Stihl 009 Chain Replacement (Sizing Guide)
To replace a STIHL 009 chain, match the chain to the bar and sprocket actually fitted: check pitch, gauge, and drive-link count, then confirm the bar mount when ordering. Many 009 setups use 3/8-inch Picco chain, but that is not enough to identify a fit. Do not order by bar length or saw model alone.
A dull chain can burn wood, slow the cut, and make you push harder. An empty oil tank or a replacement chain that does not fit can stop the job before it starts. The fix is a short, careful check of the parts on your saw, not a guess based on the 009 name.
I start by reading the bar markings and counting the old chain’s drive links. Those details matter because a 009 may have a replacement bar or sprocket that differs from its original setup. The guide below shows how to identify the right chain, fit it, and check the saw before cutting.
What determines the right STIHL 009 chain?
A replacement chain must match three chain measurements and the saw’s fitted parts: pitch, gauge, and drive-link count. The guide bar must also fit the saw, and the chain must work with the drive sprocket. Confirm all of these before buying; a shared bar length does not mean two chains are interchangeable.
Pitch, gauge, and drive links
Pitch is the chain’s size class, based on the spacing of its links. Gauge is the thickness of the drive links that sit inside the bar groove. Drive-link count is the number of links that run through the bar and around the sprocket. Each must match the installed setup.
| Check | What it tells you | How to verify it |
|---|---|---|
| Pitch | Whether chain links fit the sprocket and bar system | Read the bar stamp and sprocket marking; confirm with the maker |
| Gauge | Whether drive links fit the bar groove | Read the bar stamp or manual; do not infer from saw model |
| Drive-link count | Whether chain length fits the bar and chain path | Count the old chain’s drive links and check the bar maker’s chart |
| Bar mount | Whether the bar fits the saw | Check the bar part information and confirm compatibility |
Many STIHL 009 setups use 3/8-inch Picco, also called 3/8-inch low-profile. That is a common configuration, not a guaranteed specification for every saw or replacement bar. Gauge can also differ; do not assume .043-inch or .050-inch without checking.
The bar’s usable markings may show pitch, gauge, and a recommended chain length or link count. If markings are worn or missing, use the bar’s part number and contact a STIHL dealer or the bar manufacturer. The takeaway: identify the fitted parts first, then order by the full specification.
How to identify the chain before ordering
Identification means checking the parts on your saw rather than relying on a model listing or an old receipt. A 009 may have had its bar, sprocket, or other components replaced over time. Use the existing setup as evidence, but confirm that it is sound and compatible before copying its measurements.
With the saw off, cool, and the spark-plug boot removed, inspect the guide bar. Look for stamped information near the bar’s mounting end. Write down the bar maker, part number, pitch, and gauge if visible. Check the sprocket marking or part number as well, since pitch must match the chain drive system.
Next, count the old chain’s drive links. These are the small tabs on the underside of the chain that sit in the bar groove. Count each one around the loop. Do not count cutters or side links. If the chain is badly damaged or missing links, use the bar maker’s chain chart and verify the bar and sprocket details with a dealer.
Before ordering, compare your notes against the chain and bar makers’ specifications. Confirm that the bar mount fits the 009 and that the sprocket supports the chain pitch. If the bar and sprocket do not match, buying a chain to fit one part can leave the whole setup incompatible.
| What you find | Next step |
|---|---|
| Bar markings are clear and parts appear sound | Match pitch, gauge, and drive-link count to the bar maker’s chart |
| Bar markings are worn or absent | Identify the bar by its part number or ask the bar maker or dealer |
| Old chain is stretched, damaged, or incomplete | Do not rely on its count alone; confirm the correct count from the bar chart |
| Bar, chain, or sprocket markings disagree | Stop and confirm a compatible setup before ordering |
A chain that leaves the bar at speed can cause severe injury. A wrong pitch or gauge, incorrect link count, poor tension, or worn bar or sprocket can contribute to derailment. If you cannot confirm a match, do not run the saw until you have checked the parts.
Choosing the replacement and the right file
The correct replacement is the chain maker’s model that matches the bar and sprocket, not simply a chain labeled for a STIHL 009. Chain models can differ in cutter shape and sharpening directions. File size, filing angle, and depth-gauge setting must come from the exact chain model’s instructions.
Do not use a remembered file size or angle as a substitute for the chain’s identification. Find the chain model number on the packaging or product markings, then check its sharpening chart. If the chain is already on the saw, its markings may help identify it; a dealer can also match the chain using your bar and sprocket information.
A depth gauge is the small part ahead of each cutter that controls how much wood the cutter takes. Its setting is chain-specific. If it is too high, the chain may cut poorly; if altered without the maker’s limits, it can make cutting more aggressive and less controlled. Use the specified gauge tool and instructions.
For a replacement, check that the package lists the exact pitch, gauge, and drive-link count, and that your bar and sprocket accept that chain. Keep the package or model details for future sharpening. The practical rule is simple: sharpen to the chain model, not to a generic 009 setting.
Fitting the chain and checking tension
Tension is the amount of slack in the chain around the bar. Correct tension keeps drive links seated while allowing the chain to move by hand when the saw is off. Follow the operator’s manual for the exact adjustment method; tension changes as the chain warms and wears.
- Put on suitable gloves and eye protection. Turn the saw off, let it cool, and remove the spark-plug boot.
- Confirm again that the chain’s pitch, gauge, and drive-link count match the bar and sprocket.
- Loosen the bar nuts as directed by the manual. Fit the chain so the cutters on the top of the bar face forward, toward the bar nose.
- Seat the drive links in the sprocket and bar groove. Refit the cover and adjust tension using the saw’s specified procedure.
- Tighten the bar nuts as directed. Check that the chain sits in the groove, moves by hand with a gloved hand, and does not sag beneath the bar.
Never inspect or adjust a moving chain. If a chain will not seat, feels unusually tight, or hangs loose despite adjustment, stop and check for a wrong link count, wrong gauge, damaged bar, worn sprocket, or incorrect assembly. Replace damaged or mismatched parts as a compatible set when the makers require it.
Common fit-check scenarios
These examples show how I would sort out typical replacement questions. They are decision examples, not claims about a particular owner’s saw. In each case, the markings and maker’s chart decide the fit; the 009 badge does not override them.
- The bar says 3/8 Picco, but the chain box lists another pitch. Do not install it. Find a chain with the bar’s pitch that also matches the sprocket.
- Pitch matches, but gauge is unknown. Do not assume the chain will fit. Read the bar specification or identify its part number before buying.
- The chain fits the groove but appears too long or short. Recount drive links and check the bar maker’s chart. Also inspect the sprocket and bar for wear.
- The old chain fits, but the bar has no readable marks. Use the bar part number or consult the bar manufacturer or a dealer. Do not treat the old chain as proof of a correct setup if parts may have been changed.
Oil, fuel, and the first check before cutting
Chain oil lubricates the bar and chain while they move. Fill the oil tank with bar-and-chain oil, then use the operator’s manual to verify that oil reaches the chain. If it does not, stop the saw and find the cause before cutting; there is no single flow rate that applies to every setup and condition.
Fuel mix is the gasoline-to-two-stroke-oil ratio specified for that saw, model year, and oil. Do not assume a modern ratio applies to every older 009. Check the operator’s manual or STIHL service information for your exact saw and oil. Do not run straight gasoline or guess a ratio.
Before starting, inspect the chain brake, throttle lockout, stop switch, chain catcher, bar, sprocket, and chain. Wear chainsaw-rated leg protection, a helmet with face and eye protection, hearing protection, gloves, and suitable boots. Clear bystanders from the work zone, check footing, and plan escape paths. Follow applicable ANSI Z133 requirements and, where relevant, OSHA 29 CFR 1910.266.
Start the saw using its manual’s cold- or warm-start steps on stable ground, with the chain brake engaged. Check brake operation and oil delivery before cutting. Use only the model-specific idle and carburetor settings in the service data. Do not tune by ear or exceed service limits; incorrect tuning can damage the engine.
During cutting, keep two hands on the saw, maintain secure footing, and keep the saw below shoulder height. Avoid contact with the bar nose, which can trigger kickback. Do not force a dull or binding chain. For tree work, use trained personnel and suitable arboricultural procedures; a chain sizing guide is not a felling plan.
After the first operation, stop the saw, engage the brake, and let the chain stop. Allow the saw to cool, then recheck tension and adjust as the manual directs. Clean the bar groove and oil hole, inspect the rails and sprocket, and rotate or replace the bar as its maker instructs.
Conclusion and quick answers
A reliable replacement starts with the installed bar and sprocket, not the saw model or bar length alone. Match pitch, gauge, and drive-link count, confirm the mount, and use the chain maker’s sharpening directions. Before cutting, verify safe tension, chain lubrication, and the correct fuel mix for your specific 009.
Frequently asked questions
What chain fits a STIHL 009?
The chain must match the fitted bar and sprocket in pitch, gauge, and drive-link count. Many setups use 3/8-inch Picco, but verify your parts before ordering.
Can I choose a chain by bar length alone?
No. Bar length does not confirm pitch, gauge, or drive-link count. Read the bar specifications and check the bar maker’s chain chart.
Does every STIHL 009 use .043-inch gauge?
No. Gauge depends on the installed bar and chain setup. Read the bar marking or identify its part number.
How do I count drive links?
Count the small tabs on the underside of the chain that sit in the bar groove. Do not count cutters or side links.
What file size does a 009 chain need?
The file size depends on the exact chain model, not just the saw. Check the chain maker’s sharpening chart for file size, filing angle, and depth-gauge setting.
What fuel mix should I use?
Use the ratio specified in the operator’s manual or service information for your exact saw and oil. Do not assume a newer STIHL ratio applies.
Can I use a chain with the right pitch but a different gauge?
No. The gauge must match the bar groove. A mismatch can prevent correct seating and create a dangerous setup.
Why does the new chain sag under the bar?
Check the drive-link count, adjustment, and condition of the bar and sprocket. Do not cut until the chain seats and tensions according to the manual.
What should I do if the chain does not oil?
Stop the saw. Check the oil supply and bar oil path according to the manual, and do not cut until oil delivery is confirmed.
Should I retension a moving chain?
No. Shut the saw off, engage the brake, and wait for the chain to stop. Make all checks and adjustments with the engine off.
(This article was written by one of our staff writers, David Hensley. Visit our Meet the Team page.)
