I learned how to ride in the early 80's in central FL... (Brooksville - There are curves in FL)
A posted 35- 45MPH curve is easily doubled and most turns in FL you can triple the posted speed.
Here in Western NC most curves are not posted unless really bad.
Example which most of you who have visited here know, is the 10mph right turn on 28 heading west towards the Deal's Gap store.
On the C-14 it can be taken at 35-40mph on an 848 it can be done at 60mph without dragging a knee.
The speed limit on 28 from Franklin to Deal's Gap is 55mph. There are places where it is impossible to hold 55mph and there are no signs.
Much like Deal's Gap, some places you can not hold 30mph and that road used to be 55mph.
As far as posted speed, I think all states are way off on their posted safe speed.
But, remember that the posted safe speeds are set for vehicles like large trucks.
A yellow sign is a warning, a white sign is the speed limit. So you can take a 35mph turn at 55mph without it being illegal.
It would be nice if more drivers and riders knew this.
One problem here is the NC State speed limit is 55 unless otherwise posted.
So a Harley rider sees a yellow sign with 35 on it leading up to a curve, then they ride 35mph for the entire stretch of the road.
It is really bad when they have 6-10 pirate ships all wobbling down the yellow line at 35mph... And no passing zone is available...