Chainsaw Chain Installed Backwards? How to Tell and Fix It

A chain fitted backwards runs but hardly cuts. It is easy to do when fitting a new chain, easy to check, and the fix takes a few minutes. The steps are the same on battery, corded and gas saws.

How to tell

Look at the cutters on the top of the bar. The sharp cutting edge of each cutter should face forward, toward the bar nose, so it leads into the wood as the chain runs out along the top. If the cutting edges on top face back toward the saw, the chain is backwards. (On the underside of the bar they face the other way — that’s normal, because the chain loops around.)

On top of the bar the chain runs toward the nose, and each cutter’s cutting edge leads in that direction.

Symptoms of a backwards chain:

• fine dust instead of chips;
• the saw doesn’t pull itself into the wood, so you have to push;
• a brand-new or freshly sharpened chain cuts worse than the old one;
• smoke or heat from the bar after a short cut.

A dull chain gives the same symptoms. Oregon and STIHL both describe fine sawdust and having to force the saw as signs of a dull chain (Oregon manual, p. 11, STIHL Sharp Advice, p. 13) — so check direction first, then sharpness.

How to fix it

Remove the battery, unplug a corded saw, or switch off a gas saw and disconnect the spark plug wire. Wear gloves.

1. Loosen the bar nuts or side-cover knob and back off the tensioner.
2. Remove the side cover, lift the chain off the drive sprocket and out of the bar groove.
3. Turn the chain over so the top cutters will face the bar nose.
4. Fit it around the drive sprocket first, then feed the drive links into the bar groove all the way around to the nose.
5. Make sure the tensioner pin (if your saw has one) sits in the hole in the bar, then refit the cover finger-tight.
6. Tension the chain. STIHL’s method: hold the bar nose up and turn the adjuster until the chain moves freely by hand without binding; when you lift the chain at the middle of the top of the bar, the drive links should stay in the groove. Tighten the bar nuts while still holding the nose up, then check again (STIHL Sharp Advice, p. 11). Saws with tool-free tensioners have their own steps in the manual.

Check before you cut again

• Heat damage. If the chain ran backwards for long, look for blue discoloration on the bar rails; Oregon says blued rails have overheated and the bar and chain should be replaced (Oregon manual, p. 95). If you find no damage, the chain can go back into service.
• Oil. Confirm oil is reaching the chain — see bar oil not flowing.
• The right chain. A chain can face the right way and still be wrong for the bar. Check pitch, gauge and drive-link count against the bar — see how to read them.

On a test cut, a correctly fitted sharp chain should pull itself into the wood with light pressure and throw chips, not dust. If it doesn’t, check sharpness and the chain wear limits.

Sources

• STIHL USA — Sharp Advice for chain saw owners (PDF): tensioning saw chain (p. 11), sharpening saw chain (p. 13)
• Oregon — Safety & Maintenance Manual (PDF): cutting tips (p. 11), guide bar troubleshooting (p. 95)

Checked against these sources on October 1, 2026.