What Messenger and Windthrown can't seem to understand is the 290 can't overcome the extra load of a wider chain and larger sprocket in hard wood. Go cut some Oak or Hickory with both setups and you'll see what we mean. And that's why Stihl specs offer both setups.
:bang: :bang: :bang: 3/8 chain runs better for me on a 290. Plain and simple. In Oregon White Oak, Pacific Madrone, Bigleaf Maple, and several other hard-ass woods. I will put Pacific Madrone up against ANY hickory or other dense wood that you guys have out there, wherever you are. It compares to eastern hickory in density and strength. We have more than just pansy-ass sofwood out here in the PNW. I ran a lot of tests on chains and saws over four years when I managed an 85 acre tree stand with mixed western and some eastern tree species. I also salvaged and cut a lot of firewood (10-20 cords a year) from slash piles and windthrow (where I got my user ID here). I thinned, felled and bucked up thousands of trees. For the first 2 years there, I used mostly a 290, with 20 inch bars and RM full comp chain, 3/8 and .325.
Two reasons I believe that 3/8 works better than .325. The first is that there are more cutters per inch in .325 than on 3/8 chain. In fact, .325 has 12% more cutters than 3/8 chain. As for 3/8 chain being wider, comparing the cutting widths, I do not notice any difference between standard 3/8 and standard .325 chain width. Comparing my Stihl semi-chisel 3/8 to my Stihl semi-chisel .325 right here, side by side, they are almost the same width from outer cutting edge to outer cutting edge. So I do not get this notion that 3/8 chain has the extra loading? I believe its the other way around, and due to having more cutters per inch, its the .325 that sucks up more torque.
The second reason I mentioned before that y'all gaffaw at is that the .325 does not cut as stright. The .325 bars pinch on me far more often than with either standard or picco 3/8 chain. I also noticed that most used .325 bars out there have an abnormal amount of paint worn off of them, far more than used 3/8 bars. Hell, one .325 bar I have has no paint left on it at all. Gone. Similar to many used .325 bars I have seen. So its 3/8 for me on all my saws, not just the 290. Standard 3/8 on my larger saws, and low profile 3/8 on my smaller ones.
BTW: This argument is about
standard .325 bars and chains, not NK. I tried to find NK .325 for my Stihls and posted queries here on AS some time ago, and it seems that the .325 NK stuff does not exist for Stihl saws. As for why Stihl offers .325 and 3/8 for the 290, I do not know. Why they offer 0.063 and 0.050 bars and chains defys me as well. I use mainly 0.050 3/8 bars and chain, but the Stihl .325 is all 0.063. Maybe its a European or east coast thing, like using short bars. Go figure.