Why Chainsaw Chain Tension Matters
The right chainsaw chain tension is critical to safety. A chain that’s too loose or too tight can cause severe injuries:
- A loose chain can kick or push the saw back at the operator or derail from the guide bar.
- A chain that’s too tight can snap while you’re cutting and derail.
Chain tension also affects your work and saw, leading to poor cutting, overheating and wear on the saw, bar and sprockets.
How Tight Should a Chainsaw Chain Be?
Check the tension of your chainsaw chain before every use and each time you refuel the saw:
- The chain shouldn’t sag.
- The chain should fit snugly, with the strap ties — the parts that connect the cutting teeth and drive links — lightly touching the bar.
- With the saw off, the spark plug wire or power disconnected, and the chain brake released the chain should move smoothly around the bar with a tool or gloved hand.
Adjusting a chainsaw chain is a key part of maintenance. See our guide to using and maintaining a gas chainsaw or using and maintaining a battery-powered chainsaw for more maintenance tips.
Chainsaw Maintenance Safety
Follow the chainsaw manufacturer’s instructions for use, maintenance and safety. Your manual has specific instructions, but in general, before any inspection or maintenance:
- Allow the saw to cool.
- Disconnect the spark plug wire on a gas chainsaw and disconnect an electric saw from power.
- Wear heavy-duty work gloves or chainsaw safety gloves.
Read our chainsaw safety article to learn more tips on using a chainsaw correctly.
How to Adjust a Chainsaw Chain
We’ve got general steps for loosening and tightening a chainsaw chain, but the process varies by model. Follow the steps for your saw.
Step 1: Loosen the Bar Retaining Nuts or Knob
Disengage the chain brake. Depending on the saw model, there are bar retention nuts or a knob securing the guide bar and drive sprocket cover. Loosen the nuts with a wrench or chainsaw scrench tool or loosen the knob by hand. Your instructions might tell you to leave the bolts hand tight or loosen the knob a half turn. Don’t loosen the bolts or knob completely.
Step 2: Adjust the Chain Tension
Lift the tip of the guide bar before adjusting the chain. If your saw has retention nuts, there’s typically an adjacent tensioning screw or a screw at the base of the bar, next to the engine. Use a screwdriver or scrench to turn the screw and tighten or loosen the chain. If your saw has a retaining knob, there should be a tensioning wheel nearby or integrated with the knob. Turn the wheel to adjust the chain.
Step 3: Check the Chain Tension
Pull the chain away from the bar. You shouldn’t be able to pull the guide links out of the bar groove. When you release the chain, it should snap back against the bar. With the bar supported and the chain brake disengaged, move the chain around the bar using a screwdriver, scrench or your gloved hand. It should move freely without sagging. Continue to adjust the tension as necessary.
Correct tension varies depending on your bar type. Follow the specifications for your saw, chain and bar.
Step 4: Retighten the Bar Nuts or Knob
Keep the bar supported. Retighten the retention nuts or knob according to your saw instructions. Periodically check the chain tension the next time you use the saw, adjusting as necessary.
Follow the manufacturer’s instructions for using a chainsaw. Check the bar and chain oil level. Wear safety gear, including a helmet, eye protection, hearing protection, chainsaw safety gloves and chainsaw chaps.
Key Takeaways for Tensioning a Chainsaw Chain
Stay safe, cut efficiently and get maximum life out of your chainsaw by making sure the chain has the right tension:
- Allow the saw to cool.
- Disconnect the spark plug wire or disconnect power before any maintenance.
- Wear heavy-duty gloves.
- Release the chain brake and loosen the retention nuts or knob.
- Lift the bar tip and turn the tension screw or wheel to adjust the chain.
- Make sure the chain is snug and moves freely. Lift the bar tip and re-tighten the bolts or knob.
At Lowe’s, we’ve got everything you need to keep your saw safe and running smoothly. Shop Lowes.com for chainsaw chains, bars, maintenance tools, safety gear and more. Or stop by your local Lowe’s and talk to a Lowe’s Red Vest associate. From bar and chain oil to sharpening tools and new chains, they’ll make sure you have everything you need for the next job.
Chainsaw Tension FAQ
Use the answers to these questions to help you tension your chainsaw chain correctly.
Why Is the Chain so Loose on My Chainsaw?
There are several possible reasons for a loose chain. Heat from use expands and loosens the chain. A new chain loosens frequently during its wear-in period. Incorrect chain installation, poor cutting technique and worn parts can also lead to a loose chain. Follow the use and maintenance steps in your saw manual and make sure your chain is right for your model. Make sure the tension is correct before and during use.
Where Is the Tension Screw on My Chainsaw?
On some saws, the tension screw is on the blade side of the saw, near the bar retaining bolts. On other models the tension screw is next to the engine, at the base of the guide bar. Some smaller saws have a tensioning wheel, instead of a screw, on the blade side of the saw housing.
What Are Signs of an Overtightened Chainsaw Chain?
Disconnect the spark plug wire or the power supply and release the chain break. Try moving the chain with a screwdriver or gloved hand. If the chain binds, it’s likely too tight. Overheating and excessive bar wear are other signs of a tight chainsaw chain.