Do shorter bars cut faster?

[Analyst Man]

Being the curious type, I wonder if anyone has any hard facts about shorter bars cutting faster. Since the Linear speed of the chain can be no faster than the circular speed of the drive sprocket why do some say that a shorter bar cuts faster? True a shorter chain will make more revolutions per minute than a longer one, but the Linear speed is identical. To prove this, think of it this way. If you could tie your chainsaw to a bicycle (try not to laugh) and only have the drive sprocket portion of the chain touching the ground you would travel at the same speed regardless of the length of the chain. So, Is there that much more drag on a longer bar? Has anyone timed their cuts using the same saw on the same diameter log with different length bars?

 

[rbtree]

Short answer.....YES! Less surface area=less drag, resistance, friction = less power needed to maintain chain speed, which allows more down pressure to be applied= more cut speed. And less chain weight helps as well.

 

[blsnelling]

Within reason, I don't think you'll see a longer bar slow a saw down unless your using the extra length. If you're cutting the same size wood with both length B&Cs, I don't think you'd notice any measurable difference. However, I have never put this to the test with a stopwatch. I just can't imagine there being that much drag.

 

[Analyst Man]

Within reason, I don't think you'll see a longer bar slow a saw down unless your using the extra length. If you're cutting the same size wood with both length B&Cs, I don't think you'd notice any measurable difference. However, I have never put this to the test with a stopwatch. I just can't imagine there being that much drag.

“Using the extra length”, as in a 12 inch bar buried VS a 14 in bar buried, now that makes sense. And I agree that I can’t see the drag making that much difference either. Maybe someone will respond with some actual tests.

 

[belgian]

Short answer.....YES! Less surface area=less drag, resistance, friction = less power needed to maintain chain speed, which allows more down pressure to be applied= more cut speed. And less chain weight helps as well.

+1 ! That's why I am a fan of shorter bars in general. Not everybody faces the PNW wood style every day, especially in this part of the world.

the difference in saw performance between a short and long bar is very noticeable on solid tip bars (stihl duromatic, etc), less on roller tip bars.

 

[Analyst Man]

+1 ! That's why I am a fan of shorter bars in general. Not everybody faces the PNW wood style every day, especially in this part of the world.

the difference in saw performance between a short and long bar is very noticeable on solid tip bars (stihl duromatic, etc), less on roller tip bars.

Therein lies my dilemma. I can see a longer solid tip bar being a little slower than a shorter one when both are buried to the max, but what about on the same 8 inch log. And really the same principle applies to a sprocket tip.

 

[indiansprings]

I agree with Brad, I have never noticed a difference as long as the wood your cutting is the same diameter, at least with roller nose bars. Maybe the extra mass and weight/momentum of the longer chain negates any friction, within reason comparative length say 16" vs 25" not 16 vs 36.

 

[bitzer]

Unless you put a stopwatch to it you will not notice that much difference. That being said I timed a Stihl 310 (59cc) I ported with an 18" and 25" bar in 10" Basswood. The 18" averaged at 3.5 secs. The 25" at 6.5 secs. Both were brand new chains. I would say a lot also depends on the saw and torque. Obviously you can't get too crazy like compare a 16" to a 36", but the larger the saw the closer the times would get I would assume within reason. For everyday work I don't think it would matter that much unless you are in it for speed production. Therein also lies losses and gains that are negotiable. Longer bar= longer reach, safer distance for dangerous cutting, 3 cuts to fell a tree instead of 6, back saver, etc... Short bar=less teeth to sharpen and a bent back. For a work saw I would go longer. Certain applications where speed is the deal, shorter may make a difference.

 

[scotclayshooter]

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I think Timberwolf would be able to answer this

 

[belgian]

Therein lies my dilemma. I can see a longer solid tip bar being a little slower than a shorter one when both are buried to the max, but what about on the same 8 inch log. And really the same principle applies to a sprocket tip.

You will not notice it probably too much if your power head has power to spare during the work, but when its nominal power is consumed by the sawing department, the additional friction will slow it down, no doubt about it.
You don't see many hard tip bars on smaller saws, there's a reason probably.

 

[blsnelling]

I think Timberwolf would be able to answer this

The second log is much larger.

That being said I timed a Stihl 310 (59cc) I ported with an 18" and 25" bar in 10" Basswood. The 18" averaged at 3.5 secs. The 25" at 6.5 secs. Both were brand new chains.

There's some real world evidence. I'm surprised.

You will not notice it probably too much if your power head has power to spare during the work, but when its nominal power is consumed by the sawing department, the additional friction will slow it down, no doubt about it.

Makes sense to me.

 

[albert]

It probaly makes a bit of difference. Take a Ms 460 and set it @ 13,500 with a 24" b+c. Then tach it with a 16" and a 32".

 

[Analyst Man]

You will not notice it probably too much if your power head has power to spare during the work, but when its nominal power is consumed by the sawing department, the additional friction will slow it down, no doubt about it.
You don't see many hard tip bars on smaller saws, there's a reason probably.

Yes, “when its nominal power is consumed”, like when the entire bar is buried, but is the average schmuck like me going to notice the difference cutting a 6 inch oak log with a 14 inch bar VS a 16 inch bar? It’s probably the Tim Allen thing, but if there isn’t a noticeable difference I would think the longer bar to be the better choice.

 

[Paul001]

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I think Timberwolf would be able to answer this

I think that video answers the question rather pointedly

 

[Analyst Man]

It probaly makes a bit of difference. Take a Ms 460 and set it @ 13,500 with a 24" b+c. Then tach it with a 16" and a 32".

With a bar twice as long, yes I can see some drag making a difference there, but I’m talking about comments that I’ve seen where its suggested to go 2 inches shorter to speed up the cutting time.

 

[bitzer]

I think that video answers the question rather pointedly

Different sized woods with a smaller saw will make a big difference.

 

[2dogs]

If you are using two different bar lengths that are appropriate for a given saw then the shorter bar will cut only a bit faster due to less friction loss. lighter chain, etc. A short bar length for a saw will generally alloe for a larger drive sprocket. I run an 8 tooth sprocket on a MS441 with a 22" bar but I have to run a7 tooth when using a 25" bar. A larger sprocket means faster chain speed but lower chain torque.

 

[Analyst Man]

If you are using two different bar lengths that are appropriate for a given saw then the shorter bar will cut only a bit faster due to less friction loss. lighter chain, etc. A short bar length for a saw will generally alloe for a larger drive sprocket. I run an 8 tooth sprocket on a MS441 with a 22" bar but I have to run a7 tooth when using a 25" bar. A larger sprocket means faster chain speed but lower torque.

Ahhh, different sprocket size. That does make sense. I wasn’t aware that you can change the sprocket size on chainsaws. That would make a big difference.

 

[Paul001]

Different sized woods with a smaller saw will make a big difference.

Teach me not to pay attention. I assumed it was the same saw, different bars, on the same log...

 

[oldsaw]

With a bar twice as long, yes I can see some drag making a difference there, but I’m talking about comments that I’ve seen where its suggested to go 2 inches shorter to speed up the cutting time.

I don't imagine 2" is going to do much on that end. At that point, it's balance and handling. That being said, I really like 16" bars, with 20s being a close second. I like a 25" on the 066 (balance and explosive performance), but a 16 was an awful lot of fun, although gross overkill. needed a bigger sprocket.