Re:IU & Brakes

[mike tipton <mtipton@netten.net>]

With all this discussion of brakes working, and brakes not working. 
Brakes designed to stop 1200-1600hp...

Something that is taught at most advanced driving school, is,

"That brakes dont stop a vehicle. Brakes stop the wheels from turning!
The only thing in contact with the ground, are the tires. With this in 
mind, tires stop a vehicle, brakes stop the wheels from turning." When 
the wheels lock, the law of physics takes over, and your just a mass of 
weight moving in a certain direction. You need the wheels turning to 
control your vehicle, especially in a turn! 

The inertia of a rotating wheel & brake rotor, take energy to slow down
or stop rotating. Brakes being a "friction device" are designed around a 
certain vehicle's weight, hp, and max operating speed. Thats why "race" 
cars have bigger brakes & calipers than street cars.(speed)

 At speed, what is the rpm of the wheel? Combine this with the weight of 
the vehicle, and you can get an idea of what the brakes must do to slow 
a vehicle.
 
Brakes biggest enemy is heat!  Too much will fade brakes fast. With a 
wheel spinning at WOT, how fast is this threshold reached?

Now throw anti-lock into the picture!

"The motive force available at the drive wheels increases as the engine 
torque increases" (SAE)

"Maximiun brake effictiveness is imposed by the static friction between 
the tires and the road, while the lower limit is established by legally
prescribed minium values."(SAE)

 Audi's being German, fall under ECE regulations(UN Economical Commision 
in Geneva)

To figure this all out we need some geometry majors! Or a good book 
about braking system. But it looks (in my opinion) that brakes can 
become "ineffictive" in "stopping" a vehicle, in certain situations.

                 Food for thought!

                                    M