How to Adjust a Derailleur

Geared bicycles are very famous. They have these Derailleur gears. Derailleur consists of a chain, multiple sprockets, mechanisms that move the chain between the sprockets. These are referred to as gears but they are different from bike gears. There are usually two derailleur in a geared bicycle. Each derailleur is responsible for shifting the drive chain between the gears. The derailleur need to be adjusted periodically, so that it functions smoothly. You do not need to take your bicycle to a repair shop or some expert to adjust the derailleur of your bicycle. You can do it yourself reading the instructions given below, that will help you know how to adjust a bicycle derailleur.

Derailleur adjustment includes adjusting the cable tension and range settings. Range settings are necessary as it controls the deflection of the derailleur. It prevents the derailleur going to the extreme left or extreme right. The cable tension controls the movement of the derailleur in this range. All this sounds difficult, but it is practically easy. Follow the instructions given below to adjust a derailleur.

How to adjust a derailleur?

Equipments needed to adjust a derailleur:

  • Allen Wrench
  • Needle Nose Pliers
  • Philips head screwdriver

Adjusting the Rear derailleur:

  • Firstly, shift the chain to the largest ring in the front chain and to the smallest ring rear cog on it.
  • The anchor bolt on the cable of the rear derailleur can be loosened using a 5mm Allen wrench.
  • Once you have loosened it, check the alignment of the smallest rear cog, and the upper derailleur. Both these should be aligned in one line. If it is not aligned in one line, using a Philips head screwdriver, adjust the screw located at the hind side of the derailleur. It is marked with alphabet ‘H’. Rotate the screw in clockwise direction. This will align them in one direction and move it towards the bicycle.
  • There is also a barrel adjuster on the hind side of the derailleur. Turn it into the derailleur and then turn it out in the opposite direction.
  • Now pull the cable using pliers, and tighten the bolt situated over the cable once you have pulled the cable to the extent.
  • Next step is shifting the chain on the largest rear cog. If it is impossible to shift the chain, then adjust the ‘L’ screw on the hind side of eth derailleur. The screw is marked with alphabet ‘L’. Turn the screw till the upper pulley of the derailleur comes below the cog. Now turn the screw in clockwise direction.

Adjusting the Front Derailleur:

  • Again, start with shifting the chain towards the smallest ring at the front of the chain, and the largest rear cog. Using the Allen wrench, open the anchor bolt on the front cable of the derailleur.
  • Once you have loosened it, check the gap between the chain and the derailleur. The gap should be exactly 1 mm. If it exceeds or is less than 1 mm then adjust it by turning the ‘L’ screw. Turn it to get exactly 1 mm gap between the two.
  • Next step is adjusting the barrel adjuster on the derailleur cable. First turn it in towards the bicycle, and then two turn outside.
  • Using a pair of pliers, pull the cable to adjust it correctly. Pull it to the extent, and then tighten the anchor bolt over it.
  • Again, shift the chain to the cog and the ring, and if it does not move, rotate the barrel adjuster in anti-clockwise direction to let the chain move freely.
  • Again, check the for 1 mm gap between chain and the derailleur. Turning the ‘H’ screw, you can adjust this gap.

In this way, you can adjust the derailleur of the bicycle. You need to adjust it differently for front and rear adjustments of the derailleur. Using a screwdriver, and a pair of pliers, you can yourself adjust the derailleur next time, if it poses any problem.


Related Content:

  1. How to Adjust Bike Gears
  2. How to Adjust Cantilever Brakes
  3. How to Adjust Motorcycle Chain
  4. How to Adjust BMX Brakes
  5. How to Adjust Caliper Brakes
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