The frame is a 1970's Sears Free Spirit I found in the roadside trash on junk day. The wheels are 26" 1 3/8 rims which have a nice low rolling resistance for easy pedaling. The SBP shift kit lowers the drive chain resistance which also makes for added ease. pedaling with the motor turned off. The shift kit is the best add on, I can now climb most any hill without pedaling and cruise at 25 mph with very little vibration. I say never pass up an old bike discarded to the curb as trash.