RE: brakes and lonnnng downhills

["Smith, Kirby A" <kirby.a.smith@lmco.com>]

So, your response suggests that Phil should do several high speed stops on
level ground before assuming that his bias is non-optimal.

kirby

> ----------
> From: 	DeWitt Harrison[SMTP:de@aztek-eng.com]
> Sent: 	Friday, October 09, 1998 1:13 PM
> To: 	kirby.a.smith@lmco.com
> Cc: 	quattro@coimbra.ans.net
> Subject: 	Re: brakes and lonnnng downhills
> 
> On Thu, 08 Oct 1998 21:43:00 -0400,  Kirby Smith wrote:
> >[ ... ]
> >I am becoming ever more amazed at the responses to Phil's message.  I
> >thought Phil's question was clear, but perhaps I am influenced by being
> part
> >of the original conversation.  Let me clarify.  Upon reaching the parking
> >lot at the bottom of Mt. Wash., we felt the wheels to see how hot they
> got.
> >The fronts were warm and the rears were _warmer_.  (I've had much hotter
> >wheels from marginal caliper retraction.)  This suggested to Phil that
> >perhaps the brake pressure proportioning valve should have been set up
> >differently after his car's UFOs were replaced.  Thus his question.  I
> >expect Phil will be happy to receive any specific information on brake
> bias
> >setup that can be effected on his 200q if any listers have this
> knowledge.
> 
> Right. The point of the question was largely missed. There is an
> adjustable
> front/rear proportioning valve on many of these cars which responds to
> rear cargo weight - not to disparage Phil's rear seat passengers. The
> valve
> simply has an arm which moves as the rear suspension height changes with
> loading. The point is to better utilize the rear brakes when the car is
> more
> heavily laden since the rear wheels will be less prone to lock up during a
> stop when the front/rear weight bias is moved rearward.
> 
> I think this strategy is geared more toward fast stops on flat terrain
> which transfers most of the weight of a lightly loaded vehicle onto the
> front
> tires, but less of a heavily loaded vehicle. In the absence of rapid
> deceleration,
> a rear cargo load could place a disproportionate burden on the rear brakes
> with this system.
> 
> DeWitt Harrison
> Boulder, CO
> 88 5kcstq
>