How to Tighten a Dirt Bike Chain? – 5 Simple Steps

Written by

James Stevens

Fact-checked by

Robert A. Verdin

how to tighten a dirt bike chain

The chain on your bike is responsible for turning the rear wheel via the linking gear between the engine and the wheel called sprockets. Unfortunately, some hobbyists miss out on the wearing and tearing of this chain.

The dirt bike is especially one to have a fast degradation of its chain due to its build. It is often smaller is ⁠always on dirt tracks. As rust builds up quickly, the motorcycle chain tightness loosens over time.

You can visit a shop for regular dirt bike chain maintenance, or you learn how to tighten a dirt bike chain and do it by yourself with this guide.

5 Simple Steps to Tighten Your Dirt Bike Chain

What to prepare

Here is a list of the tension tools you need:

  • A 22mm to 32mm wrench/ratchet and socket (depending on your bike)
  • A 12mm wrench
  • A 10mm wrench
  • A ruler

Note that this is also a perfect time to check if the sprockets of your dirt bike have worn down by checking if the teeth are crooked.

Step 1: Clean the bike



Before yotighten the chain on your motorcycle–⁠remember–⁠dealing with a dirty bike (after all, it is a dirt bike) will be messy, so at the very least, you want to work with a spotless bike.

So securely place the bike on a motorcycle stand and start degreasing and removing the debris around the chain using a spray (like WD-40) and a cleaning rag or brush.

To make things easier, rotate the rear wheel as you degrease and brush and let the tools slide along the chain to make your cleaning duty more efficient.

Do this several laps around the bike chain to be sure no dirt is left behind.

Let the chain dry wholly, then apply a small amount of chain lube spread all over the chain. This way, moving and adjusting the chain on the motorcycle will be effortless.

Step 2: Loosen the Nuts


Locate the rear axle nut, which is either on the left or right side of the bike. Remove it using a crescent wrench or ratchet and socket with the proper size (22mm to 32mm).

Note that the initial attempts to turn the nut require a vast effort since manufacturers designed it to jam it tight.

Next, spot the dirt bike chain-adjuster bolts and locking nuts you see beside the axle nut and loosen both nuts on either side evenly–⁠this bit is crucial because it keeps the rear wheels balanced.

Usually, you can use a 12mm wrench to adjust these. But whichever wrench can fit is also acceptable.

Step 3: Adjust the Chain

Rotating the adjuster bolt outwards from the wheel will tighten the motorcycle chain, and adjusting in the opposite direction will loosen the chain.

Remember that you still want to turn these bolts evenly on either side using a 10mm wrench to keep the rear wheel set straight.

The dirt bike chain’s slack or tension standard is about 1 to 2 inches when the bike hangs on the stand and 1 inch to 1¼ inches when the bike sits on the ground.

Measure the length of the slack using a ruler while tightening or loosening the adjusting bolts to know if you’re in the right ballpark.

Step 4: Tighten the Nuts


If you’re satisfied with your dirt bike chain tension adjustment, torque the locking nuts back with a wrench.

Remember to hold the adjuster bolts in place using another tool to avoid changing the chain tightness. If everything went smoothly, the rear wheel alignment must still be straight.

To confirm if the wheel is aligned, you can use a ruler and measure the length of the axle or adjustment block to the end of the swingarm and see if it is the same on either side.

Next, tighten the rear axle nut using a wrench to seal the bike parts together.

Since this can be tricky to do because the chain will keep moving, one good idea is to use a piece of rag or cloth and stick it between the sprocket and chain, then pull the rear wheel back until the rag stops it, keeping it in place.

Step 5: Lube the Chain

The finishing touch is to lube the chain and sprockets to ensure a smooth ride and to prolong the life of your dirt bike parts. Keeping the chain lubed can also help avoid problems like a loose chain.

Using a chain wax specifically for a dirt bike is your best option since it keeps your parts greased up while also repelling dirt. But if this is unavailable, sticking to the trusty WD-40 is acceptable.

How Tight Should Your Dirt Bike Chain Be?


There is no explicit rule on how tight a dirt bike chain be. But remember that firm chains wear the sprocket more, and loose chains might cause it to fall off from the sprocket. According to most manuals and most people, there must be a 1-inch to 2-inch (50mm) allowance between the swingarm and the chain.

If you do not have any measuring tools available, the easy way is to use the finger rule. Slide your fingers between the center of the swingarm and the chain. If you can fit 2-3 fingers in between, that’s the proper motorcycle chain tension.

Why is My Dirt Bike Chain Loose?


The main reason why a chain can be loose is it most likely has worn down already. But sometimes, it gets loose more quickly than we expect. Here is a list of reasons why:

  • The tensioning bolts or axle nuts are not screwed tight enough. These bolts pull down the rear wheel, which also houses the chain. Having it loose means the chain’s stretch will also likely be floppy.
  • Although rare, a worn-down sprocket’s teeth can loosen the chains quickly. These teeth will not have much contact with the chain, making it appear stretched and loose.
  • The size of your chain is different. Each type of motorcycle has a specific chain size to pair it with, so be sure you are using the correct size. If you’re unsure, check that the teeth of the sprocket should line up perfectly with the chain.

How Do I Know if My Dirt Bike Chain is Too Loose?


The first thing to do is look for obvious ones, like if the chain is hanging free from the sprocket. Another thing is if the chain alignment to the sprocket is off, meaning it’s not sitting along the teeth perfectly and might fall off anytime soon.

However, if you think it’s loose but not so obvious, you can also sit on the motorcycle and check how much tension the chain has. The right tightness while sitting on the bike must be about an inch.

You can also check using the finger rule between the swingarm and the chain. It’s loose if you can fit four or more fingers. So it’s time to tighten the chain on your bike.


After all this, you should know that a street motorcycle differs from a dirt motorcycle. Driving on a trail with your dirt bike is more exciting and fun than street ones, even though cycling through rough terrain always presents danger and uncertainties.

With it, you’ll never know when a part will pop out of your motorcycle, especially if you’re attempting extreme maneuvers. So for starters, learning how to tighten a dirt bike chain can prevent future problems or accidents and save a lot of money.

5/5 - (3 votes)

James Stevens

James Stevens is an expert bike mechanic who knows everything from basic repairs to custom modifications. What sets him apart is his ability to explain complex concepts in a way that's easy to understand. Check out his content on Speedway if you need help with upgrades or modifications for your bike.