doughpat wrote: How fast would you say a reasonable person (with dependents!) should try to go on this bike?
How good are the brakes?
How well does it stop from various speeds, meaning how controllable is the stop under various conditions?
That's probably your most important limiting factor--if you can't stop safely and easily from a certain speed, you probably don't want to be going that fast.
If you're not sure, try testing it out on downhills without any traffic, etc., with straight stops, stops while turning, etc., and see how it works from various speeds, both with sudden stops and slow decelerations, etc. I recommend good thick multilayer clothing and/or joint padding and a good helmet for this kind of testing.
The good news is that most typically a crash (for me) at speeds below 40MPH on CrazyBike2, like when I was on the racetrack for the Death Races in Tucson, it results in a sideways skid, rather than an endover, but that depends on the reason for a crash.
But if i'd been unable to stop quckly enough and rammed into a car or whatever in front of me, most likely it'd've been an endover and I'd've been launched into the air at a high speed over or into whatever I'd hit. That kind of crash is likely to only happen below 20MPH for me becuase that's the speed limit here, but I don't know how fast you'd end up going or what the limits are there.