Re: 45mph at ~7600rpms
Grats!!! Your speed is completely believable. I hit a top speed of 39.7 MPH (GPS verified) on flat ground with my BGF RB80 on my Cranbrick with 36T rear and no internal mods. I REALLY wanted to hit 40 but never could tuck down quite enough (or stop shoving cheeseburgers in my face long enough) to quite make it.
Then my wrist pin bearing went kabloooie!
Grats again, and looking forward to you hitting 50! I thought going nearly 40 on an motorized bicycle was exhilarating, I could only imagine what 50 is like. Hopefully you have some good brakes!