Mavic's renowned Ksyrium line has been synonymous with lightweight aluminum training wheels since its birth in 1999, and after several recent additions, it's safe to say that the Ksyrium family is going through some changes. Ksyrium now counts a carbon wheelset among one of its own, now even being touted as the company's new flagship wheel. The featherweight Mavic Ksyrium Pro Carbon SL Disc Tubular Wheelset may look different than its predecessors, but these climbing hoops are still built with all of the reliability you'd expect from a wheelset bearing the Ksyrium name backed up with the added dependability of tubular tires and disc brake compatibility. Mavic uses 3K carbon fibers to shape the rims, and since they're tubular, it's able to leave out the heat dissipating aluminum bed included on the clincher versions, whittling the weight down further to a claimed 1,320g. The rims are shaped in a bullet nose profile, and while the wheelset isn't specifically called out as aero, Mavic constructed it specifically with climbing in mind, so the 25mm deep wheels are dependably stable while riding in crosswinds and tackling winding, long ascents. Mavic also paid close attention to the wheels' impact resistance, which earned high ratings, ensuring the wheels will be able to withstand long days on chip sealed roads and weather beaten shoulders while you're dreaming of buttery soft tarmac. Though it tends to privilege tradition, Mavic shows it's not afraid of well executed change by becoming the first manufacturer to introduce a mass produced wheel with a ratchet ring engagement system. The design, referred to as Instant Drive 360, is centered on a 40 tooth, dual ratchet construction that boasts nine degrees of engagement. This marks a significant step forward for factory built wheels because it features the kind of responsiveness and longevity normally reserved for third party hubs on hand built wheels. The Instant Drive 360 hubs also feature more reliable, no contact...