Listen to a driver discussing the behavior of his car with friends, engineers, media, anyone — and two terms are always thrown around. Those words, describing the way in which a car breaks traction at the limit, can have both drivers and engineers scratching their heads for hours, trying desperately to figure out what exactly is exacerbating their car’s wayward handling. Most people reading this article have a general idea of what oversteer and understeer are, and can cite the odd adage, but seldom are the specific benefits and hindrances of these two states explained.
Understeer, on tarmac, is possibly the safer way to get through a corner. With understeer, one merely has to release the throttle, dial back the steering lock, and if it’s looking terminal, dab the brake. It can be frustrating, but it has certain benefits which can serve a driver with a macro-view of the race — namely, consistency and tire conservation.
Understeer might sap time here and there, but in quick corners, it’s typically the most consistent, if not the fastest way. Alain Prost, a driver who seldom made mistakes, always insisted that a mild amount of understeer was ideal. However, he was occasionally outpaced by drivers who preferred a car with a “loose” rear. Oversteer is quick, but it’s less consistent, risky, and detrimental to the tires.
Consider a huge tailslide in the middle of a corner at 100 mph. First of all, it’s a risky endeavor. Unless one’s car control is top-notch, there’s a very good chance it won’t end well. Secondly, and more objectively, it’s a surefire way to destroy a set of tires. High-speed sliding puts plenty of strain on a set of rubber. Lastly, it doesn’t serve well in terms of probability. Even if one is capable of holding a big slide a few times, chances are that change in surface condition will eventually catch them out. For this reason, oversteer is risky, but it can be the quickest way through, if a driver is very talented.
But often, these two states blend over into one, and it gets hard to diagnose. When a car is pushed hard into a corner and the driver, with a handful of steering lock, has to wait for the understeer to diminish, they often get frustrated. Often, amateur drivers push hard into the mid-corner phase, only to try and mitigate the plowing with a bootful of throttle. While this will get the car pointed in the right direction, it transfers load so violently, that it often spins the car. This is referred to as “push-loose” in NASCAR terminology, or “snap oversteer” in most other realms. This confuses the novice, who thinks they have an oversteer issue, when in reality, they couldn’t transfer load smoothly enough from front to rear to really uncover the car’s handling traits. Managing understeer and oversteer requires a certain amount of patience.
Any driver flirting with the limit will become comfortable with both states. To chase the quickest lap time, they have to be able to improvise with the machinery. Some drivers, particularly young fighters, love to chase a nervous rear end, sliding to-and-fro in an acrobatic fashion, bouncing over curbs in pursuit of pole position. However, some drivers love the stability and consistency that understeer offers, and while it might not offer as much adjustability, it is a great way to ensure race pace, assuming the driver knows how to control it. Every driver has their own preference, but understanding the objective truths behind both states of sliding will help inform setup changes, and hopefully keep the repair bills low.