Rear

Shimano Ultegra Di2 Shadow rear derailleur. - Sleek integrated appearance - New low-profile design - Shimano Shadow RD - Race endurance - Optimized slant angle - Maintain race concentration with more intuitive shift control - System communication with front derailleur - Shimano Synchronized Shift - Wide compatibility - Short cage covers: 11-25T to 11-30T - Medium cage covers: 11-28T to 11-34T - Average Weight: 242 grams (SS type), 249 grams (GS type)

Riders want the derailleur to do its job shifting on command, whether under climbing load or the stage finish. The GX Eagle derailleur gets it done with an updated cage architecture that improves chain management. Refined to work with the new 10-52T cassettes, it's also backward-compatible with 10-50T cassettes for greater versatility and incremental upgrade. It's finished with the new GX Eagle master colorway to complement any cassette and chain colorway a rider wants from the Eagle Colorsystem. - Backward-compatible—works with both 10-50T and newer 10-52T cassettes - Updated cage architecture provides better chain retention and precise shifts

The heart of this microSHIFT Acolyte derailleur is the innovative SpringLock system. By pairing a customized linear rate high tension spring and a dual stage activation mechanism, we’ve developed a system that can provide substantial chain security when you need it and can be turned off when you don’t.  To engage the clutch, turn the engagement bolt clockwise until it clicks. There’s no way to overtighten the bolt. To disengage the clutch for wheel removal, flip the switch. It’s that simple. - Innovative SpringLock chain retention keeps chain in place over rough terrain - Direct path cable routing for smooth and responsive shifting - Compatible with 12-42T and 12-46T 8-speed cassettes - Compatible with Acolyte shifters only

XLE Rear Derailleur for 10-speed Shimano drivetrains - For MEGA Sprockets w/large cog size 36-42T - Compatible with single, double, or triple cranksets - Total Capacity: 47T

Shimano's Tiagra Rear Derailleur GS (10-speed) is sleek, balanced and consistent. The Tiagra 4700 series provides serious entry-level riding performance with trickle-down technology from the top shelf Dura Ace line. - Model Number: RD-4700-GS - Series: Tiagra - Cassette Compatibility: 10 - Maximum Sprocket: low sprocket: 34T / top sprocket: 12T (front double) / 20T low sprocket: 32T / top sprocket: 12T (front triple) - Minimum Sprocket: low sprocket: 28T / top sprocket: 11T (front double) / 20T low sprocket: 25T / top sprocket: 11T (front triple) - Maximum Front Difference: 16T (front double) / 20T (front triple) - Total Capacity: 39T (front double) / 41T (front triple)

The Box Two Prime 9 Rear Derailleur is very similar to the Box One version however, to be more wallet friendly, it offers a non adjustable Tri-Pack Clutch, bushing pulleys and some muted finishes. Box Two rear derailleurs are still optimized for 11-50t cassettes and offer durability and performance for the most demanding terrain, just at lower price!