just wondered as im swapping to double bash from triple if i need to drop the front mech. i was just going to do the upper limit screw to stop it overshifting but wasnt sure if i had to move mech at all. i presume it would look a bit better lower down and out the way but is in needed.
thanks

I did

you should be able to drop it a bit and it will shift better, make sure it still clears the chainstay and the bash ring.

It's not possible on my bike (Pitch) so I left it alone and it's been fine.

Better still get an SLX front mech that's made for doubles. Cost next to nothing, like all front mechs last forever and it'll be perfect for the job. Simples.

The contours on the cage are designed to push the chain when changing and give it space to move from big to little sprockets without rubbing. So if you drop it they'll be in the wrong place and you'll have chain rub and bad shifting.

I got a 2 ring SLX mech as Hadge suggested. works for me

however, if you set the limit screw so it stops at the middle ring, you may find you don't need to move it down (or at least not much) as the mech moves downwards throughout its swing anyway. Plus watch the chainstay, as said

mixed bag lol cheers i will have a fiddle tomorrow. thanks all

leave it.

I left mine. I tried adjusting the limit screws but the screw doesn't have enough adjustment to be of any use (top swing XT mech)

+1 for what Big John said.

Assuming you've effectively increased the size of the "middle" ring (assuming 36T double), then the contours on the inner face of the front mech (that allow space to accomodate the full range of the cassette) will need to be higher if anything, rather than lower.

I found it best to set front mech height by positioning its widest point around the chain whilst in larger (formerly middle) chainring and lowest gear of cassette.
That was my experience anyway, for what its worth.

I did it with no shifting or rubbing problems.