"Jim Stewart" wrote in message
news
Jeff Wisnia wrote:

Someone asked me why their car's front brakes always seem to need
replacing long before the rear brakes do.

I started to give him the old "inertial weight transfer to the front
while braking" reply and then found that it really wasn't making total
sense to me.

Providing you don't drive and brake like a madman neither the front or
rear tires are doing much skidding on the pavement so it's likely all
four are all making the same number of revolutions while braking. So, if
the brake pad areas and the piston diameters were all equal front and
rear I'd expect the pad wear rate to also be equal.

It's been too long since I've done a DIY brake job and I never stopped to
study the relative sizes of drums, shoes, pads and pistons back when I
used to do that stuff on all our family jalopies.

The braking system is designed to give the
front brakes more authority than the rear.
The increased pressure and heat causes them
to wear out faster.

And that goes back to the weight transfer
issue. The front brakes get more authority
because they can use it without breaking
traction.

I seem to remember something called a "proportioning valve", between front
and rear brakes.
--
DT