The rear tires on this bike should be used front and rear. Create an adult version utilizing a 50cc motor..a lite weight version of the Harley Hummer or aka: dkw 125... You will then have a bonafide tangible timeless machine in which parts would be available..serious transportation as well as an economic commodity,..providing a product and an industry as well as fulfilling the transportation needs and recreational wants of many...What I can\'t understand is why is taking everyone so long to figure this out ... The Harley Hummer / aka: german DKW was already here, now ,everyone is putting a motor on a bicycle and will eventually discover or accidentally re-create the dkw.! 50cc motor keeps a legal moped status . How about it people..? wake up and build this bike !