What Makes the Shimano Dura-Ace 10-Speed 11-21t Cassette Special?

The Shimano Dura-Ace 10-speed 11-21t cassette is a race-specific close-ratio option for criteriums and flat road races where maintaining cadence through tight gear steps matters more than climbing range. The mixed-material construction pairs an aluminum cog carrier with four titanium and six steel cogs, delivering a cassette that is significantly lighter than an all-steel equivalent without sacrificing the wear resistance needed for competitive use. The 11-21t spread keeps gear jumps small enough that leg speed stays consistent through accelerations and sprint efforts.

Shimano's Hyperglide tooth profiling and shift ramp geometry enable fast, positive front and rear shifts even when applying power through a gear change, a requirement at race pace when slowing down to shift is not an option. This cassette is compatible with Shimano 10-speed road drivetrains including Dura-Ace 7900 and Ultegra 6700, and installs directly on any standard road HG freehub body with a standard lockring tool. For riders who race flat or rolling courses and want the tightest possible gear spread from a Dura-Ace cassette, the 11-21t is the right call.