In America, we generally equate bigger with better and more powerful. This is especially true in the chainsaw department. Most chainsaw models you pick up from the hardware store will have a much larger chainsaw bar than the engine size requires. These large guide bars give the impression of more powerful cuts, but it may lead to an imbalanced chainsaw that is nose heavy and a reduced chain speed.
When it comes time to purchase a replacement bar for your chainsaw model, you might want to consider a shorter-size bar and a shorter chain. Whether this will increase your engine power or results in better cuts will depend on many factors. This article will help you understand if reducing the inch bar length of your guide bars is best for you.
Can a Chainsaw Bar be Replaced with a Shorter Blade?
Guide bar lengths can be adjusted to make your machine more adept at the specific tasks you need it for. In most cases, chainsaws are sold with the largest blade; the chainsaw’s engine can operate safely, and the features are designed to protect the user from a blade that size. It is usually possible to find a bar one or two sizes smaller than the standard one but make sure it is the same type of bar as your current blade, or you may need to replace more parts.
When replacing a chainsaw bar, the drive links, drive sprocket, chain size, chain gauge, and chain groove all need to match up correctly, or else the machine may not operate to its fullest capabilities. If the drive links or chain slips or can’t gain enough tension, then the blade will not cut through wood effectively. Each part can be adjusted or replaced to make sure your chainsaw is perfectly compatible with all its pieces.
When doing chain replacement, the chain size and pitch must be correct for it to tighten properly and to avoid slipping or snagging in use. Chain segments can be removed, and a safety chain can be added to further increase chain speed and reduce the friction of chain on wood. The guide bar and chainsaw chains must sit on the metal bar posts snugly and align with the oil nipple to receive proper lubrication, or else problems may arise during extended operation.
Why Do Chainsaws have Different-Sized Bars?
Allowing different inch bars on the same chainsaw model helps make a single machine more capable of tackling diverse tasks. A chainsaw may have the engine power to cut through very thick logs, but the stock blade is too short to create enough space in the cut to go through with ease. Changing the blade for one several inches longer can help you make shorter work of big jobs without needing to lug around a larger saw.
Most manufacturers offer 3 different bar sizes for their chainsaw models. Typically chainsaw blades are either small, medium, or large and range from 12 to over 40 inches long. Chains are sold in complementary sizes but may need some adjustments if they are not from an identical brand.
Being able to adjust your chainsaw with different-sized blades can help you find a replacement even when your current blade’s size isn’t available. If the configuration you need is not in stock, you can reduce the inch bar number a few sizes and get the parts for that size. Even when resources are scarce, you will have the opportunity to fit your saw with an appropriate cutting blade.
Benefits of Running Larger and Smaller Bars
The main reason to adjust the length of your chainsaw bar is for a higher chain speed, to balance a nose-heavy saw, and to better cut through larger hardwood material. Being able to change the blade of your chainsaw on the fly can help tremendously when working on cutting up logs of varying thicknesses a good distance from your workshop.
In general, running large and smaller blades can help you find the perfect 3:1 to 4:1 ratio of engine displacement (in cc) to bar length (in inches), so your machine can chop firewood much more accurately and quickly. It is also possible that your chainsaw has a light engine and a heavy blade which can lead to unintentional biting if you get tired or sloppy. Putting a lighter (shorter) blade on can keep the chainsaw from dipping when you cut through the thick logs.
| Bar Length | Benefit | Drawback |
| Short 12-20 inches | Faster Speed | Less control through bigger branches |
| Medium 21-30 inches | Good speed and balance | Burns through fuel faster |
| Large 31+ inches | Keeps cuts in larger logs open | Slower blade speed and potential overheating |
Short Bars
Short bars generally have the fastest torque and the least friction and allow your engine to operate for longer stretches of time without overheating or snagging. The shorter bars greatly reduce the weight of a chainsaw and can help prevent fatigue from kicking in early. The amount of time it takes a shorter blade to cut through thinner materials is far less than trying to handle smaller logs with a longer blade.
Shorter blades may need chain and sprocket adjustments, as most store models are fitted with the parts to run larger blades. It can be difficult to find stock of high-quality, branded short guide bars as most available are subpar-quality Chinese parts. The reduced nose radius of a shorter blade can increase the effort needed and blunt chains when cutting larger and harder wood.
Medium Bars
These medium-sized bars offer a good measure of blade reach and cutting speed without compromising on power. These blades can overheat and burn through fuel more quickly than the shorter blades when pushed hard into the wood. It is important to keep medium-sized chains sharp to prevent the need to rock the blade to make deep cuts.
If a medium bar is at the higher end of the capacity of your engine, you can consider a skip chain which allows more links without teeth between ripping teeth. A race chain offers the opposite effect and has more cutting teeth to shred through logs faster. Increasing and decreasing friction through the number of teeth contacting wood per rotation can give you the most control over your chainsaw cuts and preserve your machine’s longevity.
Large Bars
These are commonly the default chainsaw blades for chainsaws with powerful engines. These blades may look big and impressive, but they also require more fuel, longer chains, more lubrication, and use more energy to wield for long jobs. The cost of running your machine goes up the larger your blade size is, and the increased costs do not necessarily equate to more efficient cuts.
When it comes to felling trees, splitting large logs, or sectioning large windfall debris, large chainsaw bars with power chains are the way to go. While these have a definite time and place, constantly using the largest blade your chainsaw can handle may reduce the lifetime of the machine and take more of your time to maintain and tune-up. A large blade can also be heavy and unwieldy, potentially leading to dangerous situations and fatal accidents.
Steps to Safely Change a Chainsaw Bar
Changing a chainsaw bar is important for good machine maintenance and also to use your saw for a different task. Having the ability to switch blade sizes increases the usefulness of a home chainsaw, but proper care must be taken to do the job correctly. An improperly installed chainsaw blade could damage internal components or even present health hazards to the operator. The steps below can help you plan how to change your blade.
Remove Old Bar
When changing a chainsaw guide bar, you will want to remove the side panel and the nuts and bolts holding the bar in place. Make sure everything is loose, and then remove any components that are holding the bar in place. Lubrication build-up, wood debris, and chain shavings can all hold a guide bar in place and can be dislodged with a firm tug or smack.
Place all the pieces that will be going back into the saw off to the side and completely remove the blade from the sprocket. Clean all crude from around the sprocket, metal pins, and drive links before continuing on and replacing other components.
Change the Sprocket
If the chainsaw guide bar you are installing is either larger or smaller than the existing sprocket can support, you will need to replace those parts as well. A larger bar will need greater space between the gears of the sprocket and the chain groove. A smaller blade can get away with less space and better gaps and will need a smaller sprocket to accommodate that.
Follow the manufacturer’s instructions to replace the stock drive sprocket with one that is the right size for the new blade. Doing this much maintenance in the field is difficult so try to find a guide bar set that all uses the same sprocket to avoid excess work and maintenance.
Change Guide Bar
Now it is time to replace the guide bar with the correct size for the job and other chainsaw pieces. Make sure the bar is designed to install on your model of a chainsaw, or else some bolts and fasteners may not line up correctly. Check the pitch and gauge numbers and match them with the chain and sprocket you will be using.
Line the bar up with the screws and slide the end between the metal posts to hold it firmly in place. Hold the bar by the nose and pull it as far forward as the fastener will allow, and then tighten the nuts securely. Check to make sure the parts all fit snuggly together, and there is no friction on internal pieces.
Change/Adjust Chain
Chain maintenance may be required if a new chain fitting the bar is not purchased. In most cases, chains will have a little give, and when shortening the bar, you may find that the tension screw cannot lock the chain properly. If this happens, some adjustments need to be made.
It is easy to remove a link or two from a chainsaw chain to help create a tighter connection. For the best results, try to find the matching chain brand for your chainsaw bar to make sure it is compatible and not measuring incorrectly. Different chain patterns can work better on different bars, so try a few if you can’t find the exact match.
Adjust Depth Gauges
The part of the chain that grabs the wood and rips it off the log is adjusted using depth gauges. The deeper the gauge, the more wood is ripped each time a link contacts it, while the shallower gauges take less wood and reduce overall friction. You can adjust the gauges with a file to make any chain ideal for the task it is assigned to.
Chains on shorter bars will be spinning quickly, and deeper grooves will slow it down and take larger chunks out of the wood. Ripping more wood with each pass speeds up wood cutting and reduces the fine sawdust from binding up the blades. Longer blades should have shallower grooves that take less wood with each pass but also bring finer dust and less friction per cut.
Sharpen Blade Teeth
When the chain has been properly attached, gauged, and tightened, it is the perfect time to sharpen the teeth of the chainsaw. Dull teeth can lead to overheating, jammed chains, and more effort per cut. There are several ways to sharpen chainsaw teeth.
Using angle grinder disks or special files, sharpen and adjust the teeth and chain groove until it fits perfectly in its track and cuts perfectly. Repeatedly sharpening blades will also prevent smoking and keep wood cuts cleaner. when the cutting effort becomes much greater than before, check chains to see if they need to be re-sharpened.
Lubricate the Chain
When everything is attached and the blades and chains are all adjusted, it is a good idea to lubricate the chain and internal parts. During the bar change, the oil nipple may have been removed, and it needs to be replaced correctly. When adding oil to the chain, make sure lubrication covers every part of it completely.
If you are working in cool conditions, use a thinner oil that will not seize up in cold weather. If you are working in the summer, then a tackier oil that will stay on the chainsaw and not fly all over the forest is crucial. Mixing different SAE-rated oils can help you find the perfect lubrication for your saw and climate and ensure maximum cutting with minimal effort.
Danger: Improper blade length adjustment and installation could be life-threatening. Always use extreme care or consult a professional if unsure how to proceed.