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Path: utzoo!watmath!clyde!burl!ulysses!harpo!seismo!ut-sally!ut-ngp!knutson
From: knutson@ut-ngp.UUCP
Newsgroups: net.auto
Subject: Re: Suspension systems
Message-ID: <552@ut-ngp.UUCP>
Date: Thu, 26-Apr-84 09:02:19 EST
Article-I.D.: ut-ngp.552
Posted: Thu Apr 26 09:02:19 1984
Date-Received: Fri, 27-Apr-84 04:40:22 EST
References: <7368@decwrl.UUCP>
Organization: Comp. Center, Univ. of Texas at Austin
Lines: 23

There are lots of factors at play here.  The most important being mass.
To have a car that is driveable, the wheels need to stay on the ground.
That means lots of movement on bumpy roads.  To do this, you need as
low a mass as you can get for the suspension parts that move (e.g.
wheels, rims, A arms, etc.).  To keep the body from moving with the
wheels, more mass would help but at a disadvantage for maneuverability.
Also, spring rates for the front and rear need to be balanced so you
don't start getting harmonic motion when passing over dips and bumps.
Shocks help dampen this out at the cost of having the motion in the
suspension transfered to the frame.  The stiffer the shocks the more
motion that is transferred.  Note that there is a difference in the
rates for shock compression and extension.  Extension rates are faster
so that when a wheel is picked up, it can be put down on the ground
faster.  Overall the whole situation is a compromise with sports 
cars getting the performance and rough ride and big luxury
cars getting smooth rides and terrible performance.  Most of this comes
from a book called "How to make your car handle" that can be picked
up in most speed shops.  I don't remember who wrote it.

-- 
Jim Knutson
ARPA: knutson@ut-ngp
UUCP: {ihnp4,seismo,kpno,ctvax}!ut-sally!ut-ngp!knutson