Sometimes, we have already pressed the shifter, but the chain either can’t go up or down, or it goes up and down alternately. What should we do in this situation?
First, lower the chain to the smallest freewheel and flip down the rear derailleur damping switch, then flip it back up after adjusting the shifting.
Method 1: Check the small exposed section of the shift cable on the rear derailleur for bending or breakage. Replace it with a new one if issues are found.
Method 2: Replace the New Dropout
If your shifting system was smooth before and there are scratch marks on the rear derailleur one day, the dropout is likely deformed. A deformed dropout causes chain skipping and is hard to adjust with other methods. The dropout connects the frame and rear derailleur and deforms easily when the derailleur is hit/squeezed. Solution: buy and install a new dropout.
If your shifting system was smooth before and there are scratch marks on the rear derailleur one day, the dropout is likely deformed. A deformed dropout causes chain skipping and is hard to adjust with other methods. The dropout connects the frame and rear derailleur and deforms easily when the derailleur is hit/squeezed. Solution: buy and install a new dropout.
Method 3: Adjust the Rear Derailleur Limit Screws
Most rear derailleurs have three limit screws. The H/L screws prevent the chain from falling off the freewheel left/right:
Most rear derailleurs have three limit screws. The H/L screws prevent the chain from falling off the freewheel left/right:
- If the chain can’t reach the smallest freewheel, counterclockwise-turn the upper screw (avoid over-turning to prevent jams).
- If the chain can’t reach the largest freewheel, counterclockwise-turn the lower screw (avoid excessive turns to prevent leftward falls).
- The last screw adjusts the distance between the derailleur pulley and freewheel—usually untouched.
Method 4: Use the Shifter Knob to Improve Chain Skipping
Most shifters have an adjustment knob for shift cable tightness:
Most shifters have an adjustment knob for shift cable tightness:
- Chain won’t go up? Counterclockwise-turn to tighten the cable.
- Chain won’t go down? Clockwise-turn to loosen the cable.
Note: Lower the chain to the smallest freewheel first. Avoid over-turning—half a circle brings noticeable effects.
Method 5: Shorten the Chain!
If the first four methods fail, the chain is too long. Hang it on the largest chainring and freewheel (unthreaded through the derailleur). Two extra links = ideal length; cut off the rest.
If the first four methods fail, the chain is too long. Hang it on the largest chainring and freewheel (unthreaded through the derailleur). Two extra links = ideal length; cut off the rest.
