Stihl MS 251 24-Inch 60cm Bar (Fitment Guide)
A 60 cm (24 in) bar is not a routine approved fit for the STIHL MS 251. Do not install or use one unless STIHL confirms that exact bar-and-chain combination for your saw’s serial number and market. Fitment depends on more than bar length: mount, pitch, gauge, sprocket, nose, drive-link count, and approved bar range must all match.
Bar-length listings can vary by country and saw configuration, so a bar that looks compatible in a store listing may still be unsuitable for your powerhead. That mismatch matters: a longer bar adds weight and chain load, and can make a saw harder to control. I use the model-specific manual or confirmation from a STIHL dealer as the deciding check, not a retailer’s generic fitment chart.
Equipment Setup, Bar Fitment & Safety Preparation
A bar-and-chain combination is a matched set of parts, not a choice based on reach alone. For an MS 251, check the exact saw’s manual and markings before buying or fitting a bar. If STIHL does not approve the proposed 60 cm setup, stop there; matching the physical parts does not make the combination approved.
The MS 251 has a 45.6 cm³ engine, and STIHL publishes power of about 2.2 kW (3.0 bhp). Those figures describe the powerhead, not its approved bar range. A 24-inch bar exceeds commonly listed MS 251 fitments, so treat it as not approved unless STIHL confirms it for your saw’s serial number and market.
What must match before a bar can fit
A bar mount is the shape and slot pattern where the bar attaches to the powerhead. Chain pitch is the spacing between chain drive links; gauge is the thickness of those links. The sprocket, bar nose, and chain length must also suit the saw and each other. Confirm every item, not just the bar’s length.
Use this checklist when checking a proposed setup:
| Check | What to match | Where to confirm |
|---|---|---|
| Approved bar length | Bar must be within the range STIHL approves for your exact saw | Manual or STIHL dealer |
| Bar mount | Slot and oil-hole pattern must suit the powerhead | Bar markings and fitment information |
| Chain pitch | Must match the bar nose and drive sprocket | Bar, chain, and sprocket markings |
| Chain gauge | Must match the bar groove | Bar and chain markings |
| Drive-link count | Chain must be the correct length for the bar and sprocket | Chain packaging or chain markings |
| Sprocket | Must match the chain pitch and approved setup | Saw parts information or dealer |
Do not assume a specific pitch or gauge from an online listing. MS 251 configurations vary by market and bar option; for example, a 3/8-inch low-profile chain and .050-inch gauge should not be treated as universal. Read the markings on your actual bar and chain, then check them against the manual or dealer’s confirmation.
Fitment decision for a 60 cm bar
For a 24-inch bar, the decision is simple: if the exact combination is not expressly approved by STIHL for your MS 251, do not fit or operate it. A bar that attaches correctly can still exceed the approved setup or pair with the wrong chain. Physical fit is necessary, but it is not proof of safe or approved fitment.
This rule also avoids a common shopping trap: choosing a chain by bar length alone. Even if a chain’s drive-link count appears to match, the pitch, gauge, sprocket, bar nose, and approved bar-length range still need to agree. Ask the dealer to verify the entire combination, not just whether the bar mounts.
Field Cutting and Landscaping Operation
A correctly approved setup is only one part of safe cutting. Before starting, inspect the saw and work area, then use the bar and chain only within the manual’s instructions. A longer bar increases handling demands, and the bar tip needs particular care because contact at its upper side can cause kickback.
Before work, wear a properly fitted helmet with face and hearing protection, chainsaw chaps or trousers, gloves, and protective boots. Check the chain brake, throttle lockout, chain catcher, controls, chain tension, bar, and chain. Clear bystanders and obstacles, and plan an escape route. Assess tree lean, overhead hazards, and any suspended or loaded wood before cutting.
Start the saw on stable ground using the prescribed cold- or warm-start procedure, with the chain brake engaged. Keep both hands on the saw and maintain a stable stance. Do not let the bar nose touch a limb, trunk, or other object unintentionally. Contact at the upper quadrant of the nose can throw the saw back toward you.
Do not use a 24-inch bar as a workaround for poor access or a cut that is beyond the saw’s capacity. Choose an approved setup and plan cuts for the wood and the tool. Felling requires suitable training and compliance with applicable ANSI Z133 or OSHA requirements; use a qualified arborist for complex trees or hazardous conditions.
Illustrative fitment scenarios
These scenarios show how I would resolve common buyer questions. They are decision examples, not reports of specific customer jobs or proof that any particular 24-inch combination is approved.
| Situation | Fitment check | Appropriate decision |
|---|---|---|
| A 60 cm bar mounts, but its paperwork does not list the MS 251 | Mounting alone does not confirm approval, chain match, or operating suitability | Do not use it; ask STIHL to verify the exact combination |
| The bar is listed for an MS 251, but pitch or gauge markings differ from the saw’s setup | A mismatch can prevent correct chain engagement or operation | Do not mix parts; confirm the correct approved set |
| The saw’s manual lists a shorter setup, while an online seller suggests 24 inches | The manual is the model-specific reference; the seller’s generic listing may not cover your saw | Follow the manual unless STIHL confirms otherwise |
| The dealer confirms a bar-and-chain set for the serial number and market | Approval and the complete parts match have been checked | Install and operate only as instructed in the manual |
The practical takeaway is to make the fitment question specific: give the dealer the saw model, serial number, market, and the proposed bar and chain markings. A yes-or-no answer about “a 24-inch bar” without those details may not settle compatibility.
Maintenance, Chain Sharpening & Authorized Tuning
Maintenance cannot make an unapproved bar safe, but it helps keep an approved setup working as intended. Use the manual for chain tension, cleaning, oiling, sharpening, and engine settings. Do not compensate for a heavy cut by forcing a dull chain or changing carburetor settings beyond STIHL’s procedure.
A depth gauge is the part of a chain link that controls how much wood the cutter takes with each pass. Set it to the chain maker’s specification, not a generic value. For applicable STIHL 3/8-inch low-profile chains, the published setting is typically 0.65 mm (0.025 in); check the exact chain marking and instructions before filing.
Use suitable bar-and-chain oil and verify oil delivery using the manual’s procedure. There is no universal oil-flow rate that confirms every saw is working correctly. Follow the model manual for idle speed, maximum speed, and carburetor adjustment; do not tune by ear or apply generic RPM figures.
If the chain binds, cuts poorly, or appears to receive too little oil, stop and inspect the setup. Check chain sharpness and tension, bar groove and oil holes, and whether the chain and bar specifications match. If the problem remains, use a qualified STIHL dealer rather than continuing to cut or adjusting the carburetor without the prescribed method.
Shutdown, Cleaning & Seasonal Storage
After cutting, engage the chain brake and shut off the engine. Let the saw cool before cleaning or servicing it. Clearing debris from the bar groove, oil holes, and sprocket area helps you inspect wear and oil flow, while a final tension and damage check helps identify issues before the next use.
With the engine off and the saw cool, clean the powerhead and the bar and chain area. Remove sawdust and debris from the bar groove, oil holes, and sprocket area. Check the chain, bar, and controls for damage, and recheck chain tension according to the manual before storage or the next job.
For seasonal storage, follow STIHL’s instructions for fuel and saw storage. Use fresh, correctly mixed fuel when operating the saw. STIHL’s standard recommendation is a 50:1 fuel-to-oil ratio when using suitable STIHL two-stroke oil, but confirm the required mixture in your model’s manual and use fresh fuel.
Before putting the saw away, record the bar and chain markings if you have not already done so. That small step makes a later replacement easier to verify and reduces the risk of buying a part based only on the bar’s length.
Conclusion and Fitment FAQ
The safest answer is not to treat a 60 cm bar as an approved MS 251 upgrade. Confirm the complete bar-and-chain combination against the manual or with STIHL for your saw’s serial number and market. If STIHL does not expressly approve it, do not install or operate it; choose an approved setup instead.
Can I put a 24-inch bar on a STIHL MS 251?
Only if STIHL confirms that exact bar-and-chain combination for your saw’s serial number and market. Otherwise, do not install or use it.
Does a bar that physically fits mean it is approved?
No. The mount may fit while the bar length, chain, sprocket, or other specifications are unsuitable or unapproved.
What should I give a STIHL dealer to check fitment?
Give the dealer your MS 251 serial number and market, plus the proposed bar and chain markings. Ask them to verify the full combination.
Can I choose the chain by bar length alone?
No. Chain pitch, gauge, drive-link count, sprocket, and bar nose must match the saw and bar.
Does every MS 251 use the same pitch and gauge?
No. Configurations can vary by market and bar option. Check your actual parts and the model-specific manual.
Is 2.2 kW enough to prove a 24-inch bar is suitable?
No. The published power figure does not establish an approved bar range or prove that a particular chain setup is suitable.
What fuel mix should I use?
Follow the manual for your saw. STIHL’s standard recommendation is 50:1 with suitable STIHL two-stroke oil, but confirm the instruction for your model.
What should I do if the saw cuts poorly with an approved setup?
Stop and check chain sharpness and tension, bar condition, and oil delivery using the manual. Do not force a dull chain or make unapproved carburetor adjustments.
How do I reduce kickback risk?
Keep the bar nose clear of unintended contact, use a two-handed grip and stable stance, and follow the manual’s safety instructions. Nose contact at the upper quadrant can cause kickback.
Can a 24-inch bar replace training for a difficult cut?
No. Use an approved setup and suitable training. For complex or hazardous tree work, contact a qualified arborist.
(This article was written by one of our staff writers, Marcus Thorne. Visit our Meet the Team page.)
