And developing that a little more, the resulting vertical velocity is proportional to the sideways velocity. On a motorbike, the sideways velocity can be sufficiently high that the resultant vertical velocity is enough to eject the rider from the bike. I don't think we get up to those sort of speeds on a bike, so I reckon a high-side on a bike is highly unlikely, if not impossible. And, as a couple have already pointed out, the wheels would probably pringle or the tyres slide off at that level of force.I've always been of the view that the vertical component of the rider's velocity is a result of the bike rotating around the sticking point. When the tyre 'sticks' the bike is going sideways and it is leaned over. As it sticks the bike (with rider) rotates and that introduces a good deal of vertical velocity to the rider. Suspension might add to this effect.