The racing zero has been redesigned for 2017 to better facilitate the use of 25c tyres making the rim slightly wider than before means 25c tyres can now be fitted with a more square profile for better rolling and aerodynamics the racing zero has the following features a carbon front hub with oversize flange is used creating a light weight but stiff hub the rear hub is single piece aluminium for increased stiffness 225mm external rim width differentiated rim heights 25mm at front for