Car handling
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A car's handling is a description of the way the car performs, particularly during cornering. Various factors affect a car's handling, but the primary component is the ability of the suspension to keep the tires in contact with the road surface under all conditions. Put simply, if the tires are not touching the road it doesn't matter how the driver turns or accelerates. Other factors include the choice of tires, tire pressures, the car's aerodynamics, the delivery of power to the wheels and adjustments to the alignment of the wheels.
It is usually most desirable to have the car adjusted for neutral steer, so that it responds quickly to a turn of the steering wheel and the rear wheels exactly follow in the tracks of the front wheels. However this may not be achievable for all speed ranges, or while turning under acceleration or braking.
The most common handling failings are;
- Understeer - the front wheels tend to slip slightly and drift towards the outside of the turn. The driver can compensate by turning a little more tightly, but the tires are liable to wear more quickly.
- Oversteer - the rear wheels tend to slip towards the outside of the turn. The driver must correct by steering away from the corner, otherwise the car is liable to spin.
- Body roll - the car leans towards the outside of the curve. This can lead to the wheels on the inside of the curve being lightly loaded with less grip and is likely to contribute to understeer or oversteer.
For ordinary production cars, manufactures err towards deliberate understeer as this is safer for inexperienced drivers. Other compromises might be a choice of better fuel economy over handling, or a preference for a softer smoother ride.
Adjustments to affect handling are
| Component | Reduce Understeer | Reduce Oversteer |
|---|---|---|
| Weight distribution | centre of gravity towards rear | centre of gravity towards front |
| Front shock absorber | softer | stiffer |
| Rear shock absorber | stiffer | softer |
| Front sway bar | softer | stiffer |
| Rear sway bar | stiffer | softer |
| Front tire selection1 | larger contact area | smaller contact area |
| Rear tire selection | smaller contact area | larger contact area |
| Front tire pressure | higher pressure | lower pressure |
| Rear tire pressure | lower pressure | higher pressure |
| Front wheel camber | increase negative camber | reduce negative camber |
| Rear wheel camber | reduce negative camber | increase negative camber |
| Rear spoiler | smaller | larger |
| Front height | lower front end | raise front end |
| Rear height | raise rear end | lower rear end |
| Front toe in | decrease | increase |
| Rear toe in | increase | decrease |
| 1) Tire contact area can be increased by using wider tires, or tires with fewer grooves in the tread pattern. | ||
External links
- Tim Skelton racing (http://www.timskelton.com/lightning/race_prep/suspension/corrections.htm)