So what is "dangerous" understeer or oversteer? Although under- and oversteer can both cause loss of control, many cars are designed to understeer. It is generally believed by car designers that understeer is easier to control. In fact, almost all cars you drive have understeer built into them.
From a driving standpoint, what is hard to do and considered by many to be a dangerous characteristic, is a vehicle that goes quickly from understeer to oversteer, or vice versa. You hear it often when watching a NASCAR event; they will say that the car was tight (understeer) entering the corner and loose (oversteer) coming out. This condition is one of the very few that will actually cause a NASCAR driver to slow down. >/p>
Causes of Understeer and Oversteer
The causes of understeer and oversteer are usually related to the condition and type of the tires on the vehicle and the vehicle design.
- Low front tire pressure (understeer)
- Low rear tire pressure (oversteer)
- Uneven front tire pressure (understeer)
- Uneven rear tire pressure (oversteer)
- Bald tires in the back (oversteer)
- Bald tires in the front (understeer)
Keep in mind that the correct tire pressure is a function of the weight the tire supports. A special caution for those of you that carry heavy equipment in your trunk: normal rear tire pressures may not be sufficient; you will need to carry extra air in your rear tires to support that weight. Excess weight in the trunk can cause this quick change from under- to oversteer.