Cyclocross bike type mens geometry sloping comfort frame sizes l s m bike frame sizes cm 48 49 51 54 57 59 cm colours white black model 2017 series kona rove frame material aluminium frame characteristics butted frame alloy 6061 aluminium fork kona fork material aluminium gear system with derailleur number of gears 16 rear derailleur shimano claris derailleur model shimano 2400 front derailleur shimano claris gear shift brake lev