I've been running an XTR front mech and XTR crankset on my SWORKS Epic for over a year without problems and a year before that on an On-One ScandAL. Over that time the front mech has never missed a shift.
Just recently things went pear shaped and I was struggling to shift up from the middle ring to the big ring. On closer inspection I've discovered the front mech actually hits the inside of my driveside crank when I attempt to shift.
I tried adjusting the H stop screw to stop the mech being pushed out that far but then I can't get onto the big ring cleanly.
I've had a look at the mech and it doesn't look bent or feel loose. The only thing I can remember fettling with is the crankset which I had to remove and refit to fit a new middle ring about 4 months ago - but the problem has only started within the last month or two.
Has anybody suffered similar problems or can someone suggest a solution?
My hunch is I need a new mech but don't want to go splash cash on something if it isn't required.
cheers
Try putting your front mech up the frame a few mm hopefully this should sort it.Maybe ?
I have the same problem on my 08 Spesh stumpy FSR. The crank arm very slightly rubs the front mech when in the big ring. I have fiddled with the hi stop but then struggle to get the gear. It is anoying but i just live with it now as i cant see a way around it :0(
Pull the arm out and see if it is 3mm above the outer chainring - I agree with GSI that it sounds a bit like your front mech slipped down the seat tube? Also is there any wobble/play in the mech to suggest its failing?