KCNC's mixed material cassette offers a way to shave grams off your ride. Titanium and scandium alloy sprockets make up most of the 12-25T setup we tested (also available in 11-23 and 12-27), but the largest four sprockets are machined from superlight 7075 aluminium alloy.
At 131g the KCNC is much lighter than comparable top-end cassettes. Unfortunately, shifting is noticeably slower than the Shimano Dura-Ace unit it replaced because there's signiﬁcantly less proﬁling of the teeth to help the chain move between sprockets.
Our previously stealthy drivetrain also acquired a constant rattle, no matter how we adjusted the derailleurs. Durability is also seriously reduced compared with steel cassettes, with shift performance steadily dropping as the softer scandium sprockets wore.
After 1,000km of hard Alpine riding our test unit was worn out, though in more moderate usage we’d expect to achieve the 1,500km lifespan KCNC claim. The compromises made to achieve the superlight weight mean we’d only recommend the KCNC for die-hard gram counters who ride mountainous sportives.