Any help gratefully appreciated as this used to shift sweetly.

It has been v hard to shift at the lever case since I changed the cable before Christmas. Finally had a look at it today thinking I’d have to replace the cable again but when you disconnect it the cable shifts v slickly. Also he derailleur swings smoothly and easily too, but connect them together and it feels like my thumb pressure will break the lever!

Cable does attach directly down though the groove I presume?
thanks

Check that the outer isn’t kinked anywhere. Also flush the outer with some GT85 in case it’s got shite in there.

connect them together and it feels like my thumb pressure will break the lever!

If it’s the Front Mech then it’s possible you’ve incorrectly routed the cable and are now pulling the Mech in the wrong direction?

If you have only changed the inner, the outer and/or the ferrules at each end may be knackered, or kinked as above

It’s rear derailleur and no kinks, the cable moves v smoothly when disconnected, as does the derailleur. Odd.

Have you clamped the cable the wrong side of the clamp bolt or similar?

I don’t think so but That’s what I’m wondering.

Cable comes from outer above and passes vertically down through gap on outside (facing slightly rear) part of derailleur arm where there is a grove and held in by plate that the allen bolt screws down. Pretty sure it’s right but there’s always scope for being a numpty.

Is it Shimano inner and outer cable?

It’s not actually – but if it’s running freely when disconnected why should that matter?

I think I’ll just bite the bullet I think and change the cable again.

Just make sure it’s SP41 outer and a Shimano inner (stainless as a minimum). The cable is an often overlooked component of the drivetrain that makes a surprising difference to function. Nobody does cables better than Shimano.

Are there any external cable guides such as under the BB? These sometimes snag when the cable is under tension and add significant friction.

Check your shifter. I had similar symptoms once, was flummoxed every time I tried to trouble shoot, eventually I lost the range of movement and gears so bit the bullet to replace the cable, but when I went to pull the cable out of the shifter (SRAM shifter) the cable didn’t want to come out easily. Took the cap off the shifter and it seems that a single cable strand had broken and the cable was unraveling inside the shifter and getting tangled up with all the mechanism. The cable looked fine and intact as it exited the shifter and was smooth down stream of the shifter. It was a real PITA to sort out as well as I had to disassemble the shifter due to the strand being entangled, which took me ages to re-assemble and get working properly.

Nobody does cables better than Shimano

Depends on the price point; the cheaper stuff is nothing special, whereas the polymer coated ones are pretty good.

I’ve had something similar on one of these multi pull direction mechs. Make sure the inner cable is following the correct path, they sometimes route in what looks like an odd direction.

[edit: note to self read the bloody thread title] 😳

Otsdr – I’d say that the Polymer cable is their weakest offering in terms of bang for buck. Good cable, but spendy and don’t last as long as the cheaper ones. Good solution for bikes with lousy routing as they run so slick.
At every price point, their cables work better than the alternatives in my experience.

Otsdr – I’d say that the Polymer cable is their weakest offering in terms of bang for buck. Good cable, but spendy and don’t last as long as the cheaper ones. Good solution for bikes with lousy routing as they run so slick.
At every price point, their cables work better than the alternatives in my experience.

Check for a broken ferrule or end of old one in cable stops?