my rim sprocket on my 038 broke into three pieces today, has anyone had that happen before? which is more durable, rim sprocket or spur sprocket? why do some manufacturers use one and some use the other?
stihl rim sprocket
- Thread starter woodfarmer
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Lakeside53
Stihl Wrenching
woodfarmer said:
Rim floats with the chain and allows a more constant chain tension than with spur as the chain is always running in the "wear groves".
Unusual for a rim to break unless it was badly worn. The spec is 0.5mm wear, but most take it way beyond that point.
16gauge
ArboristSite Operative
In my limited experience, neither is longer lasting/durable, it is just much simpler and cheaper to replace a rim spocket. The clutch drum will eventually need replacement in either case. The real advantage of the rim type is as stated above.
Gypo Logger
Timber Baron
I've only had 3 rims break in 20 years that I can recall. Like was mention, wear may be the biggest factor.16gauge said:
Also the older rims had sawdust purging holes or scalloped on one side. This also weakened the rim. I think the newer rims are a solid piece design.
John
off to my stihl dealer monday morning, thanks for the input
smokechase II
Addicted to ArboristSite
The floating rim sprockets are a good product.
The spur type have a tendency to keep grabbing the chain when thrown and generally this causes more chain damage.
The spur type have a tendency to keep grabbing the chain when thrown and generally this causes more chain damage.
I am no pro and have now very big personal experience, but with several rim sprockets I had tensioning problems due to the ovality (rim diameter for the chain is not the same at any rotational angle) of rims especially with Oregon ones. This may be caused by the improper fusing of rim sides during their manufacturing or from little difference of rim pitch from chain pitch 
With spur (had used only one) there was no such problem, but was problem with chain throwing and bar excessive wearing at mounting end.
Usually manufacturers are classifying rim system pro and spur system for both, for occasional and pro usage.
With spur (had used only one) there was no such problem, but was problem with chain throwing and bar excessive wearing at mounting end.
Usually manufacturers are classifying rim system pro and spur system for both, for occasional and pro usage.
Diesel JD
ArboristSite Guru
I have the rim on my 025 and like it. I will have it on my MS390 when it needs a new sprocket. It's just so simple and cheap to repalce you can always have a good working sprocket on there. That being said, the 025 won't cut straight, but it has seen a lot of abuse. Think it is from other factors.
SawTroll
Information Collector
Pinus, are you sure that you did not try to use a regular small 7-spline Oregon sprocket on a Stihl mini spline?pinus said:
Oregon does not make sprockets for those mini splines, as far as I know.
Surely no. The Stihl/Oregon uncompatibility I learned in another way, when I used Orebon drum.SawTroll said:
The strong chain tension pulsation I got with Oregon drum+rim. Stihls rims were beter, but one had the small pulsation too
