re: 60 MPH...achieveable? Who cares?!? Let blueprint an engine!
60 mph...that's fast. Here is a totally unrelated anecdote:
I often ride my 66cc Schwinn to school (I take my NAU classes at Scottsdale Community College) and the 11 mile ride is a coin flip between street riding (motor engaged) or pedaling the beautiful bike path that winds through Scottsdale and dumps me a few miles away from campus. In any case, I have to take Pima (Arizona residents may know the road) southbound to Chaparral. On this flat stretch there is a bike path that goes with traffic, and, for about a mile or so between between McDonald and Chaparral the bike path merges behind a wall and onto a destitute neighborhood straight-away. What I like to do, is stare down the driver of the nearest car at the intersection on Pima and McDonald (usually a suspicious maladjusted stare, only it is totally innocent...but they don't know that, however) - only so that they will remember me in the next 5 minutes. I pedal through the intersection and engage the motor and haul ass down this mile stretch of neighborhood road, often times beating the car I stared down to the intersection at Chaparral and Pima, where I cross the street (motor disengaged) and continue my maladjusted stare. It totally freaks people out. I have seen many-a-person give me that how-the-****-did-you-get-here-so-fast look. Its incredible how often people don't realize you have a motor on your bike until you turn it on.
So yeah, now that you know that, a 60 mph bike would really up my game.