Date:         Mon, 5 Jul 2010 08:41:20 -0700
Reply-To:     Don Hanson <dhanson928@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Don Hanson <dhanson928@GMAIL.COM>
Subject:      Re: Parking brake pressure (was I've had it)
In-Reply-To:  <BLU0-SMTP15B3B07D3574353E34147EA6B10@phx.gbl>
Content-Type: text/plain; charset=ISO-8859-1

  Any rear brake that can lock the rear wheels during a straight line panic
stop...that is all the brake you can use.  I've never tried to lock em up
with my vanagon, but I'd bet the rear drums as supplied from the factory
would not do so.
  A "perfect" brake system would cause the front and rear wheels to lock at
exactly the same moment, and to "release" from the 'skid' at the same time,
front to rear.  You see lots of car-nerds putting huge Big Red Brembo
multiple pad perforated rotor aftermarket brakes onto their street/track
cars--front and rear.  Way Wrong!  Any brake that is larger than what will
lock the rear wheels, that gives negative performance...more weight, no more
stopping power.  Once your tire has stopped rotating and began sliding you
gain nothing-nothing by being able to apply more force to the wheel....it is
already stopped....you can not stop it ...more than stopped.
  "Better" brakes at the rear, brakes that are quicker to react, more
sensitive to minute changes in hydraulic pressure and less susceptible to
heat build up... but that are as light as possible, that is what you are
looking for to actually improve the braking of any vehicle.
  Back in the day, the British made some motorcycles with 6 leading shoe
front brakes...Fun to adjust those....but they were quite a bit more
responsive and fade resistant than the rest of the brakes available at the
time...The rear brake on those bikes....BSA Rocket, I think, they were
tiny...and you could still lock up the rear with no problem under hard
braking..
  Braking is all about traction.  4 tires touching the road...4700lbs of
weight , divided amongst  the four tires.  Panic stop, most of that weight
shifts onto the front tires and the rear tires want to lift off, almost.
  Don hanson

On Sun, Jul 4, 2010 at 11:43 PM, Karl Wolz <wolzphoto@q.com> wrote:

> At least part of it is marketing.  There is a perception that rear disks
> are
> vastly superior to drums and those cars that have disks are inferior - just
> ask my son!
>
> Karl Wolz
>
>
> |But if you want my bet as to why cars are being built with rear disk
> |brakes (leaving aside race cars) -- I suspect it is purely cosmetic.
> |
> |Yours,
> |David
>