hi Pcarlson,
wow you can get 73km/h from cyclone motors? my max speed i got is 70km/h from the 1000watts/ 1500watts big motor. now my controller 48v 1200watts from cyclone had somehow not working. i have make a full switching to HUb Conhis motor for 1000watts, 48v. On flat i can get a good speed too 52.2km/h . Myself is weight 65kg, was one possible making abit faster. my vpower 48v 20hr. (actual power is 48v 15hr)/ 710watts total, i can get a good range 95km, at a slow speed of 30km/h ~ slow. it depends how fast i need to run. if im running 40km/h ~ 52km/h - i will be using 12 ~14 watts/km.
cammy_CC 500watts kit, 48v . is also exactly the speed top speed like yours 41km/h. is taking 15.44watts/km. takes a bit more power compare to 1000watts kit. nowdays when i done 50km range plus, i will go for a charge. so that the battery lifespan will be longer.
kentlim