3/8 lo pro and 3/8 sprocket differences?

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

B_Turner

Addicted to ArboristSite
Joined
Oct 6, 2006
Messages
3,136
Reaction score
423
Location
Renton, WA USA
I am fairly new to the 3/8 lo pro thing. I know it's been discussed, but I can't remember the answer.

Is 3/8 lo pro actually .365? Can I run 3/8 lo pro chain on a 3/8 sprocket?

Or 3/8 regular on a sprocket that came with lp originally?
 
I wouldn't mix them. Here is a pretty good thread on the issue.
http://www.arboristsite.com/showthread.php?t=39384&highlight=3/8+low+pro+full+size

I still come away a little befuddled. I can see not mixing the bars andbar sprockets between them, but the difference when it comes to drum sprocket vs floating rim is not quite clear to me.

I need to compare each chain on each of those sprockets and really look at how the tang fits each. Maybe then I'll understand a little better.

One reason I am thinking about comparing is that then I can compare cutting speed between certain small saws of mine using the same lp chain.
 
I wouldn't mix them. Here is a pretty good thread on the issue.
http://www.arboristsite.com/showthread.php?t=39384&highlight=3/8+low+pro+full+size
Ray,

That is a confusing thread, they are talking about 3/8, 3/8 lp, and 3/8 picco.

It was my understanding that picco is it's own beast, and because of such it does make sense that the tang is different on the chain, but doesn't regular 3/8 and 3/8 LP have the same tang on them?

Mathematically, the chain and sprocket/rim have to be the same, or it couldn't be 3/8" pitch. However, a different tang as on the picco chain, would render it a red headed step child.
 
I thought Picco was a Stihl-exclusive term for 3/8 LP. :confused:

One of my saws came with a LP chain on a 3/8 bar. Granted, it was a .058 bar, but that was the only mismatch. It operated just fine. Just bought a 3/8 .058 chain to replace it.

Shoot, even the drive link count is the same, isn't it?
 
Last edited:
3/8 lo pro is not the same as 3/8,the difference is slight.now with that being said I have seen plenty of saws run the 3/8 sprocket for the 3/8 lo pro application, but not the other way around.
 
I thought Picco was a Stihl-exclusive term for 3/8 LP. :confused:

One of my saws came with a LP chain on a 3/8 bar. Granted, it was a .058 bar, but that was the only mismatch. It operated just fine. Just bought a 3/8 .058 chain to replace it.

Shoot, even the drive link count is the same, isn't it?
I've been told that it is thinner material for the entire chassis.

The gent who taught me how to build with logs told me to avoid it at all costs...:rolleys:
 
Difference between both chains (I'm sure most are aware of this)...
20062009292.jpg

3/8"LP on a standard 3/8" nose sprocket (ie: BAD!)...
20062009295.jpg

Standard 3/8" on a 3/8"LP nose sprocket (ie: BAD!)...
20062009296.jpg

A standard 3/8" rim sprocket will drive a 3/8"LP chain (not sure about spur sprockets though), but best to get the bar for the job. I don't think the standard 3/8" tang will fit a LP sprocket but not sure - bit too deep I think?
 
Last edited:
Ray,

That is a confusing thread, they are talking about 3/8, 3/8 lp, and 3/8 picco.

It was my understanding that picco is it's own beast, and because of such it does make sense that the tang is different on the chain, but doesn't regular 3/8 and 3/8 LP have the same tang on them?

Mathematically, the chain and sprocket/rim have to be the same, or it couldn't be 3/8" pitch. However, a different tang as on the picco chain, would render it a red headed step child.

You got that wrong!
3/8 picco is Stihl lingo for 3/8 lp - no more, no less.

Remember that the pitch is measured at the rivets, not at the contact point between the drivers and the rim. As the contact point is closer to the rivets on the lp/Picco, they need a slightly larger diameter rim to run on.
 
I think this thread is making the difference more clear than I've seen before.

I could understand about the sprocket nose issues easily enough, but I think I get the differences between the chains where the tangs fit the drive sprockets a bit better now.

Next time I have a 3/8 lp drum sprocket off (which will be soon as I'm switching another saw to 1/4) I'll get out a 3/8 floating rim and each chain and really try to see how they each fit each drive.

Thanks.
 
You got that wrong!
3/8 picco is Stihl lingo for 3/8 lp - no more, no less.

Remember that the pitch is measured at the rivets, not at the contact point between the drivers and the rim. As the contact point is closer to the rivets on the lp/Picco, they need a slightly larger diameter rim to run on.
Troll,

Is it true that the thickness of the wall is thinner on the picco? That is what I have been told.
 
Difference between both chains (I'm sure most are aware of this)...
20062009292.jpg

3/8"LP on a standard 3/8" nose sprocket (ie: BAD!)...
20062009295.jpg

Standard 3/8" on a 3/8"LP nose sprocket (ie: BAD!)...
20062009296.jpg

A standard 3/8" rim sprocket will drive a 3/8"LP chain (not sure about spur sprockets though), but best to get the bar for the job. I don't think the standard 3/8" tang will fit a LP sprocket but not sure - bit too deep I think?

those pics show why my dealer calls standard 3/8, 3/8 large.... without any amount of timer fallers(pulp wood only), most dont need the large chains.... almost impossible to get 404 here....
 
My next thought.....

Do they make a bar that will interchange 3/8LP and 3/8 nose sprockets? I thought my 3/8 bar that had 3/8LP chain on it fit good at the nose. So good that I thought it was a .325 bar and chain, until I recognized .325 for the first time at a dealer.
 
I am pretty sure you will discover that all 3/8" chain (standard and LP) are really more like .365, the profile of the tooth and the drive link are different as as Troll points out require different configurations of the sprockets. We simply call them 3/8" since it seems close enough.

It may be possible to run a LP chain on a standard drive sprocket and vice versa, I guess I've never tried, at least that I was aware of.

I did find something interesting on one of my old saws with a 7/16" pitch chain and spur sprocket, .404 chain actually fit the sprocket better, correctly in fact. Believe it or not the .404 sprocket would drive the 7/16" (.4375")
pitch chain but I don't suppose it would last very long doing it.

Mark
 
I am pretty sure you will discover that all 3/8" chain (standard and LP) are really more like .365, the profile of the tooth and the drive link are different as as Troll points out require different configurations of the sprockets. We simply call them 3/8" since it seems close enough.
Mark

Thats right Mark, they are both really .365" - I checked this last time with my calipers after you mentioned it as I thought you may be wrong but alas...
I was :(
It is the size and shape of the drivelinks that are the reason they're not interchangeable.
3/8"LP nose sprockets have rounded teeth, standard 3/8" more pointed. Some guys on here have said that they can run standard 3/8" on a 3/8"LP bar but none of the bars I have in stock will interchange.
 
No, there just are some that call it that, to differentiate it from regular 3/8", that they call .375.

In reality the pitch of all chain called 3/8", .375 or .365
is .367
.

:givebeer:

Not fair Sawtroll, I only have a cheap set of calipers and .365" was close enough for me ;)
 

Latest posts

Back
Top