[net.auto] squeaky brakes

bcbell@inmet.UUCP (10/26/85)

** Brake line (revisited) **

There are a couple of reasons you may not see as much brake dust accumulation
on the rear wheels of your GTI as the front.  The first is that the brakes are
biased front to rear so that the front brakes do more of the braking.  This
is because, as a car decelerates, the moment of inertia moves toward the front
of the car.  So the front brakes are sqeezing harder, and more pad wears off.
The second reason is the airflow around the wheels is (probably) different for
the front and the back.  It's doubtful that anyone calculates that sort of 
thing for passenger cars, but if the airflow around the front wheels blew out
while it blew in in the back the backs would be forever clean while the fronts
would certainly be dusty.  Note that virtually ALL cars have front disk brakes
and most don't have brake dust problems.  Note also that alloy (i.e. holey)
wheels tend to get the problem worse that others do, if for no other reason
than the holes allow airflow through the wheels.

R.M. Mottola
Cyborg Corp.
Newton, MA.

gvcormack@watmum.UUCP (Gordon V. Cormack) (10/29/85)

        ...  ...   the brakes are
> biased front to rear so that the front brakes do more of the braking.  This
> is because, as a car decelerates, the moment of inertia moves toward the front
> of the car.  So the front brakes are sqeezing harder, and more pad wears off.

We have been over this recently in the context of "weight transfer"
on cornering.  The moment of inertia (aka centre of gravity) doesn't
move ANYWHERE during braking.  There is, of course, weight transfer
(weight == the downward force on the wheels) from rear to front on
braking, so otherwise the posting is correct.