How to tighten a bike chain

Ever come back from a long bike ride, or go to dust off that bike in the garage and notice that the bike chain is hanging from the spokes. Or just notice that the chain itself isn’t as tight and fluid shifting gears as it used to be. Well then it might be time to get a new chain or fix your old one. So let’s tackle this common cycling problem of how to tighten a bike chain.

Having a working, well maintained bike chain is obviously crucial to you being able to ride your bike and compete. So when the chain is not running in two parallel lines across the spokes then we have a problem!

There is a series of steps you need to take to see if your chain is something that can be fixed, or if it something you need to replace.

Common Checks for Tightening a Bike Chain

Is your bike chain fit into the derailleur correctly?

When you are see how to tighten your bike chain, the first thing you should check is if it is threaded through the derailleur properly. The bike chain should run through the derailleur in a nice “S” shape, if it is not doing this it can be a common and easy fix to tighten your bike chain. However it should not be pulled tightly through causing the derailleur to be pointing towards your front wheel! You should also make sure that the derailleur has a nice spring to it. If your derailleur is very stiff then you may need to look into replacing your derailleur , which in turn could fix tightening your bike chain as well!

You can also check the “B” screw at the top of the derailleur , this is the screw that pulls the derailleur back so that it is pointing more perpendicular to the floor. However if your derailleur looks to be in good condition, has nice spring to it and the chain is still droopy well then this is most likely not the issue.

Check your wheel positioning

Another item that could be off is your rear wheel positioning. Slide the bike wheel as far back in the frame as possible, if this is possible for your bike. Does the bike chain get any tighter? Is it still sagging? If so then this is not the issue! And return the wheel to its normal placing and bolt it down. I have never done maintenance on a bike and had this be the issue, but since it is a simple check that takes a minute it is always better safe than sorry before making a purchase.

How worn down is your bike chain

Lastly, assuming other parts are functioning as expected we are now narrowed down to this being a chain issue. But first we need to break out a chain gauge to find out for sure. If you don’t have one you can pick one up relatively cheap! This is a good tool to have for bike maintenance if you are the DIY kind of person, or you just want to always protect your investment and have your bike in top working order.

Once you have your chain gauge, slide your chain gauge in place, first at the .75 gauge and then at the 1.0 gauge. If the bike chain gauge slides in nice and easy in one or both of these areas you are dealing with a very worn bike chain that you will not be able to tighten.

Bike chain too long for bike?

If your chain gauge checked out and it did not slide easily in place you could also be looking at a chain that is too large for your bike. This will only be the case if you bought your bike second hand. Any bike you get from a manufacturer or bike shop is going to have a proper chain on it. However if you want to check this you can take a bent clip about two inches long to pull some of the chain together (watch the above video if you missed this!) This way you can see what removing some chain length would do to your derailleur. If it pulls it forward, as I mentioned above then this is making the chain too short! If you can remove a couple inches of chain and the derailleur maintains the correct position then you would have an incorrectly fitted chain.


A lot of people get a bike chain drooping after years of riding and start asking how to tighten a bike chain. Sadly, if you got your bike from a manufacturer or have had it in your possession for a long time you will most likely be looking to replace your bike chain instead of tightening your bike chain. Fortunately you can pick up bike chains cheaply as well and they are easy to install. I hope that this guide has helped you diagnose if you can tighten your bike chain or if you will need to replace it and I wish everyone happy cycling!

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