as title really been thinking about it and am noy quite sure and how adjuster shifter to only go the 2 rings not 3, cant find a shimano 9spd double front shifter anywhere
I have mine adjusted so the first position is for granny ring, 2nd position is for the lower half of the cassette and the 3rd position is for the upper half. Means you can have the derailleur cage closer to the chain for the gears you'd use going downhill so the chain's less likely to fall off the inside 🙂
Just wind down the H screw to stop it shifting to the largest ring and it will only give you the the granny and middle to choowe from. You might find that you need a larger middle ring to cover the dropping the big ring
+1 craig, no adjustment needed other than limit screw stopping you using last click to big ring.
Having said that I've lowered mine so it sits closer to the bash (which is smaller than the big ring it replaced), so it acts a little like a chain guide and theres no way the chain can go up and over the bash.