Hi, I have a gx 12 speed gear mech. When riding rough trails, my chain has developed a habit of bouncing off my lower Jockey wheel and runs between the cage and the Jockey wheel (I can still pedal - sometimes I don't even notice..).
Jockey wheels are in good condition with reasonably new bearings, chain has <0.5% wear, gear hanger is straight and the mech cage appears normal (not bent/deformed), gears well adjusted.
Nothing has changed on my bike, but the chain issue has started recently.
Any ideas?
Stiff chain link? Had similar recently and just one link was rusted enough inside to make it stop flowing nicely.
Check to see if the cage has worn.
They cut a groove in the inner face and it causes this as its then baggy enough to have the chain come off the teeth n wedge in there.
Check the mahusive torque on the crank bolt - if it gets loose it can cause jockey wheel/chain issues before you notice the wobbly crank.