The Shimano XT RD-M8130 11-Speed Rear Derailleur is built for E-bikes, touring, and commuters who seek mountain bike-level gears without decreasing durability. Shadow+ tech ensures your chain stays tensioned properly, while its low-profile design keeps the derailleur safe and protected. The XT...

On top of delivering smooth, effortless shifting in all conditions, Shimano's XTR Di2 RD-M9050 Rear Derailleur will make the aft-end of your drivetrain smarter than it's ever been before. With Shimano's Synchronized Shift technology, the front and rear derailleurs operate in sync and have the...

When we're outfitting our dream race bike, we opt for the best when it comes to mechanical shifting. Shimano's M9000 XTR Rear Derailleur is the top-of-the-line offering for Shimano's 11-speed mountain bike drivetrains. It's capable of handling cogs up to 46 teeth, and can be set up in 1 x 11, 2 x...

With the release of the XTR M9100 12-speed drivetrain, Shimano jumps right back to the front of the pack by expanding the available gear range and offering better shifting performance than ever before. The new XTR RD-M9100 Rear Derailleur is specifically optimized for Shimano's new wide range...

Shimano may have taken its sweet time when jumping into the world of 12-speed, but patience is a virtue, and it seems like our wait was certainly rewarded, as its new XTR 12-speed groupset soars right back to the front of the cutting edge, while offering even better shifting performance than...

Chain slap is something we all have to live with, but Shimano's ZEE RD-M640 Shadow Plus makes it a whole lot less cringe-inducing by including its now-famous clutch technology. By increasing spring tension when it's engaged, the clutch reduces slap and the risk of dropping a chain, making it a...

The SRAM GX Eagle 12-Speed Rear Derailleur harmoniously shifts through all 12 gears of your Eagle drivetrain without noisy chain slap or annoying ghost shifts holding you back on the trail. Borrowing shifting technologies from its pricier XO1 sibling, the GX Eagle 12-Speed Rear Derailleur is a...

Built with tested perfection, the SRAM GX Eagle AXS Rear Derailleur is the latest and greatest in trickle-down technology. Cross-compatible with all other AXS products on the market, this innovative wireless tech introduces a more manageable price point. We're beyond excited to install the new...

SRAM's new electronic transmission derailleur is now in a value-packed GX eagle version. The SRAM GX Eagle AXS Transmission Rear Derailleur packs all the same performance features as the XO and XX transmission derailleurs but with a slightly more value-based build and a slightly heavier weight....

Masters of trickle-down technology, SRAM has impressed us again with the GX Eagle AXS Upgrade Kit. We're installing this on our bikes right away, ditching the cables and housing that clunk around in our frames all day. Long-awaited, GX AXS Eagle opens the door for a lot more than just dentists to...