On Oct 17, 12:07*pm, Jeff Wisnia wrote:
Someone asked me why their car's front brakes always seem to need
replacing long before the rear brakes do.

At rest, or at moderate speeds, the front and rear tires
bear the same load (that's why you use the same, or
nearly the same, tire pressures front and rear).

When braking, the nonrotation of the car means the torque (by
the wheel/road friction) and countertorque (by imbalance of
front wheel/rear wheel load force) are equal. That
means the front wheels bear more load during the braking
of forward motion than at rest.

Since the front wheels bear more load during braking,
they can safely apply more friction force (and are sized and
proportionally engaged to do so). Higher friction force means
more wear on the front brake parts than on the rear.

Phrases like 'throws weight forward' are suggestive of
the car center-of-mass shifting with respect to the wheelbase.
That doesn't happen. Compression of the front springs
(the hood dips when you brake) is easy to see happening,
and should indicate (to folk who don't do force diagrams)
the front-tire-load situation.