the overturned bike rest on a piece of paper or cardboard to avoid scratching both the saddle and handlebars.
2. Next, you want to access the derailleur, particularly the screw located at its back. Most bikes will have this screw next to the letter B, which will make it easy to identify. If you see a screw behind the derailleur next to a letter B, then you pretty much have it. Now turn that screw clockwise to increase the tension.
3. The next step is to access the rear wheel to adjust it. But before you can do this, you’ll need to release the lever on your breaks so you can detach the cable. Once the cable is detached, raise it up to access the rear wheel.
4. Now that you’ve got access to the rear wheel, you can move it backwards ever so slightly to increase the tension. After that, lower the quick-release lever and check if the tension is fine. If you find that the chain still needs more tension, simply raise the quick-release lever and move the wheel backwards again slightly, then lower the lever and check once more. Basically, just keep repeating the process until you’ve got the proper tension, or until the chain has about half an inch of slack in either direction.
5. Next, you will need to put everything back together (naturally!), paying extra close attention that the derailleur screw is fitted properly and securely. Then check the tire by spinning it a couple of times, making sure it’s centered on the frame and not hitting either the frame of the chain (or any other part of the bike, really).
If you bike often, you’ll need to be doing this a few times in your life anyway, so you might as well make yourself well-versed in the matter. Bike chains will eventually come loose at some point, so it’s best to be prepared. Indeed, tightening a bike’s chain is somewhat of a right of passage among bike riders, and by repeating the steps above, you can be a bike chain-tightening expert in no time!