Date: Mon, 16 Jul 2007 23:10:19 -0700
Reply-To: Don Hanson <dhanson@GORGE.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Don Hanson <dhanson@GORGE.NET>
Subject: More brakes.
Content-Type: text/plain; charset="Windows-1252"
80% of braking comes from the front..that's of course, a generalization that
comes from simplistic textbooks on driving, etc. For a Van, with it's high
center of gravity, it'd probably be even more during a panic stop. Someone
mentioned their van's 'nose-diving' under hard braking..That is the
Vanagon's high center of gravity, for one thing..Think about that
behavior....the nose diving. That is exactly why so much of the total
braking force comes from the front tire contact patch..as the nose dives,
the rear lifts, or 'un-weights' and there is almost no weight on the rear
tires..No weight=no traction.. No traction=no real braking force...
That is the main reason why braking while in a turn is not a good
idea..Your 4 tires are holding you to the road ok, but if you brake, the
weight shifts forward onto mainly the front wheels , causing the back end to
let loose...A vanagon is not so bad when this happens, with it's almost
equal mass, front and rear...A rear engined Porsche or VW....not good to get
that big lump of weight, hanging out beyond the rear wheels, going
outwards....
There is not much to be done about the high center of gravity on a van,
or the nose diving, if you want to keep the fillings in your teeth while
driving. You can stiffen the suspension, I suppose, but that only makes the
weight transfer come quicker and a bit more predictably..You could lower the
C of gravity, but that would defeat the whole Vanagon idea..Besides, it's a
Van, not a sporty car..
Best idea, in my opinion, is to just install some more powerful front
brakes and find the best bias adjustment between front and rear, then keep
in mind that you're driving a Tall vehicle that will never be a performance
vehicle...When and if you lock the brakes, you will have to 'pump' em
yourself without ABS..because when you lock up your wheels, your braking
force becomes very diminished..Right at the very edge of locking the wheels
is where you'll get the most slowing of your vehicle.
Don Hanson
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