I got a Stihl MS260 as a present that came with a 12"(0.325) bar guide and chain setup. I would like to upgrade it to 18"(3/8). Will this upgrade require a sprocket change?

Chainsaw-modding noob here, please educate me! I'm a little confused with the information available in the interwebs. Thank you!

  • 1
    You may get a better answer on diy.stackexchange.com . They have many chainsaw modding questions there.
    – Chenmunka
    Commented Nov 16, 2023 at 19:57

2 Answers 2


You can go to an 18 inch bar.

If you want to change pitch (chain link length between rivets) from 0.325 to 0.375 (3/8") you will need a new sprocket of that pitch as well. Think "gears not meshing" for a mismatch of chain and sprocket pitch.

Or you could go 18" and 0.325 and not need a sprocket change.

When I search for MS260 bars, the Stihl site comes up with nothing, well, one vague option that's not available, oddly, and other sites offer 16, 18, 20 and 24 inches, all in 0.325 pitch.

As far as I can make out from the manual that comes up only in German, .325, .404, 3/8 and 1/4 are all supported pitches.

This arborist site discussion mostly suggests sticking to 0.325 (it's not a particularly big motor. 3/8 chain cuts more wood into sawdust, making more work for the motor.) 3/8 (0.375) is the pitch being longer than 0.325, but it comes with a wider chisel tooth and thicker chain, so more kerf, meaning more sawdust per cut.

  • That utterly useless bar/chain selector tool also comes up with nothing useful for my saw. Which came with an 18" bar...
    – Ecnerwal
    Commented Nov 17, 2023 at 14:59

I had to check before I replied. The MS260 is available with 18inch bar guide. I was worried that you might be overloading the motor.

I don't know about this model, but I had a much larger beast and it didn't require a sprocket change when I went for a larger bar guide.

You could email/phone/visit a Stihl agent and ask that question, if you want to be 100% sure.

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