If you find that your chain keeps dropping off or coming loose, you will need to tighten it to prevent an accident.
As an experienced cyclist who has fixed chain issues on many a roadside, I can tell you that it doesn't mean that there's a problem with the bike. It likely means that there's not enough tension in the chain and it doesn't fit properly anymore.
I'll walk you through the steps on how to tighten a bike chain below.
One thing I will say before we kick off is that if you've just bought a brand new bike, the gears will slip as you're cycling. This will only get worse overtime.
After about 6 weeks of cycling, you will need to take it back to the bike shop and ask the seller to reduce any slack and ensure the chain is tight. They will also do a mini service on your bike. After this, you will notice a difference!
This is all perfectly normal, and is to be expected. Once the components are in use, they will stretch.
Let's get to the easy steps and process of tightening a chain.
If you're new to the cycling world, you might be wondering what a single speed bike is.
Watch this video for a full explanation:
In short, a single-speed bike has only one gear.
There will be a cog where the freewheel mechanism would be on the rear wheel.
As you pedal, the cog turns, causing the wheels to turn.
So now that we've got that down, let's go about tightening the chain.
You're going to need the following tools:
If this is something you've never done before, or are not used to doing, I highly recommend that you either use a bike stand or turn your bike upside down so that you are able to access the parts.
To be able to complete the job, you'll need to remove the axle nuts holding the tire to the bike.
You are likely going to need the socket wrench for this.
Now, remember, "righty tighty, lefty loosy" so turn the nuts in an anti-clockwise direction with the socket wrench to get them to loosen up.
What this will achieve is that you can increase the tension in the chain. You need to pull the rear tire until you achieve the right chain tension you're after.
This is a slow process - don't be tempted to speed it up as you can end up snapping the chain.
You want to keep checking the tension as you're pulling back to get the right tightness. What you're aiming for is to move the chain either way about half an inch.
Tip - Ensure that the tire stays in the wishbone. This will make tightening it easier.
You know you're aiming to have the chain moving 1/2 inch in either direction. Let's go into a little more detail on this.
What you will notice is that when the tire is pulled back, the tension on the bike chain will change.
Should you move it too far in one direction , it signifies that there isn't sufficient tightness. You need to push it more on the tire.
If you've got too far and it's too tight, you will know about it. The pedals won't be able to turn, so to save yourself a lot of hassle, it's important to get this step right the first time.
When you are satisfied that the bike chain tension is just right, it's time for the rear tire to be put back into position.
Screw the loose nuts back onto the wheel axle.
I'd recommend doing this step by step. You should use the socket wrench (screw clockwise this time) to ensure that you achieve the ideal tension.
Ensure that the back tire is in the correct position against the bike frame. When it's in the correct position, it won't make contact with the bike frame or bicycle chain.
Once everything is in place, you're going to want to test it before going out on a ride.
Move the bike chain in both directions, and you should find that it moves about half an inch in either direction.
I'd also recommend that you spin the rear tire to check that it's moving as it should. You don't want it to come into contact with the frame or the chain as you're riding.
If it does, it means that you've gone wrong somewhere and need to attach the rear tire back again.
However, if done right, you should find that the loose chain on your single gear bike is roadworthy once again!
Here is a guide from Park Tools on how to size your chain correctly:
When a bike chain comes off single-speed bikes, it doesn't present much of a problem. The same can't be said when you find yourself with a chain that is loose on a multi-gear bike.
It can lead to your foot getting caught in the chain and, well, to be honest, quite a serious injury.
If you think that the chain tension on the multi-gear bike isn't as tight as it should be, the best thing you can do is stop riding it. Either take it to a reliable bike shop or have a go at fixing the bike chain yourself.
If you have a bike stand, attach your bike to it. Otherwise, turn your bike on its back and you'll be able to reach the derailleur easily.
There is a screw located at the back of a derailleur on multi-gear bikes.
On the majority of bikes, there is the letter B and next to that, you'll find the screw.
If you want to increase the tension of the chain, turn it in a clockwise motion.
This is different than on a single-gear bike because multi-gear bikes have brakes.
You need to disconnect the brakes from the cable. This will give you access to the rear tire
You need to slide the rear axle in the direction of the rear dropouts. This is what will increase the tension on the bike chain.
It's all about small adjustments as you don't want the bike chain to be tightened too much.
After you make an adjustment, lower the brake lever. This will give you an opportunity to check the tension on the bike chain.
If it's not quite tight , lift up the lever and make another adjustment. Keep going until it's tight enough.
When you are happy with how the chain is, then it's time to put everything back to how it was.
First, make sure the derailleur screw is tightened sufficiently.
After that, you'll need to ensure that the tire is able to spin freely and doesn't make contact with the bike frame or the bike chain.
If you find that you aren't happy with the tension of the bike chain, repeat the process.
That's it. All done!
I know that this may seem a bit drawn out. However, once you've done it a few times, you'll find that it is a quick job.
Tip - Wear a pair of rubber gloves. You're going to dirty. Having a rag will help you wipe away any additional lube too.
Even if you maintain your bike regularly, you will still find that the chain becomes loose over time. There are several reasons for this.
The most common one is that it's a new chain on an old bike.
A new chain won't fit an old bike perfectly. The parts of an old bike will be worn, so it's not a great fit. This can cause the bike chain to jump around and eventually come loose.
Should this happen to you, you can tighten your bike chain - follow the above steps and you're all good.
It doesn't mean that an old bike chain won't become loose either... because it will. Bike parts wear with use. It can't be helped and over time, they won't fit as they should and inevitably come loose. When it's an old chain, the best thing you can do is get a new one, rather than trying to tighten it.
Another reason is that axle nuts can become loose on the rear axle. The distance may have been shortened between the pedals and the wheel.
If you're on a multi-gear bike, that could mean that there is derailleur damage. So if you find that you have to adjust the chain tension frequently, it could be that your derailleur is bent or has dents.
When you tighten a bike chain, you want to feel movement of about 1/2 an inch in either direction.
If you want to know how to tighten a bike chain, the above tips should help you.
However, if you find that the chain tension is still too slack, that could be because the chain has expanded. What can happen is that the links do stretch overtime. To get the right tension, removing some links this should solve the problem.
Proper maintenance of bike chains will extend their life.
If you ride with a dirty chain and don't lubricate it, rust will appear and the chain will wear down more quickly. It will also slacken faster.
By lubricating your chain (and performing regular maintenance), you are protecting it and making it easier for the chain to do its job. It will mean that you won't have to tighten the chain as often. Nor will you have to replace it as often!
I get it, some people aren't into bike maintenance or don't have a bike stand. They may not want to attempt fixing a loose chain at all.
Find a decent bike shop and ask them to perform regular maintenance on your bike. This will depend on how often you ride, but let's say on a monthly basis.
This will give them a chance to make small adjustments. The chain will be cleaned and oiled often. They would monitor and make sure there's enough tension as well.
If your chain is loose because it's old, then get yourself a new one.
New chains are expensive and they extend the overall life of your bike - especially the rear derailleur.
However, if the chain is new, then most likely you need to tighten it.
Want to know how to remove your chain and replace it? GCN will show you how here:
Bike chains can become loose for a number of different reason. It's nothing to worry about. However, if you know how to tighten a bike chain yourself, then it does make life easier.
One thing you need to remember is that multi-gear bikes work differently from single-speed bikes. So the process to increase tension is slightly different.
If you have the right tools, a rag handy and some confidence, follow the steps outlined above. If you don't want to do things yourself, a bike shop can show you how to tighten a bike chain quickly. Just ask them to do it for you!