Cassette weight drops fastest when you remove material from the largest cogs—the ones with the most metal to begin with. SRAM's XG-1270 E1 cassette applies this logic across the entire 12-speed range, machining the upper cogs from a single block of steel rather than stamping and riveting individual rings. The result is a cassette that runs 80 to 100 grams lighter than SRAM's standard Rival cassette depending on ratio, without changing shift quality or durability expectations.

The E1 designation indicates compatibility with SRAM's extended XDR driver body, which adds roughly 1.85mm of width compared to the standard XDR freehub. That extra space allows the cassette to nestle closer to the spokes, giving frame designers more room for tire clearance or shorter chainstays. If you're running an E1-compatible wheelset and want to shed rotating weight where it matters most—at the outer edge of your drivetrain—this is where the grams come off.

Three gear ranges cover the spread from flat-road racing to mountain stages. The 10-28T keeps jumps tight for criteriums and rolling terrain where you're rarely cross-chaining. The 10-33T opens up the bottom end for longer climbs without sacrificing top-end speed. And the 10-36T gives you bailout gearing for steep grades, trading some gear-step consistency for range that keeps you spinning when the road tilts up.... Read More