No car is an island. Its handling is a
complex combination of its chassis, tire and aerodynamic
setup, and the infinite possible personalities of the
human clutching the wheel.
In analyzing handling, it is often important
to separate the car’s natural characteristics
from the driver inputs. The best way to highlight this
distinction is to take your What, and put it When and
Where. Think of every corner in terms of entry, middle
and exit, and the speed of the turn. Most handling issues
appear in only one part of the corner, not all the way
around, and this is your best clue to improving it.
The middle of the corner is the best place
to judge your spring and swaybar setup. The entry is
highly affected by brake bias, wheel toe-in and shock
settings, especially front compression and rear rebound,
because weight is transferring forward as you slow.
The exit is influenced most heavily by the differential
in the drive axle, and by shocks-but now it’s
the front rebound and rear compression, because weight
is shifting to the rear under acceleration. And further,
the faster the corner, the more important are the aerodynamic
settings, if your car has them.
A smooth, fast driver will affect the
middle very little. There will be minimal steering input,
and only enough power to hold a speed-maintenance throttle.
Pure cornering. If the car is not turning enough-understeering-stiffen
the rear or soften the front springs or bars. If it
is turning too much-oversteering-stiffen the front or
soften the rear, depending on whether the car wants
to be firmer or more compliant overall.
Shock adjustment is a true art form, and
the best way to compensate for a specific driver’s
style. Multi-adjustable shocks are becoming more common
at all levels of autosport. Rebound shock damping slows
weight transfer, compression speeds it up.
To generalize, adding rebound will normally
cause that end to break away later, and compression
will make it slide sooner. However, there are no absolute
rules, because it depends on where you are in the window
– Don Kitch Jr.
ProFormance Racing School
Reprint at the permission of the author only