Derailleur Adjustment Guide
The derailleur is a bike component that moves the chain from one cog to another when the shifter is used while a rider is pedaling.
If the cogs or chain are very dirty, grimy, or sticky, that can affect the bike's ability to shift properly. Check out the article and instructional video for how to perform basic bike chain cleaning HERE.
If the bike chain falls off the freewheel cogs, or the bike is noisy or imprecise when shifting, a derailleur adjustment is recommended.
You will need:
- Phillips head screwdriver
- A friend to hold the bike
- Get the bike ready for maintenance. Turn off the bike, remove the battery, and press MODE to discharge remaining power.
- Inspect the derailleur. Look at the derailleur, located at the rear wheel, and see if it's lined up directly below the gear that the shifter is set to. Note: When in 7th gear, the chain should be on the small cog. When in first gear, the chain should be on the largest cog.
If the derailleur or derailleur hanger is bent so it does not hang straight below a specific gear, take the bike to a local, certified, and reputable bike mechanic for repair, or contact Rad Power Bikes Product Support for help.
- Prop the bike so the rear wheel can spin freely. Have a friend hold the bike on the kickstand so the rear wheel is lifted off the ground.
- Click a heading below. Click on a heading below that best matches the issue you're having and follow the steps within the section to adjust the derailleur.
The Chain Falls off of the Freewheel
Problem: The derailleur is too close or too far from the freewheel.
Solution: Adjust the high and low limit screws.
Adjustment Steps:
- Locate and adjust the derailleur limit screws. Locate the limit screws at the back of the derailleur. The derailleur is marked with an H (higher limit) or an L (lower limit) near the screws. These are used to limit the range of the derailleur's movement on the freewheel gears.
- If the chain is falling off the smallest cog: Rotate the cranks forward and shift into 7th gear (the chain should be on the smallest cog). Use a Phillips head screwdriver to turn the higher limit screw clockwise to tighten, until the chain on the upper jockey wheel is aligned directly under the smallest cog.
- If the chain is falling off the largest cog: Rotate the cranks forward and shift into first gear (the chain should be on the largest cog). Use a Phillips head screwdriver to turn the lower limit screw clockwise to tighten. This will move the derailleur down the cassette. Turn until the chain on the upper jockey wheel is aligned directly underneath the large cog.
- Shift between all gears to test the alignment. Rotate the cranks forward with one hand and shift through the gears at the same time. Check to see if the derailleur moves the chain to each gear smoothly.
- Repeat the adjustment. Adjust the upper or lower limit screws until the chain no longer falls off the cogs.
If the issue is fixed, reinstall the battery and test the bike fully.
If the issue continues after adjusting the derailleur, consult a local, certified, and reputable bike mechanic or contact Rad Power Bikes Product Support.
Shifting is Noisy or the Chain Jumps Cogs
Problem: The shifter cable tension may be too tight.
Solution: Add slack to the shifter cable.
Adjustment Steps:
- Shift into gear 7. Rotate the cranks forward and shift into gear 7, which should place the chain on the smallest cog.
- Loosen the barrel adjuster on the derailleur. Turn the barrel adjuster on the derailleur clockwise, 1/2 to one full turn, to loosen.
- Shift between all gears to test the alignment. Rotate the cranks forward with one hand and shift through the gears at the same time. Check to see if the derailleur moves the chain to each gear smoothly.
- Repeat the adjustment. Turn the barrel adjuster clockwise, 1/2 to one full turn at a time, and test the shifting.
If the issue is fixed, reinstall the battery and test the bike fully.
If the issue continues after adjusting the derailleur, consult a local, certified, and reputable bike mechanic or contact Rad Power Bikes Product Support.
Chain Climbs Cogs Too Slowly
Problem: The shifter cable may be too loose.
Solution: Add shifter cable tension.
Adjustment Steps:
- Shift into gear 7. Rotate the cranks forward and shift into gear 7, which should place the chain on the smallest cog.
- Tighten the barrel adjuster on the derailleur. Turn the barrel adjuster on the derailleur counterclockwise 1/2 to one full turn.
- Shift between all gears to test the alignment. Rotate the cranks forward with one hand and shift through the gears at the same time. Check to see if the derailleur moves the chain to each gear smoothly.
- Repeat the adjustment. Turn the barrel adjuster counterclockwise, 1/2 to one full turn at a time, and test the shifting. Do not turn the barrel adjuster counterclockwise all the way or the adjuster will come out of the threaded hole.
If the issue is fixed, reinstall the battery and test the bike fully.
If the issue continues after adjusting the derailleur, consult a local, certified, and reputable bike mechanic or contact Rad Power Bikes Product Support.
If you are not confident in your ability to successfully and safely perform all steps, we recommend having the work performed by a local, certified, and reputable bike mechanic.