Urban bike wheel size 28 inch model 2015 frame material aluminium frame alloy 6061 aluminium bike frame sizes cm 60 56 53 58 cm frame sizes l xl colour grey brake type u brakes brakes tektro r315 gear system internally geared hub igh rear derailleur sram automatix number of gears 2 braking system rim brakes rear chain wheel teeth 17 front chain wheel teeth 46 chain kmc z510 rims shining tyres kenda kwick roller sport stem hl d404