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 of adjustment.

– Don Kitch Jr.
Chief Instructor,
ProFormance Racing School

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