My wife's been using her road bike for commuting so it's taking rather a lot of winter road abuse. The rear mech has stopped rotating properly forwards/backwards meaning that the jockey wheel ends up miles away from the cassette or she gets really slack chains. PITA.
Have tried some no-brand penetrating lube and some Muc-Off Bike spray to loosen (along with lots of wiggling) but it's still really sluggish.
Any other suggestions for getting this to move properly? Could the bolt that it rotates around be worn and need replacing?