I never planned to push the controller. My discussion about FETs and such is in regards to my experience with brushless engine cooling fan motors which often have integrated PWM controllers... as far as I can tell, in bike applications, the PWM controller is always external so no concerns with the motor from a FET overload standpoint.

Nice suggestion with the wrench as a torque arm. Simple yet effective. I've also seen some stamped pieces on Ebay for less than $20.

I have a rear motor setup so I'll take your suggestion with the torque arm if I move forward with the 72V setup.

53 km/hr would be plenty for me. I'd be happy if I could cruise at 40 kph (25mph). With 36V, I average around 18-20 mph. My 24 mile commute today took me exactly what I expected - 80 minutes. It'd be nice to be closer to an hour, but it's still a lot of fun either way. I'm enjoying the E Bike!