Sure-grip cone style driving characteristics ?

AJ/FormS said
When that happens, everything just stops turning, and you are skating; best rear brakes ever.

Did that at 45 mph with a 70 Ford F250. Full rear end lockup, starts getting sideways, all the time my brain was trying to process what the hell is going on. Shaft brakes and rear freewheels. Streightens up, coast into gas station.

30 seconds earlier I was doing 70 on the Fwy.