Atb bike type men wheel size 26 inch model 2016 series bergamont vitox frame material aluminium frame alloy 6061 aluminium frame geometry diamond bike frame sizes cm 38 42 47 51 56 cm frame sizes m xs colour grey braking system rim brakes brakes tektro y855 bicycle fork suspension fork fork suntour m3030 wheel travel 75 mm rear derailleur shimano acera number of gears 21 gear system with derailleur front derailleur shimano fd tx50