Definition of derailleur in English:



  • A bicycle mechanism that moves the chain out and up, allowing it to shift to different cogs.

    • ‘It would be lighter, and it would seem that it would shift faster, by virtue of short-cage derailleurs.’
    • ‘If the chain is too long, the derailleur will rotate inward too far and bounce the upper jockey wheel through the chain on the largest cogs.’
    • ‘There's no barrel adjuster for the front derailleur, so eliminating derailleur rub in all gears is tough.’
    • ‘The spacing between nine-speed cogs is so close that the derailleur has to move very precisely under each cog or the chain will try to climb to the next one.’
    • ‘Move your mouse over a photo of a mountain bike to select an area, such as brakes or derailleurs, and click to simple repair procedures.’
    • ‘There is no way to have two cables operating the rear derailleur.’
    • ‘I can't seem to adjust the front derailleur to the point that I can eliminate chain rub in all gear combinations.’
    • ‘I had the problem with both front and rear derailleurs.’
    • ‘Just changing the crankset will work, but the shifting will not be as crisp as with derailleurs for a double, due to the long derailleur cages and extra chain not meant for those size cogs and chainrings.’
    • ‘And while the rear derailleur has been difficult to perfect, the front derailleur has proven to be the real challenge.’
    • ‘The first thing that I would check, is the position of the front derailleur in reference to the front chainrings.’
    • ‘The derailleurs are shifted by flicking the brake lever sideways.’
    • ‘The derailleur is the device that changes gears by moving the chain from one sprocket to another.’
    • ‘Then coat your bike's chain, derailleurs and pedals with a light lubricant.’
    • ‘The other side of the rollers will now contact the gears, and the derailleurs will now be laterally bending the chain the opposite direction.’
    • ‘No longer must we rely on our clumsy thumbs to arbitrarily slam derailleurs into the proper speed.’
    • ‘With just one lap remaining I was riding up one of the sticky mud climbs, when my derailleur jumped into my rear wheel, ending my race there and then.’
    • ‘My front derailleur and chain rings were so full of mud I couldn't change gears, so I was stuck pedalling in the big chain ring.’
    • ‘Unfortunately, the saddle, the derailleur and brake levers have black carbon.’
    • ‘As for adjusting for cable stretch, as the cable stretches, the derailleur will move to larger cogs faster and slower to smaller cogs.’


1930s: from French, from dérailler derail.