Re: fixie build new got to try it
Boygoesfast has sold those freewheels for motor sprocket for years- but if you do that, you have to have a pull start- the pull start adds an inch or more and then you need wider cranks to clear the pull start assembly. You'll also lose then the pedal start, that I use aLL THE TIME out on the road, because I'm forever coasting down from speed with the motor killled.
Anyway- fixie flip flop wheels ARE good motor wheels, because the motor sprock generally fits on right over the diameter of the hub once the fixed sprocket is removed- they can be then mounted with a rag joint and the spacing is usually good-
I've been using flip/flop hubs with LARGE FLANGE Smooth sided hubs, because then you can drill the sides of the hubs and bolt a motor sprok directly to the hub- an alloy hub, titanium bolts and an alloy motor sprocket make perhaps the lightest assembly possible-
throw on a 415 Trike chain at half the weight, and no tensioner, and you've eliminated a GREAT BIG BUNCH of original kit weight
the thruster frame may be hard to lose the tensioner though, because it probably will have chain stay frame clearance issues without one. I'd still like to build a classic diamond road frame with that set-up and a small plastic tank to lose all the tank and cap weight- but I'd definitely use a 50 cc and not 66. The tank will be in the way of much normal peddling on a Thruster too.
My lightest bike now -700C wheels with 32mm tires on a modern lighter Huffy cruiser frame with all alloy acruments- bars, stem cranks- weighs in at about 47 pounds unloaded.
I'd like to build a light bike and think I could get it down to just over 40 lbs, using the lightest stuff and a 50 cc motor- but probably NOT going to happen even when I have an old Atala frame and everything else. Too old- tired of mechanical work, and it agitates my arthritis, and gotta play my musical instruments while I still can!