# rim vs spur sprocket



## ac45 (Mar 5, 2003)

What are the advantages and disadvantages to both. I always seemed to prefer the rim sprocket from my experience.


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## mikek711 (Mar 5, 2003)

Cost.....Its a whole lot cheaper to swap out a rim sprocket when it wears out than to replace the whole clutch assembly when the spur is through........providing you are not buying the rim sprockets from the local dealer.......


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## jokers (Mar 5, 2003)

You can also give yourself a quick gear ratio change with a rim. Russ


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## glens (Mar 5, 2003)

Mike, I think you meant to replace the "clutch drum", and not the entire "clutch assembly" (which would include the clutch itself?).&nbsp; Even if one <i>does</i> opt to support their local dealer (yea!), the savings is still very real over the long run for a rim versus unitized spur/drum.

Another consideration is that the effective pitch diameter fluctuates on a spur (1.73" to 1.56" for 3/8&times;7) whereas it doesn't on a rim (which supports the chain on a circular pattern for a constant 1.67" pitch diameter @3/8&times;7).&nbsp; The fluctuating diameter change induces a "vibration" because of the constant increase and decrease in chain speed (7 such cycles per revolution of the crank in this example).&nbsp; It's part of why CV joints are used in front-wheel-drive cars and Harley Davidson uses a belt final drive.&nbsp; Admittedly, the vibration levels probably wouldn't be too noticeable using a chainsaw, but they're there nonetheless.

In conjunction with that last bit, the chain is better supported in it's travel around the sprocket on a rim.

Then there's the (hopefully rare) possibility of a thrown chain being influenced in unkind ways by spinning spurs (and vice versa) while a rim would be less likely to be "effective" that way.

There's also the matter Russ (jokers) brought up.

All in all, if it's possible to use rims, it's a good idea in my opinion.

Glen


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## formersawrep (Mar 5, 2003)

You did ask about the advantages of both, so....
The spur sprocket is cheaper to produce and MUCH more "idiotproof" to install the chain onto. These two factors make it the logical choice for homeowner type saws. 

The rim sprocket assembly is by far the better way to go for those who will use their saw a lot (most readers of this forum)


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## mikek711 (Mar 5, 2003)

Glens,
You know I was just ribbing a little about the dealer comment right?
Just checking,
Mike.


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## bwalker (Mar 5, 2003)

> Harley Davidson uses a belt final drive.


 I thought Harley guys liked motors that can dual function as a paint mixer.


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## Fish (Mar 5, 2003)

Being a "local" dealer, I charge the same amount for a rim and
spur sprocket at @ $27.95 American, and if they want the rim
sprocket "system", then that is another ballgame alltogether.

Installation is extra, of course.


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## spreaderman (Mar 5, 2003)

*sprocket type is a chain eater*

Also if the chain happens to come of while the spocket type is still spinning it can eat up the teeth in under you chain thus ruining it... with the rim type this won't happen...... I changed from the sprocket type to the rim type on my 023 today. I lone this saw out from time to time and thought this might add some chain security


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## Fish (Mar 5, 2003)

Dang Glen!
You are an interesting person. You must read some serious
literature when on the commode in the morning! You likely
have the full collection of 
Walt Galer's notes on the decadence in the chainsaw industry
in the mid 20th century, and his theorems on chip tragecteries
when making a racing chain, and taking them to the AS with
bold claims of superioriety. I know my spelling may be a little
weak tonight, as it is week 3 of ice storm '03, and the idiot
customers are wearing me down, and I do not care about
formalities anymore.
I could digress, but I won't, but I now hate any redneck with
a saw. Some customers have recognized my angst, and have
sent their good looking wives in with the saws to get them
repaired or sharpened. Even the ugly wives are prefferred
to the old rednecks.


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## Oregon_Rob (Mar 5, 2003)

Is it possible to convert a 009 to Rim? I popped a chain off a while back and messed up the chain and spur and it is still sitting there.


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## glens (Mar 5, 2003)

Sorry Fish.&nbsp; I've only seen a few of Walt's items here and rather wish he was still around 'cause it seemed awfully interesting.&nbsp; I would read through more of it, but other than the searchability of the setup here, these web-based forums are pretty maddening to use.&nbsp; If you dink around for a few minutes chasing a rabbit or something, you find your "session hash" cookie has expired.&nbsp; If you accept the new one you're offered three times per article if you don't, then you lose indication of and the ability to jump right to the first post you haven't read in a thread.&nbsp; But I digress... what was I saying?

I don't really read much about much of anything; I just look at a situation like this sprocket stuff and intuitively know it.&nbsp; It's a curse, believe me.&nbsp; I had MIT and Rose-Hulman, etc., courting me back when I didn't merely act like a teenager but blew them all off because I just wanted to be a partying redneck.&nbsp; In retrospect I should have done what Babcock done and got educated.&nbsp; Maybe I wouldn't have been so bitter now; but more importantly, I'd have some money...&nbsp; Maybe I could be swilling Bitburger instead of Miller.

But thanks, man.&nbsp; I think you're interesting too.

Ben, it's surprising how those paint-shakers jump into smoothness at working speed.

Oregon_Rob, I don't know about the oh,9.&nbsp; Have you looked in at http://www.oregonchain.com/index.htm?&nbsp; They have a product "assistant" through which you might find a favorable answer if you enable javascript.

Oh, Fish... never mind.&nbsp; I was going to ask you if you'd looked up the oil-pump thing but I did already.&nbsp; Wanna compare notes?&nbsp; So them boys took to sending their <s>sisters</s> wives in with the saws, huh?&nbsp; <s>By the way, how's the law work in Kentucky?&nbsp; If your folks get divorced, is your mom sill your aunt?&nbsp; :<i></i>)</s>

Glen


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## glens (Mar 5, 2003)

Dang!&nbsp; That white-out bled right through!&nbsp; Maybe I didn't shake it enough...


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## brncreeper (Mar 5, 2003)

Hey Glen, the “Delete” key is just below insert and just left of “End”


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## Fish (Mar 6, 2003)

OUCH!!

I am humbled...

I never have endured such tribulation until now.....

And during Lint....


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## Dennis (Mar 6, 2003)

Isn't lint what is in your belly button in the morning? 

I will take a 50mph Harley (paintshaker? I think you called them Glens) over a 150mph rice burner any day of the week.

Sisters? Wives? whats the difference in Kentucky?


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## treeclimber165 (Mar 6, 2003)

> _Originally posted by Oregon_Rob _
> *Is it possible to convert a 009 to Rim? I popped a chain off a while back and messed up the chain and spur and it is still sitting there. *


Never seen an 009 with a rim sprocket, but you can take the old sprocket and chain to your friendly (or not-so-friendly) dealer and buy a new sprocket and chain. Then throw the old ones away. They are trashed and should be thrown away so they do not end up back on a saw at some point in the future.

It seems most people like saving trashed chains, sprockets, bars, etc. I don't understand it. If they are bad enough to take off a saw, then they aren't going to 'heal' while sitting on a shelf for 5 years collecting dust. I'm not picking on you, Rob. I used to do it until I decided to toss all that old crap (most of which was for saws I no longer owned). Practically every tree guy I know has a couple bins or shelves full of crapped out parts 'just in case'.


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## Oregon_Rob (Mar 6, 2003)

*Scrap man!*

Hey, I resemble that remark! Actually I hadn’t gotten that far, but you are right, to the scrap metal pile they will go!


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## glens (Mar 7, 2003)

Dennis,

I would take the paintshaker too, these days.&nbsp; Well, maybe a Ducati...

Ben was the one that brought up the paint-shaking talk, but it's a perfect mental image.&nbsp; It's weird how they dance around like that at idle but become more still as they get to work.

That first-year V45 Honda Sabre I had was like a DC motor, but I divagate...

Oh, I stuck my head in the door of a Husky/Stihl dealer late this (now yester) afternoon.&nbsp; Imagine my surprise to learn that the 372XP will outcut an MS660!

Glen


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## jokers (Mar 7, 2003)

Well glens you shouldn`t be surprised, we`ve all known that for years! Russ


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