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Summary: Learn how to change a mountain bike derailleur and what to do with your old one in this free bike care and maintenance video series.
Views: 4,385 | Tags: repair, maintenance, mountain, bike, ride, parts, bmx, bicycle, outdoors, bicycles, street, mountainbikes
About the Expert
Mickey Denoncourt Mickey Denoncourt received a degree in applied physiology from Hampshire College in Amherst, Massachusetts. Mickey is a Category 3 road racer, Semi-professio... read more
As you find yourself changing the number of chain rings that you use from three to two, or from three to one, or two to one, you'll find that you may be able to also get away with changing the length of your derailleur cage. Most bikes come with a long cage, which is designed to take up a greater difference in front chain rings. The smaller the difference that you have, the shorter length you can get away with. So, this is a long derailleur cage. This derailleur here is medium length. You can see that it's a little bit shorter. And then, this cage here, is a short cage, which is once again shorter yet. So, medium cage derailleurs are good if you're not running an extremely large gear range in the rear as well, and you're running three cages, so that would be the medium cage one. The long cage is good if you're running three rings up front, and a wide range cassette in the back, like an eleven or twelve-thirty-four. The small, short cage derailleur, which originally, these were only on road bikes and now a few companies make them for mountain bikes specific use, is really good for a double-ring application with a tight rear cassette, or a single-ring application because the shorter the cage, the shorter you can make your chain and the less swing weight there is, so the snappier and more effective the shifts are. Another reason to change your rear derailleur is obviously, if like this one, things are broken. So, when we're changing out our rear derailleurs we want to make sure that we set out limit screws correctly, and that we're setting cable tension the right way. You can follow some of those steps other places, but basically you want to make sure that you're aware if you have a Shimano style derailleur with a rear loop and a different cable pull, because one type of shifter works with one type of derailleur. So, yeah, don't be afraid to change out you're derailleurs to save some weight and increase some performance, or just to suit your needs better.