The shimano dura ace r9170 c60 carbon tubular disc rear wheel features improved aerodynamic properties thanks to its 60 mm deep 24 mm wide carbon rim the deeper rim reduces air turbulence caused by air flow over the spokes so increasing the straight line speed of the c60 the wider rim profile allows for wider tyres to be run helping reduce air resistance by creating a more linear contour between tyre and rim the use of wider tyres also produce lower rolling resistance and change the an