The R stands for Rally

The 2021 models retain the same chassis and Charger RC damper as the 2020 models

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ETRTO (29) 622mm

E-Thirteen Helix 12 Speed Race Cluster - XD Driver - Intergalactic - 42-50T - 12 Speed Envelope Shipping The R stands for RallyUnlike SRAM Eagle, Helix R cassettes have replaceable gear clusters. That means ongoing service and replacement costs will be less than half that of SRAM cassettes. As an added bonus, Helix R 12s clusters are backward compatible with and can be used to upgrade your existing TRS+ 9 50 cassette. When installing the Helix R cassette, as with any cassette, it's recommended to check for chain wear. If your chain shows 0. 5% or more wear, you will