How to Adjust Your Rear Derailleur
This tutorial will teach you to adjust your rear derailleur for the best shifting performance.
- Repair stand
- Small Phillips or Flat blade screwdriver
1. Place your bike in a repair stand if you have one, it will make the adjustment much easier. (You can always build a repair stand yourself.)
2. This is just like adjusting a front derailleur, the principles are the same. And we're assuming you have the cable hooked up. If not, go back and read about rear derailleur installation.
3. Shift the chain onto the big cog. If it does not shift quickly and smoothly, or if the chain is thrown into the spokes, you'll need to adjust the lower limit screw (usually marked "L.") Turning it clockwise will limit the travel, which is what you want to do if the chain goes into the spokes.
If the chain does not quite get to the big cog, turn the limit screw counterclockwise to allow it to move further.
4. Now shift the chain down to the small cog. Turn the high limit screw (marked "H") until the derailleur pulleys line up directly below the small cog. Like step 3, clockwise turns limit travel and counterclockwise turns allow more travel.
5. Run through the gears to see how smooth the shifting is. Ideally the chain will shift cleanly between each and every cog without excess noise or hesitation. If shifting is not ideal, try to fine-tune the adjustments on the limit screws.
6. If your derailleur has a third adjusting screw, usually near the top by the anchor bolt, that is the "B screw" which will set the derailleur's body angle.
This is most important when you're in the big cog. Check to make sure there is about 6mm of space between the cog and the top derailleur pulley.
If there is not enough space, tighten that screw. If there is a huge gap, loosen the screw.
7. Now you can use the barrel adjuster to fine-tune shifting.
If shifting to larger cogs is poor, turn the adjuster counterclockwise a half turn and see if that helps. If not, try another half turn. This should lead to improved, more precise shifting.
Make sure down shifts are still crisp. If not, you will have to turn the barrel adjuster clockwise a little at a time until shifting is crisp in both directions.
8. Run through all the gears again to make sure shifting is crisp and precise.
9. Finally, you may want to check chain length if this is a new bike or if you have replaced multiple drivetrain components.
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