It took years to develop the Zipp VumaChrono and by the time Zipp was done, even theirr engineers were stunned by the results: 9 seconds faster over 40km compared to the next fastest TT crankset. That's about the same as taking 12 spokes out of your front wheel (which they do not recommend). But VumaChrono breaks new ground with more than its radical shape.
It has a unique, spider-less design and an outer chainring that's only a few millimeters taller than the teeth themselves and is held in place by 9 screws around the perimeter of the carbon face. Meanwhile, the inner chainring sits flush against the interior face of the carbon, all the way to the bottom bracket cups. It has its own set of bolts, making the VumaChrono the first crank designed to accommodate both single and double chainring setups. At just 860g, it also happens to be the stiffest crankset Zipp has ever tested for chainring deflection - by a factor of 10.
Because time trialists and triathletes require such a high degree of personalization from their equipment, the VumaChrono is available in 6 lengths from 167.5mm to 180mm and three chainring combinations: 53/39, 54/42, or 55/42. It also features an ultra-narrow Q-factor of 146mm.
The Chrono features an ultra-stiff, 30mm spindle and ultra-smooth American-made bearings with a ceramic bearing upgrade available as well. The Chrono is compatible with 68mm bottom bracket shells with English or 70mm Italian threading, and is designed for Zipp external bottom bracket cups.