I’ve fitted and adjusted front mechs before, it should be a 30 minute job tops but I must have spent 3 1/2 hours trying to adjust a Deore M591 front mech with a Deore shifter and I feel like tearing my hair out (for the record the rear one set up perfectly just as expected).

The front mech. is the right height and parallel to the chainrings and the limit screws are set too. First off if was jumping from the granny ring to the big ring on the first click, then it would work spot on (for no apparent reason). Now it’s shifting up and down the rings correctly but when the chain’s in the middle ring the inner plate of the mech. is rubbing the chain in all gears (which would suggest that the cable tension is way too high, except it’s not and in the other two rings everything seems fine). I’ve tried new cables and I’m starting to wonder whether the shifter is dodgy.

I’m a novice mechanic for sure, but it’s not as if I haven’t successfully fitted mechs. several times before. Any ideas?

I’m going to give it a break and try again tomorrow.

Which way does the cable come from and how are you routing it round the mech?

The cable runs down the seattube (top pull) and simply wraps around the fixing bolt (under a washer) as shown in the instructions (I was going to link to the online instruction, but the Shimano tech. docs area seems to be experiencing problems).

What’s so odd was that it went from not working correctly to working correctly and then off again.

Eliminate all other issues – make sure the cable is new, the inner new and lube it very well. A small bit of friction in the cable will cause all sorts of problems.

Make sure the routing is good, no kinks or sharp bends.

I’ll have a play tomorrow. The shifters certainly felt stiff, but lighter to the touch when things were working correctly, I’ve no idea why though. The routing look fine but I’ll check it out again and perhaps give it a squirt of GT85. The inners and outers are new, the outers were bought from Merlin as Shimano gear outers but are unmarked (Shimano outers are usually marked SIS etc.) and they seem a little narrower in diameter than I’m used to (the ferrules are rather loose on it). Having said that I used the same stuff for the rear mech. which is working as expected.

Well it’s certainly got me baffled, but I’ll persevere and see where that gets me. The cable seems to run freely when I feed it through the outer and the shifter appears to work smoothly too moving the cable without effort. The front mech’s easy to move with finger pressure but once the cable’s attached to the mech (and I’ve checked again that it’s connected correctly) The shifter becomes very stiff and the problems commence!

Is the outer cable the right length? I’ve found it can sometimes make quite a lot of difference.

It looks fine but if I can’t get it sorted I’ll have to look at a new outer and perhaps trying different routing, although there are no sharp bends or kinks. Like I said, it’s not as if I haven’t done this before without problems so I’m a bit confused. With any luck I’ll get it sorted in the end.

Well, bonkers as it sounds, a new plastic ferrule at the shifter end and it’s as sweet as a nut and behaving exactly as expected! I’ve no idea why that should have made a difference but it does appear to have done just that! The outer had a quick squirt of GT85 too.

It’s just a shame I wasted a whole afternoon fiddling with something that should have taken 20-30 minutes.