Date:         Wed, 10 Sep 2008 21:58:59 -0600
Reply-To:     Andrew Grebneff <goose1047@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Andrew Grebneff <goose1047@GMAIL.COM>
Subject:      Re: Tire pressures..why
Content-Type: text/plain; charset=ISO-8859-1

At 05:11 PM 30/07/2008, you wrote:

    It's a liability thing, pure and simple.  Vehicle manufactures have
  figured out that a car they sell to the public MUST understeer in =
order for
  them (the car maker) to avoid lawsuits in the US..So they spec. a tire
  pressure that will cause understeer, even if a vehicle is capable of =
100%
  neutral handling.  Then, when "Joe-average driver" goes into a corner =
too
  fast to have a hope of making it....The front end understeers and the =
car,
  truck, van, whatever plows right off the outside of the corner and the
  accident report will read something like "Driver drove off the road, =
going
  too fast"..

    You may recall some oversteering vehicles from the past, such as the
  Corvair or some of the Air cooled Porsches...Get into a corner too hot =
with
  one of those, and the rear end came around ("Oversteer")..Those =
accident
  reports probably read  "Lost control of car, spun off the =
road"...causing
  the legal vultures to jump in and blame the car maker for building a =
car
  that spun out...(no matter that that car was operated stupidly)

    So, we get almost all cars with built in understeer, or when they =
don't
  have it built in, like perhaps a Vanagon (dunno, I am not brave enough =
to
  take my Vanagon onto a road circuit and try it out at 4-wheel drift =
speeds)
  then the manufactures specify a tire pressure that will cause it to
  understeer...thus covering their a++es from lawsuits..

    Don Hanson


That too! US cars are not made with handling at all in mind (I don't =
think the US divisions of the manufacturers even know what handling is, =
and I know that some listees don't)... this includes such things as =
Vipers, Mustangs etc. If they can oversteer at all it's =
torque-oversteer, not due to chassis dynamics. These cars are made with =
steering/suspension geometry flaws built-in, and I very much doubt than =
any amount of tire, wheel, spring, damper, swayba or adjusting can make =
them go around bends.

US-market cars from nonUS manufacturers have suspensions severely =
detuned to give the cushy ride so beloved of Florida retirees. Soft =
springs, skinny swaybars and almost no damping. The only exception I =
know of is the VZ Holden Commodore (currently sold in the US as =
"PontiacG8" and Saudi Arabia as "Chevrolet Lumina"; previously the =
VT-generation coupe version was sold in the US as "Pontiac GTO"), which =
Holden decided to market there with stock ie not detuned suspension.

In Europe the VW T3 has a great reputation for handling, being basically =
neutral (with ability to oversteer if fitted with a decent [and =
not-too-heavy!!] engine). See some of the links in the recent Vanagon =
Crash Test posting for videos of just how fast the T3 can corner with =
decent suspension settings.


--
Andrew Grebneff
Dunedin, New Zealand
Fossil preparator
Mollusc, Toyota & VW van nut
Temporarily in Calgary, AB, Canada