Originally Posted by
Kontact
I don't think there is a way to route the cable at the derailleur to make it too hard to move. It can make it not move far enough, or make it move too far.
Regardless, the problem appears to be happening at the derailleur. Not at the cable run along the frame or in the shifter, so the OP needs to find the manual for the derailleur to make sure they have it adjusted correctly and that the derailleur is oiled and has no obvious damage. A couple of drips of fine oil goes a long way.
Yes there is. If you move the cable routing over the tab, you increase leverage making it easier to operate the shifter. If you route the cable under the tab, it increases shifter effort and at a certain point the angle to the shifting arm on the derailleur changes to the point where no amount of effort will move the derailleur any farther. The OP could provide a picture of the cable routing on the shifter arm to verify this. Wish they would