Shifting Adjustment

Many bikes new and old may have shifting trouble or noisy gear combinations. This is a short tutorial to make the gears work like they should.

 - The rear derailleur’s limit screws must be adjusted properly. These screws will stop the derailleur from moving too far past the gear cluster. They're usually located either on the front of the derailleur or on the left side. The low limit stop (usually marked L) is the most critical. This screw should allow the chain to engage the biggest rear cog, but NOT shift past it into the spokes. The rear derailleur’s upper pulley should be centered directly underneath the biggest gear when it hits the L limit screw. Similarly, the high limit screw (H) should not restrict the chain from moving to the smallest rear cog, but shouldn't let the chain move past it.

 - The front derailleur should not rub the chain. The barrel adjuster on the shifter controls the derailleur’s position for the middle gear (if your bike has straight handlebars). The front derailleur's position in the small gear is controlled by the low limit screw (L), and the high gear position is controlled by the high (H) limit screw. Improper limit screw adjustment can throw the chain off the sprockets, so be careful.

 - Indexing adjustment: Generally, the rear derailleur’s upper pulley should be positioned right below the selected gear. Use the barrel adjuster to adjust hesitant shifting in ¼ turn increments. Screwing it inwards (clockwise) makes it easier to upshift, unscrewing it (counterclockwise) makes it easier to downshift. These adjustments are sensitive so test the shifting after each quarter turn.

If the derailleurs are properly set up but the shifting is still hesitant, a sticky cable is usually to blame. Slide out the cable housings, clean the inner wire, then oil it before sliding the housings back in place. On newer bikes you can usually slacken the cable, then unhook the housings from the metal cable stops on the frame to clean the inner wire. On older bikes with closed cable stops you have to disconnect the shift cable. Frayed or kinked cables will also cause shifting problems. Comment with any specific questions, since every bike's situation is unique.