About Understeer & Oversteer
August 3, 2011 Leave a comment
Even if you don’t know exactly what understeer or oversteer are, you’ve certainly experienced one or the other at some point driving your vehicle. Understeer is when the front of your vehicle has less than adequate grip, and the front tires scrub outwards toward the outside of a turn. This can happen if you carry too much speed into a corner, or if the road is slick and the front tires don’t have enough grip to turn the front of the vehicle. Oversteer is just the opposite, when the rear tires don’t have enough grip and lose traction, causing the rear of the vehicle to rotate or spin. Some call this powersliding or drifting, either way it will slow your car down and is a result of poor suspension tuning or too much power going through the rear wheels of a RWD car. Both of these effects can be tamed with proper driving techniques, but too much of something is never good, and both of these conditions can be reduced with proper suspension tuning.
Most factory cars are tuned to understeer at the limit, as understeer is usually less dangerous and easier to control than oversteer. In a situation where your car is understeering, lowering your vehicle speed by letting off the throttle can reduce the effects, or if you are an experienced driver, giving some throttle can promote oversteer and balance the car’s angle. The main reason for understeer is too much weight over the front wheels, which is why cars with a 50/50 front rear weight balance are considered to be some of the best handling cars out there. When it comes to tuning a car for neutral handling characteristics (same amount of understeer as oversteer), there are many things you can do such as adding negative camber up front, stickier tires, or even stiffening the rear suspension to make the car more prone to oversteer. The key to tuning a car properly is balance, so upgrading everything just to say you have done so isn’t the best approach.
You first need to learn your car and figure out how it reacts when at the limit. Everyone’s driving styles are different, so someone with a heavy throttle foot may experience more oversteer in a car where someone else could cause the same car to understeer under certain conditions. The best mod you can do to a car is learning how to pilot it correctly, once you learn your car you will be able to account for it’s flaws and really drive it at the limit comfortably.
Below is an older video of Top Gear’s Tiff Needell explaining these concepts in depth.
Since most oversteer in RWD cars is caused by too much throttle application or poor weight distribution, there isn’t really much needed in terms of upgrading other than adding stickier tires to add grip out back. However there are some situations when improper suspension setups can cause a car to be too tail-happy, such as a rear suspension that is way too stiff and a front suspension that is too soft. In these conditions, going into a corner too fast will cause the rear to rotate around and can cause you to spin. Of course, the experienced driver will use counter-steer to correct oversteer and avoid a spin, but those without quick reflexes or experience with oversteer could lose control and spin or even worse, crash. If you feel your car is too quick to oversteer, adding a front sway bar to stiffen the front will help with this. Again, too much of anything isn’t good when it comes to suspension tuning, so finding a good balance is key.
Mustangs tend to have more weight over their front wheels than the back for obvious reasons, a big engine up front and little weight out back makes it a prime candidate for understeer, but with the torque the engine creates, just blipping the throttle mid-turn will cause the rear tires to spin and voila- oversteer. Another issue with Mustangs is their heavy weight and the fact that they were tuned for road comfort, causing body roll in corners and making it hard to control the weight transfer in corners. This is why adding a lower, stiffer suspension is so popular. It gives the driver the added confidence to use the throttle as a tool to promote oversteer. If you’re driving a big heavy car with lots of body roll in corners, you most likely aren’t going to be comfortable giving it throttle to promote oversteer, because this can be a scary thing in a car without proper suspension tuning.
A few simple mods you can do to reduce understeer or oversteer:
Too much understeer:
-Stiffen rear suspension-
-Upgrade rear sway bar-
-Install wider/stickier tires-
-Reduce weight in front of vehicle-
-Increase negative camber up front-
Too much oversteer:
-Stiffen front suspension-
-Upgrade front sway bar-
-Install wider/stickier tires-
-Go easier on the throttle!-