Understeer Versus Oversteer

I’m working on a driving presentation for a local auto dealer, and I remembered these two videos (one from Top Gear, and one inspired by Top Gear) that explain the basics of understeer and oversteer far better than any fifteen-minute, physics based lecture. In a nutshell, when your car understeers, you see the tree that kills you. When you have oversteer, you don’t see it: hence, oversteer (at least according to Richard Hammond) is preferable.

In the real world, especially with modern stability control systems, things aren’t quite this simple. In fact, it’s quite difficult to get cars to do either with modern techno-nannies onboard, especially when some manufacturers (Volkswagen, for example) don’t allow you to fully disable their stability control programs. Other automakers (GM and Chrysler, for example) allow partial or even full defeat of stability control systems for track driving.

The simplest way to counter understeer is to do less of what you’re doing (like turning the steering wheel) to let your front tires regain traction. Excluding a mechanical failure or road condition like oil or ice, oversteer is almost always caused by driver error. Enter a turn too hot, lose your nerve and lift off the throttle (or worse, hit the brakes) and chances are you’ll experience the joys of lift-throttle oversteer. Drive a rear-wheel-drive car and get on the power too early, and you’ll get to experience throttle-on oversteer. Both are easily corrected (and plenty entertaining) in the right environment, which is why we’re big fans of driving schools and high performance driving events (HPDEs). Enjoy the videos below, and hit up the NASA website to see when the next scheduled HPDE in your area is.