This bike is designed for adults with heights 170-180cm. For comfortable ride bike is equipped with 28" tires that are optimized to let you rip across a wide range of conditions. Bike has 21 speeds to choose from and MTB pedals to provide more secure and efficient ride. Fork: Steel Front derailleur: Dacron TX 30 Rear derailleur: Dacron TZ 35 Stem & handlebar: Steel Chain wheel: Steel 42 T Freewheel: SunRun Chain: DT 050 Fronthub: Steel 36 Rearhub: Steel 36 Rim: Double wall alloy Seat tube: Steel Tyre: City tyre Accessories (not included): Chain housing, Front & Rear carrier, Front & Back lighting, Lock // Assembly: Bicycle comes in the original factory package, 85% assembled (front wheel, handlebars, seat, pedals might be removed and need installing). Tools for assembling the bicycle are not included in the package. Client is responsible for correct bicycle assembly, preparation for use and initial maintenance of the bicycle at any service centre (service record in the maintenance sheet/warranty card is mandatory). In case of violating this rule warranty will not be effective. Regarding the assembly of the bicycle we recommend to consult a qualified technician.