My front derailleur is stuck in high gear. No matter how I shift the gears the cable would not tighten hence the bike will not change from high to low gear. What is the cause of this? Btw it is a Shimano Tiagra.

  • So you're saying that changes to the left hand gear lever do not make the front derailleur move? Can you push the cage by hand and see any motion? Can you pull on any exposed inner cable and effect a movement in the cage? – Criggie Aug 9 '17 at 10:32
  • The possibilities are 1) broken shifter 2) broken or stuck inner cable 3) frozen derailleur, or 4) maladjustment of cable length or limit screws. Provide a bit more info and we can focus in on a good relevant answer. – Criggie Aug 9 '17 at 10:32
  • As far as I know all road front derailleurs are low-normal, which means the cable should loosen when shifting to small ring. Can you move the derailleur cage after you detach the cable? – ojs Aug 9 '17 at 11:23

Set the shifter to low.

With the shifter at low and the derailleur stuck at high, the cable should feel slack. If it still feels tight, the cable may be jammed or corroded, so replace the cable, or find whatever's crushing the outer cable (if the outer has been crushed you may need to replace it too).

On the body of your front derailleur you should find two limit screws, labelled "H" and "L". If the tip of the "L" screw is making contact, unscrew it (anti-clockwise) to allow the mech to move towards the low position. If the mech doesn't move and you get space at the tip of the screw, one of the mech's pivots is seized.

  • 1
    'Outer cable' is usually is referred to as the 'cable housing' – Argenti Apparatus Aug 9 '17 at 17:32
  • Manufacturers call it that. Most cyclists use "inner cable" and "outer cable". – Emyr Aug 9 '17 at 17:35

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