How to Fix Gear Problems on a Bike

How to Fix Gear Problems on a Bike
Inevitably, time and wear take their toll upon bicycle gears. As shifter cables stretch with use, shifting becomes less precise, or "sloppy." The chain now moves reluctantly from one gear to another, or perhaps not all. Fortunately, you can fix the problem with little time and expense.

Instructions

Difficulty: Moderately Easy

Rear gears

Things You’ll Need:
  • 5mm Allen wrench
  • Needle-nose pliers
Step 1
Shift the chain to the smallest rear sprocket and the largest front chain ring. Using a 5mm Allen wrench, loosen the cable anchor bolt at the base of the rear derailleur. If your cable is more than a year old, replace it: Pull it from the bike, and insert a new one in its place.
Step 2
Standing behind the bike, check the alignment of the upper derailleur pulley with the sprocket above it. The two should be in line. If not, turn the high-range screw, marked with an "H" on the derailleur. Turning the screw clockwise will move the derailleur pulley toward the bike.
Step 3
Turn the barrel adjuster all the way in toward the derailleur body. The barrel adjuster sits on the back of the derailleur where the cable enters the derailleur body. Next, turn the barrel adjuster clockwise two full turns.
Step 4
Pull the end of the shifter cable taut with a pair of needle-nose pliers, and retighten the anchor bolt over it. If the cable is new, cut the end with wire cutters, leaving about 1 inch of cable at the end. Place an aluminum crimp on the end of the cable and pinch it into place with your pliers to keep the cable from fraying.
Step 5
Shift the chain onto the next sprocket. If the chain refuses to shift or hesitates, turn the barrel adjuster counterclockwise until the chain shifts crisply.
Step 6
Shift the chain onto the largest rear sprocket and smallest front chain ring. The upper derailleur pulley should be centered beneath the sprocket. Turn the low-range limit screw, marked with "L," to make any adjustment. Turning the screw clockwise moves the derailleur pulley away from the bike.

Front gears

Step 1
Shift to the largest rear sprocket and the smallest front chain ring. Loosen the cable anchor bolt on the front derailleur.
Step 2
Check the gap between the derailleur cage and the chain. Leave a gap between 1 and 2mm. To lessen the gap, turn the low-range limit screw on the front derailleur clockwise.
Step 3
Turn the cable adjuster barrel, located on the downtube of the bike frame, all the way in. Next, as with the rear derailleur, turn the adjuster barrel two full turns in the opposite direction.
Step 4
Pull the cable taut and retighten the anchor bolt over it. Shift the chain to the large chain ring and smallest rear sprocket. If the chain hesitates or refuses to shift, back out the barrel adjuster and try shifting again.
Step 5
Check the gap between the derailleur cage and the chain. Once again, aim for 1 to 2mm. To adjust, turn the high-range limit screw. Turning the screw clockwise will limit the gap.

Article Written By Matthew Ferguson

Matthew Ferguson is a writer living in Savannah, Ga. He has been writing for over 10 years and his work has appeared on various online publications. A collection of his short stories was published in spring 2010. He is a graduate of Appalachian State University.

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