Ask a Mechanic | Understanding Rear Derailleur Cage Length Ask a Mechanic | Understanding Rear Derailleur Cage Length Greg O'Keeffe2016-10-06T11:16:03-08:00 Jenny wants to know, “What is the difference between short, medium, and long cage Ask a Mechanic | Understanding Rear Derailleur Cage LengthGreg O'Keeffe2016-10-06T11:16:03-08:00