How to Repair a Shimano STX RC
- 1). Spin the cranks of the bicycle forward and shift into the smallest cog in both the front and rear of the drivetrain, using the shifters on the handlebars.
- 2). Loosen the rear derailleur cable stop bolt, under which the rear shift cable runs, using a 5mm hex wrench to free the rear shift cable. Do the same to the front derailleur cable stop bolt to free the front shift cable.
- 3). Spin the cranks of the bike a few times to settle the two derailleurs. Inspect the alignment of the rear derailleur pulleys and the small rear cog. If the chain is pulled to the right by the pulleys, tighten the high-limit screw, using a Phillips head screwdriver, until the chain, pulley and cog form a straight line. If the pulley pulls the chain to the left, loosen the high-limit screw until everything is aligned.
- 4). Pull the rear shift cable taut beneath the cable stop bolt, using a pair of needle-nose pliers, then tighten the cable stop bolt with a 5mm hex wrench to secure it in place.
- 5). Inspect the alignment of the chain with the front derailleur cage from above the bike. If the chain rubs on the outside of the derailleur cage -- you may need to spin the cranks to make certain, tighten the low-limit screw, using a Phillips head screwdriver until the chain is centered in the cage. If the chain rubs on the inside of the derailleur cage, loosen the low-limit screw until the chain is centered in the cage.
- 6). Pull the front shift cable taut beneath the front derailleur cable stop bolt, using a pair of needle-nose pliers. Tighten the cable stop bolt, using a 5mm hex wrench to secure the cable in place.
- 7). Take your bike for a test ride and shift through all of the available gears. Since you have effectively reset the gear-switching system to the way it was when the bike left the factory, shifting should be accurate and consistent.
