I have a road bike with shimano front derailleur and dropped shifter. For weeks my front derailleur has been very stiff, requiring much force on the shifter to go onto the bigger ring, so the other day I decided to look inside the shifter. Presumably because of months of 'forcing' the shifter up a gear, the circular rotating bit of plastic which the end crimp of the gear cable slots into was pretty mashed up.
So I purchased a new shifter of the same make and model and installed it (new cable too), but shifting up a gear still takes a lot of force; actually, it doesn't shift at all now. I can move the derailleur directly with my finger and thumb, with what feels like not much effort - I say that with caution because I'm not sure how hard it should be to move it manually. But it moves smoothly at least.
I've clamped the cable to the derailleur, on the smallest rung, as tightly as I can but still no luck. Any ideas?