The VumaChrono uses a massive 30mm aluminum spindle and is by far the stiffest crankset ever tested by Zipp. Weight is kept to just 870g including the bottom bracket (175mm, 10 speed, 54/42). The VumaChrono has a unique, spider-less design with outer chainring held in place by 9 screws around the perimeter of the carbon face. The removable inner chainring has its own set of bolts (4 bolt, 110mm BCD), making the VumaChrono the first crank intended to accommodate both single and double chainring setups. The VumaChrono has an ultra-narrow 146mm Q-factor and 43.5mm chainline for Shimano, Campagnolo. Sram 9/10 speed functionality. Supplied with Zipp BB30 English threaded bottom bracket, grade 3 ceramic bearings, or you can use with a PF30 BB, press fit BB30 style.