# FS 80 to FS 85 upgrade?



## XSKIER (Jun 1, 2013)

Has anyone ever put the solid driveshaft of an FS85 in place of the flex drive shaft on an FS80? Is the drive tube the same? Does the FS 85 use carrier bearings?


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## XSKIER (Jun 1, 2013)

I've found out that it is possible to simply slip the FS85's solid driveshaft into the FS80's drive tube without modification. Now all I need to find out is if it will make the trimmer run $43 smoother?


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## Morganism (Jun 2, 2013)

Unless the flex cable drive is broken, why would you want to "upgrade" Plenty of saw blades have been installed on FS80s though it is beyond spec.


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## XSKIER (Jun 7, 2013)

Here is the results of my labor. It is quite apparent the increase in smoothness with a solid driveshaft. Total installation time: 3 minutes. Tools required: T-27 driver. 

[video=youtube;ZlDV51V0tVI]http://www.youtube.com/watch?v=ZlDV51V0tVI[/video]


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## Morganism (Jun 7, 2013)

I'm impressed. If my flex drive will ever snap, I will do this. :msp_biggrin:


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## ncpete (Jun 8, 2013)

impressive results!


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## XSKIER (Jun 10, 2013)

So I ran a tank of 50:1 90 oct E-free: HP Ultra through my FS 82.5 yesterday in some tall grass. The whole time running it I was thinking to myself that those folks at stihl really know their stuff. The trimmer is exactly $43 smoother, no more, no less. I was considering putting the $43 towards a new FS 130, but I just don't have enough tall grass trimming to justify the cost, besides already having a KM 130 R with a trimmer head and brush cutter head. I just thought I would wrap this thread up for those who may be considering the upgrade.


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