If I have the front mech high enough to clear the middle ring when shifting into the larger it is too high for the lowest ring. When in the lowest ring the chain rubs on the bottom slip plate on the front mech.
I have seen chainsets sold with this combination - so why am I doing wrong?
I do not have a smaller middle or larger small chainring.
I'm running 22 32 44 at the moment without any issues whatsoever. I'm using a deore top pull if that matters??? What mech, chainset, bike is this on?
Was the front mech new, & did it have the clearance sticker on it to aid setup (assuming shimano)? From memory, when the derailleur swings over to the big ring, the outside edge only has about 1mm clearance from the teeth as it passes.
chainset is a square taper job, front mech a deore one with the clamp lower than the swingarm to fit in the FS Marin - Oh the shame 
- frame.
If I set it up so that it just clears the big ring (as sticker indicates) the middle ring rubs the underside of the swingarm when in large ring.
the middle ring rubs the underside of the swingarm when in large ring.
The outer plate should just clear the big ring by a few mm when shifting up to the outer ring. Are the hi-lo screws adjusted properly ? I always set front mechs with no chain on, & by hand at first. Park Tools guides are usually very good.
If I set it up so that the inner plate clears the middle ring, the bit between the inner and outer plate, I'm calling it the lower skid plate rubs on the chain, indicating the mech is too high, I lower so the chain is very slightly above the skid plate when undertension and the mech shift up to large ring, but middle ring teeth are hitting underside of inner plate.
I agree I should set up without chain and cable first.
Obviously,if you're running a larger middle ring, then you may need to run the mech slightly higher to avoid the inner cage touching it.If the chain then drags on the bottom of the cage when in granny, what gear is it in when this happens?I suspect it's only happening in the smaller sprockets at the rear,a gear combination you shouldn't be using for various reasons inc.the one you've mentioned.If it is, then don't run those gears, and don't worry about it.
also as its a FS frame, when you sit on it, the suspension should "sag"
this should lower the bb/raise the axle hight and stop the rubbing.
hope that fixes the problem
I think oneoneoneoneoneone has it...my last full sus would rub on the workstand but was fine when you rode it as long as the suspension had a little sag. Or the mech could be bent.
Thanks all, will build up , off workstand/ride and try.
set it up as normal (following all the little tabs.) then ride it.
I had exactly the same issue on my heckler, and no amount of fiddling got rid of it except running extra sag in the shock. I got cheesed off with teh noise of chain rubbing and poor gear change and just got a 32 tooth middle - problem solved!
I had a problem like this when I bought a new deore mech from merlin. I didn't realise when I bought it that front mechs have different chainstay to seat tube angle requirements. On looking I saw my new mech had an angle setting of 63 to 66 degrees whereas my old one was 66 to 69 degrees. Problem solved when I changed the mech. See here for more info
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