e*thirteen turned the Bike World on it's head with our extensive widest available range cassettes for MTB and Gravel. The newest generation of e*thirteen cassettes deliver that range with unmatched cross-compatibility for flawless shifting performance with SRAM™ and Shimano™ drivetrains. e*thirteen Helix cassettes offer industry leading weights, and the highest gear ranges available thanks to an exclusive 9T highest gear cog. Our 9T cog also lets you step down one chainring size with the same top end gearing for better ground clearance and an overall lighter drivetrain. e*thirteen Cassettes are also serviceable with a 2 part design that allows alloy granny gears to be replaced as needed independent of the steel cogs. Finally, we added a wide range of anodized color options and a higher wear life Intergalactic PVD color option too. Reduce weight, increase range, personalize and experience the freedom of choice with Helix R and Plus cassettes.