You get weight transfer to the front. In steady state constant speed with
the engine driving force is applied by the drive wheels to make up for
mechanical and aerodynamic losses. When you remove power the direction of
the force vector reverses as drive line parasitic drag is applied through
what used to be the drive wheels. Drive force is acting below the center of
gravity, the car is not rotating in the pitch axis, and the moments must be
balanced. In the first case there is weight transfer from front to rear and
in the later from rear to front. The moment the wind resistance works
through doesn't matter since it's the same in either case and we're looking
at what happens in a relative sense when you put in the clutch.
Now if you had a rocket car with the thrust centerline above the center of
gravity, the oposite would occur. ;-)
--- Rick Brown
-----Original Message-----
From: owner-autox@autox.team.net [mailto:owner-autox@autox.team.net]On
Behalf Of Antoun Nabhan
Sent: Friday, December 17, 1999 9:14 AM
To: autox@autox.team.net
Subject: Weight Transfer Question
My roomate and I were discussing this last night in the context of
high-speed tire failures, and I need the wisdom of team.net.
If you are driving at a steady speed (okay, I know we're *always* supposed
to be either accelerating or braking!) and remove engine power, by putting
the car into neutral or putting in the clutch, do you get weight transfer
to the front wheels?
At a steady speed the engine is "accelerating" the car against wind &
rolling resistance, so maybe yes. On the other hand, the vector of wind
resistance doesn't necessarily act above or below the center of gravity;
conceivably you could transfer weight to the *rear* wheels by letting out
the clutch if the car had more resistance above than below. Or...well,
three or four other possibilities suggested themselves.
What's the real deal? Push in the clutch or maintain steady throttle on
blowout?
----------------------------------------------------------------------------
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Antoun Nabhan * Twelve months of racing, Eleven hours of sunlight,
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