Comparison of Rim & Drum drive to Spur Sprocket drive system

[Jim Spencer]

I am thinking that the Rim & Drum would be an improvement over the Spur Sprocket and yet if it were an improvement why don't the chainsaw manufacturers use it?

Is the Rim a smoother drive?
Does the Rim support the chain better than the spur sprocket?
Does anyone know or think they know? 
Being a retired engineer and having used a chainsaw for at least 50 years I have a tendency to think the rim is an improvement but things are not always what they seem to be on the surface.
I have a Stihl 066 which I use on a Logosol Mill which I changed to a Rim & Drum and   still don't know if it is an improvement.
Please jump in and add your 2 cents to this question.
Maybe there were some tests done which were used to develop the rim system?

Jim

[sawguy21]

The rim is cheaper to replace when worn and is easy to change chain pitch or tooth count. The spur sprocket is cheaper for the manufacturer and is used primarily on lower priced consumer saws that don't see as much use.

[sawmilllawyer]

Have to agree withSawguy21 there.

[olyman]

The rim is cheaper to replace when worn and is easy to change chain pitch or tooth count. The spur sprocket is cheaper for the manufacturer and is used primarily on lower priced consumer saws that don't see as much use.

ya think---the original sprocket on the 090 stihl is rim--guess what you get from stihl now???? spur--cause they are cheaper to make--and--they sell more of them--because you replace it all when the spur is shot---before--just replace the 2.50 rim-------sprocket now is 47 clams---!!!!!

[sawguy21]

Spur on an 090 ??? I would look at Oregon or Carlton.

[limbrat]

My little ps510 came with a spur. I jumped the chain off a few times while limbing, changed to a rim no more problems since. My 7900 came with a rim.

[snowman]

Worst thing about spur sprockets on bigger hi revolution saws is that when you throw a chain they tend to bugger up your drivers, sometimes beyond repair.Not that I ever throw my chain. :D

[olyman]

Spur on an 090 ??? I would look at Oregon or Carlton.

 spurs are  available----and the guy that sold the last of his old stock rim drives on ebay--got good money for em!!!!!!!!!!!!!!!

[Ax- man]

Rim sprockets are the way to go on saws, they are easier to change out when it is time to replace them, plus a rim will line the chain up to the bar for better alinement (sp) for smoother cutting and less wear and tear on the  drivers .

[oldsaw]

A rim is the ONLY way to go.  Finally found one to fit the Super XL...at a price I wanted to pay.

Rims last longer, are cheaper to replace, and "adjustable" since you can often run a tooth larger or smaller to fit the need.  On my 066, I run a 7 or 8 tooth depending on what's on the list that day.  The 8 tooth gets you a bit more chain speed in the smaller stuff so you can finish quicker.

Just go with the flow.  Spurs just plain suck, and they cost to much money.  I'm a legendary cheapskate.

Mark

[olyman]

cheapskate or no , old--the dang co's that make the sprockets refuse to do what the owners want--rim drives---cause they want excessive profits--spur drive--clowns--

[joe_indi]

Don't think the spur sprocket has no place on a high power saw.The spur sprocket has one advantage over the rim sprocket viz. it can run both old chains and new ones without the risk of the chain snapping.An old rim sprocket and a new chain are not the best of combinations as there is a mis-matched seating problem between the drive links and the rim sprocket.The spur on the other hand does not have this problem.
It would be advisable to have spur sprocket and a solid nose bar handy when you install a new chain.Let the chain run in for a couple of hours and then switch back to the rim sprocket .
This will save you a bit on broken  chains.