One of the most exciting developments within the Dura-Ace 9100 drivetrain system is the push towards greater cassette range. As riders, drivetrains, and riding styles have changed, so have the conceptions about what is the appropriate cassette combination. We are seeing massive variation within the pro peleton, never mind domestic racing and all levels of enthusiast riding experience. As Shimano has stayed with 11-speed and a focus on double chainring cranksets, Dura-Ace has limited large cog size to 28T. Now, with changes to the 9100 short cage rear derailleur, the CS-R9100 11-speed cassette gains an 11-30 cassette. As with the previous generation, the cassette features the five largest cogs in titanium, with the remainder in steel. An 11-30 cassette weighs just 211 grams.

Shimano hasn't changed the physical set-up of the cassette with carbon fiber spiders carrying the largest cogs, the two largest paired, then the next three. The next three of the sculpted, nickle-plated steel cogs are solo with three separate 11-speed spacers, then the final three have integrated spacers . An anodized alloy lock ring finishes out the run. The only substantive changes would be very difficult to identify, as the engineers have continued their goal of creating the most efficient, low friction drivetrain with new tooth profiles on the cogs to better manage the wider range and extreme chainlines.

Of course a full range of cassette options is being offered, and many cyclists will opt for multiple set-ups depending on course, route, event type, etc. If you weight and performance conscious, keep in mind that as of 9100's release, there is no 11-30 Ultegra option, and the 11-28 comes in 40 grams heavier, while the 11-32 is 81 grams heavier. It is true the titanium cogs can wear faster, but for race wheels, the Gran Fondo goal of the year, or just the lightest weight and highest performance available for Shimano 11-speed drivetrains, only the Dura-Ace CS-9100 cassette will do.