Brakes & Suspension / How Tos / Tech

Quick Tech: Oversteer vs. Understeer and How to Correct Both

Oversteer and understeer are terms used to describe steering sensitivity in vehicles. We’re going to introduce you to both conditions, and talk about the ways they can be corrected, if so desired.

You can also learn about it the Top Gear way here.

Oversteer

Rear tire drift is greater than that of the front, and the rear tends to “spin out.” The vehicle will end up closer to the center of the circle because the rear tire drift changes the direction inward.

Or, simply: Oversteer takes place when a car turns more than the amount commanded by the driver.

Oversteer is common in rear-wheel-drive cars and generally caused by a lack of traction at the rear tires.

When you break loose, oversteer is occurring.

Ways to Correct Oversteer

  • Lower front tire pressure
  • Raise rear tire pressure
  • Stiffen front shocks
  • Soften rear shocks
  • Raise front end
  • Lower rear end
  • Install narrower front tires
  • Install wider rear tires
  • Stiffen front sway bar
  • Soften rear sway bar
  • Reduce front negative camber
  • Reduce positive caster
  • Stiffen front springs
  • Soften rear springs

Understeer

Front tire drift causes the vehicle to refuse to turn as sharply as the direction the wheels are pointed. If the wheels and throttle are held steady, the vehicle will make an ever-widening circle.

Or, simply: Understeer occurs when a car turns less than the amount commanded by the driver.

It’s “push” in racing lingo. It’s a natural handing characteristic of front-wheel-drive and all-wheel-drive vehicles. You turn the wheel, but you just go straight. Which is bad.

How do you fix it?

Ways to Correct Understeer

  • Raise front tire pressure
  • Lower rear tire pressure
  • Soften front shocks and stiffen bump
  • Stiffen rear shocks
  • Lower front end
  • Raise rear end
  • Install wider front tires
  • Install narrower rear tires
  • Soften front sway bar
  • Stiffen rear sway bar
  • Increase front negative camber
  • Increase positive caster
  • Soften front springs
  • Stiffen rear springs

Oversteer and understeer are more common problems in racing than in street driving. As such, weather and track conditions, as well as varying driving styles and abilities will also play a role.

Source: Oversteer and Understeer corrections courtesy of Roger Kraus Racing.

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6 Comments

  1. Joseph Brunetti says:

    Enjoy ur articles!

  2. i have experienced an oversteering of my vitz 02 and have had an accident. my car just ended on a flat land on my right. The mechanic told me it was because my wheels were worn out. But my husband told me it was coz of my lack of experience.

  3. Pingback: A Quick Guide to Diagnosing 10 Common Steering Issues - OnAllCylinders

  4. Sexist pig. Ha ha.

    Shameena, It MIGHT be you but, I have a 2012 Chrysler 200 hardtop convertible and at highway speeds it oversteers. I don’t trust my wife, not because of her inexperience as a driver but, with THAT car. I am used to driving it and know how is going to handle but, getting out of one that is not as “tight” in the steering, there COULD be an issue.
    I caution her to be alert if she has to make a quick swerve because it could easily “get away” from her.

  5. Greetings:

    I drive a 2010 Honda Accord, with about a 54/46 Front/Rear weight bias. Car is fully stock, from tire size to roof, and recommended cold tire pressue is 32psi, all around.

    Doing some calculations based on the weight bias, I arrived at cold pressures of 34.5psi in front, and 29.5 in back.

    I’ve driven with these pressures for almost a month now, and my observations are:

    -More responsive steering(car steered responsively enough for me already)

    -Lower rolling resistance – this thing rolllllls more than it did with 32psi all around.

    -Acceleration and braking – about the same as before, but braking more due to aforementioned roll.

    Today, I went out and measured my front and rear coil spring diameters: Front = 14mm, Rears = 12.5mm.

    Now, does that difference in spring diameter mean that I should go back to running equal cold tire pressures, front in rear, since apparently Honda already compensated for the weight difference with different front and rear spring diameters?

    Thanks in advance for your recommendations!

    • Run all your tires on the same psi as the door specs. Pitch, Roll, Yaw. These have all been factored in already with the accord. Know your cars limits and try to stay within those limits. Hope this helps

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