Your NEO 2T ships with a Shimano/SRAM 9-11 speed freehub body installed, which covers most riders. If you're running Campagnolo or SRAM's 12-speed XDR cassettes, this replacement freehub body lets you use your actual outdoor drivetrain indoors. The aluminum body swaps in with a 5mm hex key, and matching your outdoor cassette to your trainer setup keeps shifting performance consistent between road rides and indoor sessions. Running the same cassette you ride outdoors also means you're training on the exact gear ratios you'll use on the road.

The Type 2 freehub body works on NEO 2T trainers as well as Flux 2 and Flux S models produced after Q4 2019. If you bought your trainer secondhand or inherited one with the wrong freehub standard, this swap gets you running your own cassette rather than buying a different one just for the trainer. Campagnolo riders need the dedicated Campy body for 9-12 speed compatibility, while SRAM riders running 11 or 12-speed XDR cassettes need the XDR-specific version. The cassette spline patterns differ between standards, so you can't just force a Campagnolo cassette onto a Shimano freehub.

Installing a freehub body takes about ten minutes once you understand the axle system. You remove the trainer's right side cap, slide off the old freehub, install the new one, and reinstall the cap. Some riders keep multiple freehub bodies if they switch between bikes with different drivetrain standards, though most just match the trainer to their primary indoor bike and leave it installed year-round. The tool-free cassette installation works the same as swapping cassettes on a rear wheel.