Loose or misaligned bike chain
The bike chain slipping off when changing gears is likely caused by chain slack, misalignment of derailleur or chainring, or worn components. Adjusting chain tension, indexing the gears, and inspecting wear can help fix this issue.
Every step has an illustration. Follow the written instructions and safety notes as your guide.
Take it one step at a time
Repair steps
Inspect chain wear and length
Use a chain checker tool to measure wear; if stretched or damaged, replace the chain with one compatible to your bike type.
Check derailleur alignment
Ensure the front and rear derailleurs are properly aligned and not bent. Adjust derailleur hanger and limit screws as needed.
Adjust chain tension
For bikes with multiple gears, make fine adjustments to the rear derailleur tension using the barrel adjuster for smooth shifting and to prevent chain slipping off.
Clean and lubricate the chain
Remove dirt and debris from the chain and gears, then apply lubricant to reduce friction and wear.
Test shifting
Shift through all gears slowly to check if the chain stays properly on the chainrings and cogs.
