I live in the country many 50 mph roads I run 17-18x40 gears, tuned clutch dmp 70cc not ported inside but intake and exhaust opened, modded hi comp head, techno circuit pipe. I go almost 50 mph with a 14mm bing with fast take off and 52mph with 15mm bing. I got 2 steep hills 10%+grade I go up at 25-30mph no problem. For me stock gearing cost waaay more to use cause you got to rebuild your engine with a needle bearing crank not just kit and go way worse gas milage too. I ran against stock geared 70 cc needle bearing 19 mm phbg bikes that cost 400.00 more to build and beat them with a 30+ year old unopened e50 bottom ( my tuned clutches really help though) I don't have a video camera but I hope to have one soon to show that medium geared bikes rip too