Re: Curves and manual transmissions

[Roger Haar <haar@PHYSICS.ARIZONA.EDU>]

Hi,
        Just a couple of semi-educated guesses.

1. . Usually when going through a curve one starts
to push down on the throttle to start increasing
speed after about the midpoint of the curve.Being
in a lower gear probably means one will have a
greater rate of increase in the cars speed thus
feeling like the car is really scooting through
the curves.

2. Once the throttle is depressed coming through a
curve, the  greater rear wheel torque will causes
some transfer of the car's weight to the back.
The lower the gear the greater the transfer.

3.  In stock car racing, the front wheels are
parallel with the car through most of the curve
with the exception of starting the turn.  The cars
go around the curve because the back tires are
starting to get loose on the pavement and the car
is "oversteering"  The more power the more
oversteering.

4.  People who race front wheel drive cars do a
thing called "trailing braking" in which they
maintain the throttle at a middle level even as
they are braking into a curve and to the midpoint
of the curve.  The competing forces on the frame
and suspension system pulls the suspension system
tight so there is no slop.  The result is that the
steering is very responsive and predictable.  Even
on rear wheel drive cars, if the is a lot of
torque on the rear wheels (from being in a lower
gear at full throttle) the suspension might well
tighten up.

5.  We physicist, often one to apply vary simple
models to complex things like tires on pavement
and how the load will be distributed on the four
tires.  It is actually rather complicated, even
before one adds interesting feedback to the
suspension system like antiroll bars.  In some
current models the car will take over the brakes
and throttle to stop a slide.

Thanks
Roger Haar

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"Gonzalez-Espada, Wilson" wrote:
> Hello all:
>
> Yesterday, a student of mine commented the following: He argues that when his car takes a horizontal curve with a certain speed and a lower gear (manual transmission) the car "handles better the road" compared with taking the same curve at the same speed but on a higher gear. Any explanations for this? I know that "handling of the road" is not a scientific observation but he argues that he has asked other people and they have experienced the same.