Originally Posted by biknut
Just be advised, no matter how you do it, dependable 40mph riding with cost about $1000. Key word, dependable.
All my 80s will do 40 mph, but stock Walmart parts only last about 100 miles at that speed. Expect to do a lot of upgrading in the first year.
I think that may be a little exaggerated...
If anything, the engine does aid in the braking process (engine braking).
The bike's wheels (29in) will rotate about just as fast at 40MPH, as a 24in wheeled bike does at 33MPH, or a 20in wheeled bike at 27MPH.
I may want to equip the axis with some thick grease (perhaps lithium grease).