How to tighten your chainsaw chain
For your chainsaw to work at its best and keep you safe, the chain must be at the right tension. Learn how to tighten it with our guide.
12.11.2024
How can I tell when I need to tighten my chainsaw chain?
You need to tighten your saw chain every so often because it is the part that encounters the most strain when you use your chainsaw: every time a tooth goes into wood, the chain experiences an abrupt peak of stress in terms of impact and friction. The accumulated abrasion, dirt, and sawdust generated also cause additional mechanical wear on the sprocket, chain and other parts. So it’s no surprise that the chainsaw tension will need adjustment over time.
If you can see that the saw chain no longer fits to the bottom of the guide bar, you need to tighten it – a correctly tensioned saw chain is snug to the underside of the bar but can still be easily moved round by hand when the chain brake is released. If you have a STIHL chainsaw with QuickStop Super, you also need to press the brake lever on the lower handle to release the chain brake. Be aware that the saw chain heats up during normal operation and therefore expands; you should also tighten the saw chain if it has more play after heating up.
If you tighten the saw chain at operating temperature, remember to loosen it – reduce the tension – again once it has cooled down. If the chain tension is too high, it puts extra strain on parts of the chainsaw, which could cause damage.
We recommend you check the chain tension every time, before you use your chainsaw.
Note: remember to consider your own safety when you check or tighten your chain
- Never check or tighten the chain when the chainsaw engine is running.
- Wear suitable protective gloves.
- You can burn yourself on hot parts of the chainsaw engine or muffler if you try to check or tighten the chain at operating temperature.
- For a cordless or electric chainsaw, take the necessary measures to ensure that it cannot turn on (remove the battery, disconnect the plug).
- Check the saw chain for wear or mechanical damage (cracking, chipping, distortion) and do not use your chainsaw if the chain is damaged.
Tighten chain with a side chain tensioner – step-by-step instructions
The side chain tensioner is a tried-and-tested component of most STIHL chainsaws. It provides convenient access to the chain tensioner part and reduces the risk of contact with hot parts of the chainsaw engine.
If you have a model with QuickStop Super, remember to press the QuickStop lever on the rear handle when you try to move the chain around.
This describes fuel injection systems which inject the fuel mix directly into the combustion chamber.
In this type of fuel injection system, the fuel is injected directly into the crankcase at an early stage of the compression process. An advantage of this approach is that it means the injection pressure that needs to be overcome is relatively low. Atomisation and heating of the fuel is achieved by the piston’s motion to the top dead centre, and the increased compression that results from this motion. This type of fuel injection system is used in the STIHL TS 500i cut-off machine.
This type of fuel injection system is also known as manifold injection. Fuel is injected into the engine’s intake manifold, from where the piston takes in the prepared fuel-air mix. With this method, the fuel-air mix can be fed to the piston extremely efficiently, which is of huge benefit to internal cooling. The revolutionary STIHL MS 500i chainsaw includes this fuel injection system. Read on to find out more about this extraordinary innovation.
Shut off the engine. If you have a cordless chainsaw remove the battery, and for an electric one disconnect the mains plug.
Release the chain brake by pulling the chain brake handle towards you.
Use the KombiTool to loosen the fixing nut or nuts on the chain sprocket cover, but don’t unscrew the nut completely; it’s usually enough to loosen it by one or two turns.
Lift the chainsaw guide bar by the tip, particularly if it is long. Hold it up.
Turn the tensioning screw clockwise with the KombiTool screwdriver until the tension is correct.
Pull or push the chain round the guide bar by hand to distribute the chain tension evenly. You may need to slightly tighten or loosen the tension after doing this.
Tighten the fixing nut or nuts with the KombiTool.
After you have tightened the fixing nut, you can bring the chainsaw guide bar back down again.
To check the tension, pull the chain to see if it moves around easily – you must wear protective gloves to do this. The chain should move around the guide bar without a problem but also fit snugly to the bottom of it. Try lifting the top part of the chain at the middle of the guide bar too; it shouldn’t lift more than around 5 mm.
Rather than using your hands to pull the chain around, you can instead use the shaft of the KombiTool supplied; this reduces the risk of injury as you do not come into direct contact with the teeth of the chain.
Tighten chain with a front chain tensioner – step-by-step instructions
Only a few STIHL chainsaws have a front chain tensioner. They work in the same way as the side chain tensioner, and are just in a different position.
Shut off the engine. If you have a cordless chainsaw remove the battery, and for an electric one disconnect the mains plug.
Release the chain brake by pulling the chain brake handle towards you.
Use the KombiTool to loosen the fixing nut or nuts on the chain sprocket cover, but don’t unscrew the nut completely; it’s usually enough to loosen it by one or two turns.
Lift the chainsaw guide bar by the tip, particularly if it is long. Hold it up.
Turn the tensioning screw clockwise with the KombiTool screwdriver until the tension is correct.
Pull or push the chain round the guide bar by hand to distribute the chain tension evenly. You may need to slightly tighten or loosen the tension after doing this.
Tighten the fixing nut or nuts with the KombiTool.
After you have tightened the fixing nut, you can bring the guide bar back down again.
To check the tension, pull the chain to see if it moves around easily – you must wear protective gloves to do this. The chain should move around the guide bar without a problem but also fit snugly to the bottom of it. Try lifting the top part of the chain at the middle of the guide bar too; it shouldn’t lift more than around 5 mm. Rather than using your hands to pull the chain around, you can instead use the shaft of the KombiTool supplied; this reduces the risk of injury as you do not come into direct contact with the teeth of the chain.
Operating instructions for STIHL chainsaws
Download the operating instructions for your STIHL chainsaw here at your convenience.
Summary: how to tighten a chainsaw chain
If your saw chain is not fitting snugly to the underside of the guide bar, it’s time to tighten it
Shut off your chainsaw engine; remove the battery if it’s a cordless chainsaw; disconnect the power supply if it’s an electric chainsaw
Place the chainsaw on a firm, level surface
Release the chain brake
Follow the instructions depending on your chainsaw tension adjustment features, and tighten the chain appropriately. Check the tension
Don’t forget to wear safety gloves so that you don’t injure yourself on the sharp teeth of the chain
