This rim features legendary Firecrest technology, providing outstanding aerodynamic performance, straight-line power transfer efficiency, great stability in crosswinds and is perfect for climbing due to its weight. They deliver precise handling and stability on adrenaline fuelled descents and snappy acceleration when putting the power down. Firecrest Design Benefits The fundamental benefits of the Firecrest design are that its shape moves the centre of air pressure backwards, giving the 82mm deep rim the crosswind stability of a much shallower rim. Also, the 26mm wide brake track (at centre) enables the Tubular tyre to achieve a wider, more stable profile without compromising rolling resistance. Exceptional Rolling Efficiency At the centre of this wheel is the Zipp 177 hub, which features unmatched durability and advanced bearing protection, with no bearing pre-load required. This hub provides exceptional rolling efficiency and a consistent performance output that you will be hardpressed to find a rival in the same wheel class.