So I've not cycled in a while but my step dad was using my bike and he has a habbit of breaking stuff. I have since decided to start cycling to work again and I replaced various parts due to rust etc (Chain, Cassette, brake pads, cables) and seeing as they didn't work properly in the first place I decided to take some time to tune the gears. Now I think I understand them but the issue I have is: On the cassette at the back the gears will happily and smoothly shift from 7 to 1 under load or not under load. But going from 1-7 it will ignore me when I switch to 2 but when I then go 2-3 it will skip over 2 and onto 3.
So the question is: Why does it work perfectly from 7-1 under any load but then under any load it will not go 1-2 but every other gear works? It's literally that 1 down to 2 that won't work.
Please take note that there is no grinding noise or anything when i flick from 1-2 it quite literally just ignores me and makes 100% no attempt to switch but it happily jumps over 2 to 3 when I flick down to 3.