Originally Posted by
wolfchild
Speed is irrelevant and doesn't mean anything, just because going fast or passing somebody else doesn't mean that you are a fitter and stronger rider...I don't care about speed.
OP was asking at what speed do you start to get nervous, so yeah, it is relevant to the question he's asking.
The fast I've ever gone was going down a long gradual hill at 66 kph. Plenty scary.