I have to agree with Gyrobob about retaining the front brake. Accurate modern stats are hard to determine. Here is a stat from about 1928 which did apply to cars 20 mph rear wheel brakes 37 feet all wheel brakes 16feet. 30 mph rear wheel brakes 83 feet, all wheel brakes 36 feet. 35 MPH rear wheel brakes 113 feet, all wheel brakes 49 feet. 60 mph rear wheel brakes 333 feet all wheel brakes 144 feet. S40 rears are prone to locking in harsh stops.