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Re: suspension/traction question

To: John Burk <joyseydevil@comcast.net>
Subject: Re: suspension/traction question
From: Dave Dahlgren <ddahlgren@snet.net>
Date: Fri, 17 Oct 2003 05:25:17 -0400
Why would the down force always average 1 g other than standing still?? I would
think the down force is relative to the surface condition, the aero loading
either + or - depending on aero devices and body configuration.
Think about the dynamics of hitting a bump for a minute. Things to think about
are the size and shape of the bump to begin with. Suspended or not any bump has
to slow you down for at least 2 reasons. First is the time and distance that you
do not have traction as good as before you hit it. The second is the force
vectors involved. These would be a function of the slope and shape of the bump.
The taller and steeper the angle the greater the vector pointing back to where
you started from slowing the car down.
The 1 g landings and take off you talk about i do not understand as well. The
stiffer the car the higher the g loading from what i can see. With a solid
suspension I don't see why you couldn't easily generate 10 g's to be honest. G
loadings are all about time and distance. To reduce them you have to add time to
travel the distance. Picture jumping off a 10 story building and either hitting
the street or a big air bag.. same distance to go but more time to decell.
Suspension reduces the g loading that is why the ride is more comfortable and
damage to the wheels and tires is less when you hit a bump. If there were no
change in the loadings there would be no perceived increase in driver comfort.
These reduced loading would also imply that the forces when hitting a bump would
be less with a proper suspension would that also imply that the forces in both
the up direction and the vector point back might be less as well??
Dave
John Burk wrote:
> 
> Hi Dave - There's no question that tires at Bonneville get there share of
> air time , less of it with springs pushing them down - My question is , with
> the down force always averaging 1 g and unsprung weight being maybe 20% how
> much faster is a sprung car -    John





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