My comment was around experience of a reasonably heavy bike and braking down steep hills. Like I said, its about technique, if you are getting up to 70kmh with

My comment was around experience of a reasonably heavy bike and braking down steep hills. Like I said, its about technique, if you are getting up to 70kmh with bad brakes then you have bad technique. The braking energy dissipated goes up square vs speed, so in that case you brake earlier and keep the speed down. With that said, I have no doubt a large rotor with out heat soak can easily stop a 200kg bike from 70kmh to zero.