How to Replace Sprockets on a Trek

Trek bicycles with multiple gears use a device called a "cassette," which is a cluster of sprockets affixed to the side of the rear wheel. Working in concert with the chain and front chain rings, sprockets allow the cyclist to choose from different gear ratios. Chain friction causes sprockets to wear over time, sometimes resulting in "chain skip." Chain skip occurs when the teeth surrounding the sprocket no longer engage the chain. The problem is resolved by replacing the sprockets in question.

Things You'll Need

  • Cassette remover
  • Adjustable wrench
  • Chain whip
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Instructions

  1. Trek Wheel Removal

    • 1

      Open the rear wheel quick release. The quick release is a skewer in the center, or axle, of the wheel that allows for quick removal of the wheel. The release has a lever at one end that opens and closes.

    • 2

      Remove the nut at the end of the quick release opposite the lever. Remove the nut by hand.

    • 3

      Slide the quick release from the wheel.

    • 4

      Raise the rear of the bicycle and push the rear wheel down, dislodging it from the Trek bicycle frame. Grab the wheel and remove it from the bicycle.

    Trek Sprocket Removal

    • 5

      Stand the wheel upright on the ground. Turn the wheel so that the sprockets face away from you.

    • 6

      Insert the ribbed end of the cassette remover into the center of the sprocket cluster on the side of the wheel.

    • 7

      Lock the head of an adjustable wrench around the body of the cassette remover to hold the remover in place.

    • 8

      Attach a chain whip to one of the Trek bicycle sprockets. The chain whip consists of a handle and chain. The chain portion holds the sprocket cluster in place, preventing it from rotating during removal.

    • 9

      Turn the adjustable wrench, and cassette remover, counterclockwise against the chain whip, in turn loosening the locking ring that holds the sprocket cluster in place.

    • 10

      Loosen the locking ring the remainder of the way by hand, and remove it. Remove any or all sprockets from the side of the Trek bicycle wheel. Sprockets slide on and off.

    Trek Sprocket Installation

    • 11

      Install the new sprocket(s) on the side of the Trek bicycle wheel. Larger sprockets slide on first.

    • 12

      Screw the locking ring into the center of the cluster of sprockets, and tighten the ring by hand as much as possible.

    • 13

      Insert the cassette remover into the center of the sprocket cluster. Tighten the locking ring fully, using the adjustable wrench.

    • 14

      Reinstall the wheel on the Trek bicycle. Slide the quick release through the side of the axle opposite the sprockets.

    • 15

      Thread the quick release nut back onto the end of the quick release. Close the quick release lever.