If I swap-on a 16", or 14", bar & chain onto my 42cc / 18"-OEM-bar chainaw, will I have a significant cut-power boost?

I've been reading about everything related to chainsaws that I can find (and youtubing, especially Steve's Saloon series!) but haven't found a solid answer to this yet... If you're very very comfortable with a powerhead that came OEM with an 18" bar, but you never ever plan to use the thing in a manner that'd require >14" bar, wouldn't you get a serious power-boost by using the 14" bar (relative to the 18")?

Thanks for any answers/explanations on this one, am aware my 18" accommodates 14" and 16" bars (with specific drive-links at least) and wanting to down-grade the bar size (as I need more than this 18"s 42cc powerhead for my biggest saw) and just kinda hoping it's worthwhile to make the downgrade (instead of just buying another 18" chain for it, despite never using it on stuff over 1-2' wide!)

Also curious what type of chain(s) would be the most-aggressive that I could get, have read Oregon's manual and while it describes them it doesn't really say "this is the strongest"...I know I don't want a 'safety chain' (cut-link as every-other-link on the chain) but past that am unsure where to aim, bar/sprocket are generic 3/8" / 0.050"...actually I have a 14" with bad powerhead, may do some comparison-testing if the drive-links & pitch & gauge are appropriate for my 42cc's sprocket!

  • You should split your second question into a separate post. One a time around these parts. :) – isherwood Jul 8 '19 at 17:57

No. Or yes.

It isn't like gearing. A shorter chain doesn't compound torque like a smaller gear does. The amount of force applied at any point on the chain is identical.

However, the shorter bar limits how much contact the chain can make with the wood. Herein lies the difference. If you're cutting 16" of wood rather than 18" the motor isn't working as hard.

Should you do it? Probably not. You needlessly restrict yourself with respect to reach, and you can accomplish the same goal by working in a less aggressive manner when you're dealing with maximum-depth cuts.

  • 1
    I agree it will have the same power but a longer contact area, I have multiple bars for my saws but usually use the shortest I can for the job if I need a monster I pull out the big saw and run a 36” to a 28” bar , if a smaller job I use a smaller saw with an 18-24” bar and limb jobs 12”. By having the correct bar length I am using a lighter saw for the job than taking out my big saw. A longer bar can work if the chain is the same pitch / style but with a larger number of teeth you may jam the saw more often in the wood but it will work. – Ed Beal Jul 8 '19 at 18:13

Having done this with many chainsaws over the years (Danarm, Stihl, Husquvarna), the power from the engine gets shared between the number of teeth doing the cutting as well as the drive sprocket / chain losses and the chain / bar friction.

Then you need to consider the type of teeth - some are designed to better handle harder woods like oak and other teeth profiles designed for more resinous woods.

So, you have to have extra chains to deal with what you face. On a bad day we would go through 3 or 4 chains - only need one small stone stuck in the bark and the chain needed resharpening - quicker to fit a spare chain and continue. Then sharpen the chains in the evening...

  • I am cutting Live Oak as the most-frequent tree I encounter, it's the predominate species in my area of FL, how should I factor that into bar&chain choice? Most of my saws (all?) have the 0.050" gauge, 3/8" or 3/8"low-profile (for top-handled units) chains on 6 (IIRC, maybe it was 7?) toothed sprockets, get feeling that they're all interchangeable.. – guestposter1818181 Sep 3 '19 at 16:08

Reducing the bar size reduces the the surface area of the chain. This decreases the load on the engine/motor of the saw from bar drag, cut surface size, and inertial mass of the chain itself. A skip chain can also reduce drag on the motor by reducing the inertial mass, and the number of cutting links engaged in the wood. Both have the effect of making your saw more peppy, and in my experience cutting faster. The majority of consumer saws use bar size as a selling point. They are usually sold with a bar length near the limit of their capability. Reducing the bar length puts the saw more within the sweet spot of the saws capability. I do this with all my saws, and it works great.


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