Poulan Pro 18-Inch vs. 20-Inch (Sizing Guide)
Choose the 18-inch bar if it is approved for your exact Poulan Pro model and gives enough reach for your usual cuts. Choose a 20-inch bar only when the saw is approved for it and its power suits the work. The longer bar adds reach, not guaranteed cutting capacity. Check the manual, bar, and chain before buying.
If you are comparing Poulan Pro saws by bar length, the numbers can look like a simple upgrade: 20 inches reaches farther than 18. But the right choice depends on more than reach. Your saw’s engine, approved bar and chain, the wood you cut, and your ability to control the saw all matter.
I start a comparison by checking the model number, not the product-page headline. Poulan Pro model names can be similar, while approved parts and specifications may differ. A bar that fits physically is not automatically a suitable or approved match.
What changes between an 18-inch and 20-inch bar?
An 18-inch or 20-inch bar is the guide bar’s nominal length. The longer bar can reach farther into a cut, but it also changes handling and places more demand on the saw. Neither length alone tells you the largest safe cut the saw can make.
For a fair comparison, hold the saw model and task constant. A 20-inch bar can be useful where extra reach is needed, but it does not turn a smaller saw into a more powerful one. If the engine struggles, the chain is dull, or the wood pinches the bar, extra length will not solve the problem.
An 18-inch bar is often the more manageable option when it meets the task. It gives less reach, but can reduce leverage and make the saw easier to position. A shorter bar does not remove kickback risk, and a longer bar does not prevent it.
| Factor | 18-inch setup | 20-inch setup |
|---|---|---|
| Reach | Less reach into a cut | More reach into a cut |
| Handling | Often easier to position | Can be more demanding to control |
| Power needs | Depends on the saw and cut | Needs an approved, adequately powered saw |
| Best reason to choose it | Your routine cuts fit within its reach | You need the extra reach and the manual approves it |
| Main caution | Do not force it through an oversized or pinched cut | More reach does not mean unlimited cutting capacity |
Key takeaway: Choose based on approved fit and the cuts you actually make, not on bar length as a stand-alone performance rating.
Which Poulan Pro models accept each bar length?
A bar is compatible only when its mount and chain match the exact saw. Check the model and serial label, the owner’s manual, and the markings on the current bar. Do not assume that a bar listed for one Poulan Pro family fits another.
Parts listings commonly show PP4218-family configurations with an 18-inch bar and a chain using 3/8-inch low-profile pitch, .050-inch gauge, and 62 drive links. PP5020-family 20-inch configurations are commonly listed with the same pitch and gauge, but 70 drive links. Treat these as examples to verify, not a fit guarantee for every saw carrying a similar name.
Pitch is the spacing between chain rivets. Gauge is the thickness of the drive links that sit in the bar groove. Drive-link count is the number of links that engage the sprocket and bar. All must match, as must the bar-mount pattern.
| Check before ordering | What to confirm |
|---|---|
| Saw identity | Exact model and serial number on the saw |
| Bar approval | Length and bar-mount pattern listed for that model |
| Chain pitch | Must match the bar and sprocket |
| Chain gauge | Must match the bar groove |
| Drive-link count | Must match the bar length and setup |
| Replacement part | Compare the bar and chain markings with the manual or parts information |
If a listing gives only “fits Poulan Pro 18-inch” or “fits 20-inch,” that is not enough information to confirm a safe match. Compare the full specifications and ask the manufacturer or a qualified parts supplier if they do not line up.
Which length suits your cutting work?
Start with the wood and the cut, then check whether your saw is approved for the needed setup. Cutting conditions vary with species, wood condition, diameter, support, and tension in the wood. There is no universal rule that assigns a certain engine size or wood hardness to an 18- or 20-inch bar.
For pruning, bucking smaller logs, and general cleanup, an 18-inch setup may be a sensible choice if it reaches the cuts you need and is approved for your saw. For larger material, the 20-inch option may offer useful reach, but only if the model’s manual allows it and the saw can work without being forced.
Bucking means cutting a felled stem or log into shorter sections. The bar length does not tell you whether a cut is safe. Before each cut, consider how the wood is supported and where compression and tension may close on the bar. A trapped bar can create a hazardous situation with either length.
| Your typical work | Starting point | What to verify |
|---|---|---|
| Small limbs and routine cleanup | 18 inches may be enough | Approved fit; safe positioning and reach |
| Firewood-sized logs | Compare the actual cuts you make | Wood support, pinch risk, sharp chain, saw capability |
| Larger logs or more reach | Consider 20 inches only if approved | Manual approval and controlled handling |
| Occasional cuts beyond your setup | Do not force the saw or cut | Reassess the method and get qualified help if needed |
A common comparison I see is a buyer choosing 20 inches because some cuts seem close to the reach of an 18-inch bar. I would first ask whether those cuts are routine and whether the exact saw is approved for the longer setup. If not, the extra bar length may add handling demands without being a sound upgrade.
Equipment Setup and Safety Preparation
Before cutting, check that the saw, bar, chain, and safety parts are in working order. Follow the manual for your exact model, because fuel mix, starting steps, adjustment values, and approved equipment can differ. A correct setup supports control; it does not replace training or a careful plan.
Wear a helmet, eye and hearing protection, chainsaw leg protection, gloves, and suitable boots. Inspect the chain brake, throttle lockout, chain catcher, handles, bar, and fuel and oil caps. Check chain tension as directed in the manual, and make sure the chain moves freely when the brake is released.
Use only a bar and chain combination approved for the saw. Keep the bar-and-chain oil reservoir filled with dedicated chainsaw oil, then check oil delivery using the manufacturer’s procedure. Oil flow varies with the model, temperature, and oil; there is no single universal flow rate for all Poulan Pro saws.
For two-stroke fuel, use the ratio specified in your saw’s manual and follow the oil maker’s directions. Many Poulan Pro two-stroke manuals specify 40:1, or 3.2 US fluid ounces of two-cycle oil per US gallon of gasoline. Do not assume that ratio applies to every model. Use fresh fuel mixed correctly.
Start the saw on stable ground using the model’s stated cold- or warm-start procedure, with the chain brake engaged. Check that the chain does not move at idle and test the brake as directed. If the chain moves at idle, or a safety part does not work as intended, stop and consult the manual or a qualified service provider.
Field Cutting and Landscaping Operation
Good cutting practice matters more than the extra two inches of bar. Plan the cut before starting, keep a stable stance and two-handed grip, and keep the bar nose clear of objects. Do not cut above shoulder height or force a dull, loose, or mismatched chain through wood.
Rotational kickback can happen when the upper part of the bar nose contacts wood or another object. The saw can move rapidly upward and back toward the operator. A longer bar does not prevent kickback; its added reach can make control more demanding. Avoid nose-first cuts, use low-kickback equipment and a working chain brake, and follow the manual’s safe-work guidance.
For a tree or large limb, assess lean, dead limbs, wind, slope, overhead hazards, and escape routes. Establish an exclusion zone and a clear escape path. Felling needs a site-appropriate plan, a controlled notch, and sound hinge wood. Do not improvise hinge dimensions or fell beyond your training. ANSI Z133 provides safety practices for arboricultural operations; OSHA 1910.266 applies to covered logging work.
| Setup scenario | Decision process |
|---|---|
| Routine cleanup with smaller wood | Use the shorter approved setup if it reaches the cut with control |
| A log nearly as wide as the bar | Reassess support, cut plan, and saw capability; do not treat bar length as a safe diameter limit |
| Wood that may pinch the bar | Plan for compression and tension before cutting; stop if the bar begins to bind |
| A job requiring felling near hazards | Pause and assess the site, training, and escape route; bar length alone cannot make the job safe |
Do not force either setup through a cut. If the chain slows, the bar binds, or the saw behaves differently than expected, stop and reassess rather than pressing harder.
Maintenance, Sharpening, and Tuning
A sharp, correctly tensioned chain helps the saw cut as designed. Follow the chain maker’s sharpening instructions and use the specified depth-gauge setting. Depth gauges, sometimes called rakers, control how much wood each cutter takes. A .025-inch (0.635 mm) setting is a common reference for many consumer chains, but it is not universal.
Use the correct depth-gauge tool and lower rakers gradually and evenly. Incorrect depth can affect cutting and increase risk. Inspect the bar groove, oil hole, rails, chain, and brake; clean debris from the clutch cover and air intake. Replace damaged parts and recheck tension after fitting or sharpening the chain.
Idle speed, maximum governed RPM, carburetor settings, and fastener torque are model-specific. Do not adjust the carburetor by ear or use a generic torque figure for bar or clutch fasteners. Use the service manual and its tachometer procedure where required. If you cannot verify the adjustment, use qualified service.
Storage and Seasonal Care
Safe storage protects the saw and helps keep the bar and chain ready for the next job. Follow the owner’s manual for fuel storage, cooling, cleaning, and seasonal preparation. After work, engage the brake, switch off the engine, and let it cool before refueling or servicing.
Clean the air intake, clutch cover, bar groove, and oil hole. Inspect the chain and bar rails, sharpen or replace damaged parts, and check chain tension. Store the saw and fuel as the manual directs, away from heat and ignition sources.
How to make the final choice
The safest buying decision starts with a model-specific check. If both lengths are approved, choose the 18-inch bar when it reaches your usual work and you value easier positioning. Consider 20 inches when you need the added reach and the saw’s manual approves the complete setup.
Before you order, confirm the exact saw model, approved bar mount, chain pitch, gauge, and drive-link count. Then compare the tasks you do most often with the saw’s capability. If the manual or parts listing does not confirm compatibility, do not guess.
FAQ: Poulan Pro 18-inch and 20-inch bars
Is a 20-inch bar better than an 18-inch bar on a Poulan Pro saw?
Not by itself. It offers more reach, but the exact saw must be approved for it and able to handle the work. The longer setup can be more demanding to control.
Can I put a 20-inch bar on any Poulan Pro chainsaw?
No. Check the exact model’s manual and approved parts information. Bar mount, chain pitch, gauge, and drive-link count must all match.
Will an 18-inch bar cut an 18-inch log?
Bar length alone does not set a safe cutting limit. Wood support, cut method, saw capability, and the chance of pinching all matter. Follow the manual and do not force a cut.
What chain fits a PP4218-family 18-inch setup?
Common listings show 3/8-inch low-profile pitch, .050-inch gauge, and 62 drive links. Verify the exact saw and bar markings before buying.
What chain fits a PP5020-family 20-inch setup?
Common listings show 3/8-inch low-profile pitch, .050-inch gauge, and 70 drive links. Check the model label, manual, and bar stamping before ordering.
Does a 20-inch bar make a saw more powerful?
No. The bar adds reach, not engine power. A longer bar does not make an underpowered saw suitable for harder or larger cuts.
Can I use the same chain on the 18-inch and 20-inch bars?
Usually not if the drive-link counts differ. Chain length, pitch, and gauge must match the specific bar and sprocket.
What fuel mix should I use?
Use the ratio listed in the manual for your exact engine. Many Poulan Pro two-stroke manuals specify 40:1, but do not assume that applies to every model.
(This article was written by one of our staff writers, Marcus Thorne. Visit our Meet the Team page.)
