One of the reasons, probably the main reason, why just stamping on the brakes does not work is that if you lock the front wheels immediately you do not get the weight transfer to the front. The reason why disk brakes are used at the front of cars (or more powerful brakes in the case of all disk cars) is that the front tyres and brakes give the main stopping forces. This is because in correct braking a very high proportion of the weight of the car is transferred to the front wheels. You see this more clearly with a motorbike when the front of the bike dips under braking.

The correct braking procedure is to increase pressure on the brakes in a controlled way so that the weight of the vehicle transferred to the front places more downward force on the front tyres thereby increasing grip due to a combination of the forces and the increased contact patch. As the weight transfer takes place you can increase the force on the pedal until the moment that the tyres are almost losing grip. At this point you need to adjust pressure to keep it at that point.

I don't do it as often as I should but I highly recommend that those without ABS should practice this on a quiet road from time to time. If you do this often enough in an imagined emergency stop your brain will automatically take over in a real emergency and you will have a much better chance of minimising or avoiding the accident.

This has been previously covered on the forum but the video below shows that the wheels were well and truly locked up before impact.


Peter

[Linked Image]