Garage Files: How To Keep Your Derailleur & Cables Finely Tuned

 

 

settled in and seated properly. Reset, go back to neutral, re-tension the cable, and now securely tighten the cable anchor bolt.

Step 8: Trim the cable a few fingers in length from the anchor point and crimp on a cable end cap.

Getting to Know Your Shifts

When you look closely at any derailleur, you will see that it is fitted with limit screws. Some brands’ bolt heads use an Allen key, while others can be turned with a Phillips screwdriver. These stop the derailleur from moving too far inward or too far outward. When you look even further, you can see the limit screws stopping the derailleur at each end of its range of movement. The main purpose of these limit screws is to prevent the chain from going into the spokes or into the frame. In some cases, they are labeled on the derailleur; in other cases, they are not. Regardless, the name and function can be found on any derailleur system.

Tightening/loosening the H-limit (high-limit) screw restricts the chain from going off the lowest cog. The L-limit (low-limit) does the opposite by stopping the derailleur from moving the chain beyond the largest cog and into the spokes. Another bolt adjustment found on the rear derailleur is the B-adjust or B-tension screw. This is used to adjust the guide pulley away from the cassette and allow for a gap so the chain can run through the system appropriately.

Step 1: With the H-limit, the goal is to dial it in and align the center of the guide pulley (top wheel) on the derailleur with the outboard edge of the smallest cog. We use a thin Allen wrench to help us align this correctly while turning the H-limit screw for proper alignment.

Step 2: Now we get shifting! Check the cabling one last time to make sure there is no slack. With the chain in the smallest chainring and smallest cog, hit the shifter one click while pedaling the bike.

—If the chain does not move into the second position cog, use the barrel adjuster and add some cable tension until it jumps into the next cog.

—If the chain over-shifts into the third cog, decrease the tension with the barrel adjuster until the guide pulley is in line with the second cog.

Step 3: Shift through all remaining gears. If the derailleur hesitates its shifting…

 

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