SRAM S500 Eagle AXS Upgrade Kit

The SRAM S500 Eagle AXS Upgrade Kit is the fastest path from a mechanical Eagle drivetrain to wireless shifting, without buying an entirely new groupset. If the crank, chainring, cassette, and chain on your bike are already Eagle 12-speed, this kit swaps in AXS electronics and leaves the rest of the drivetrain untouched — a meaningfully cheaper upgrade than starting over with a complete AXS groupset.

At the center of the kit is the Eagle S500 AXS rear derailleur, built around the same wireless architecture SRAM uses across its higher-tier Eagle AXS derailleurs. It's compatible with both 10-50t and 10-52t Eagle cassettes, runs a Type 3 cage damper to keep the chain quiet and controlled on rough descents, and seals against water and dust for creek crossings and muddy rides. The Overload Clutch is the feature worth knowing about before a rock strike happens: on impact, the motor gearbox disengages so the derailleur can move freely instead of bending, then resets itself back into position once the hit is over.

The kit pairs that derailleur with an AXS POD Controller, which replaces a mechanical shift lever with a wireless button that can be mounted and angled to suit the rider rather than the cable routing. Everything needed to get running is included — an AXS battery, USB-C charger, Eagle PowerLock, and a chain gap tool for setup — so there's no separate parts list to track down. For a rider who already has an Eagle drivetrain dialed in and just wants to drop the cable and shift wirelessly, this is the direct way to get there.