If you are wondering exactly how tight a chainsaw chain should be, the answer is a precise balance: A properly tensioned chainsaw chain should sit snugly against the bottom of the guide bar, but you should still be able to pull it around the bar smoothly by hand. When you pull the chain down from the centre of the bar, the drive links should not come completely out of the bar groove, and it should "snap" right back into place when released.
Getting your tension right isn't just about cutting efficiently; it is the most critical safety and maintenance check you can perform before pulling the starter cord—especially when dealing with dense Australian timber.
Here is the Alpine Chain Co. definitive guide to chainsaw tensioning.
The Danger of Incorrect Tension
Running a saw with improper tension is the fastest way to destroy your gear, or worse, cause a serious injury.
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If the chain is too loose: It can jump the guide bar (derailment). At best, this ruins your drive links; at worst, it causes a severe safety hazard by whipping back toward the operator.
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If the chain is too tight: You will create excessive friction. This burns the bar rails, prematurely wears the chainsaw's sprocket, stretches the chain, and puts immense strain on your engine's crank bearings.
How to Check Your Tension: The "Snap Test"
To check if your chain is tensioned correctly, perform the Snap Test:
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Safety First: Ensure the chainsaw is turned off. Always wear heavy-duty work gloves.
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The Pull: Grab the chain at the bottom center of the guide bar and pull it straight down.
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The Visual Check: Look at the drive links (the shark-fin-shaped teeth that ride inside the bar). The tips of the drive links should remain inside the groove of the bar. If they come completely out, the chain is too loose.
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The Snap: Let go of the chain. It should immediately and sharply snap back into its snug position against the rails. If it sags, it needs tightening.
The Golden Rule: Never Leave a Hot Chain
This is the most common mistake made by new operators. As you cut, the friction heats the steel chain, causing it to undergo thermal expansion (it gets longer).
If your chain is hot and loose after cutting, tighten it suitably for the duration of the work you are doing. Ensure you then loosen your chain after working so when it cools down in your shed it does not put excessive force on the bar and sprocket. This shrinking creates extreme tension that can snap the chain or permanently damage your saw's internal bearings.
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Pro Tip: Always loosen the bar nuts slightly when you finish cutting for the day to allow the chain to contract safely.
The Australian Hardwood Factor
Why are we so obsessed with tension at Alpine Chain Co.? Because cutting Australian hardwoods like Ironbark, Yellow Box, and seasoned River Red Gum creates violent vibrations and massive heat.
This extreme environment causes chains to "stretch" (heat and wear and tear) much faster than cutting European pine. When cutting Aussie hardwood, you must check your tension at multiple intervals during your work, but never when the saw is on.
When to Stop Tensioning and Start Replacing
A chainsaw chain does not last forever. If you are constantly having to tighten your chain, or if your chainsaw's tensioning screw is maxed out and the chain is still sagging, the chain is fully stretched. Continuing to use it is a massive safety risk.
Don't risk your saw or your safety on a stretched chain. If your chain is out of adjustment, it’s time for a replacement. Use our Search by Model Tool below to find an Alpine Chain Co. Hardwood-Optimized replacement chain for your exact Stihl, Husqvarna, or Makita saw, dispatched daily from our warehouse.