Evaluating Basic Handling

What Do You Feel?

All of us have opinions on how our cars handle. It can be difficult some times to express what our car is or isn't doing when describing a problem we are struggling with. This article will address the basic handling trouble spots so you can easily identify what your car is doing and some general guidelines on what you could do to possibly correct the trouble.

Cornering

UNDERSTEER: Entering a corner our car can exhibit several tendencies, the most common is understeer. It is that sickening feeling you get when you rack your car into a turn and the front wheels slide or "push" instead of following the turn path you had in mind. Most factory cars are set up by design to understeer. It is a compromise that engineers and lawyers came up with so you wont "hurt yourself", and it is very prevalent on classic cars. The diagram shows what is happening. The radius of turn which the car can accommodate considering available traction & speed is greater than the radius of the road or track corner.

• Symptom: You turn the wheel but the car wants to go straight as the tires scrub along the paving.
• Possible Corrective Actions:
  • Camber angle - more negative
  • Anti-sway bar - Add or resize.
  • Ride height - lower.
  • Center of Gravity - lower
  • Tire pressure - lower (down to the safe limit, never under inflated)
  • Tire size - wider, lower profile.

OVERSTEER: Just as you would imagine oversteer is the opposite of understeer. It can be tricky to manage using driving technique since the rear end of the car wants to swing out forcing the driver to take quick action. Those actions are usually to turn in the direction of the skid, reduce the throttle but not completely off, or the slight application of brakes to avert a complete spin. These actions are a learned response and take practice to balance the forces so the car stays in control. 

• Symptom - You turn and the front end has greater traction than the rear and the rear end swings out in the direction of the corner.
• Possible Corrective Actions:
  • Camber angle - less negative
  • Anti-sway bar - resize.
  • Tire pressure - increase (incremental up to max allowed by manufacturer)

NEUTRAL STEER: Just like Goldie Locks we are looking for steering feel that is "just right". A car set up for neutral steer will be the quickest through a corner. It will follow where you point it which presumably is where you want it. It is an elusive setup since there are many variables not the least of which is speed. At higher speeds your vehicles aerodynamics start to play a bigger roll in steering response. A car can go from understeer to neutral to oversteer just with changing the speed but as a general rule the neutral steer set up is the most desirable because it is the most predictable.

• Symptom - Great feel and command of the direction the car is pointing at any given instant.
• Possible Corrective Action - You're kidding right?

Now the next time you are trying to explain what your car is doing, or not doing in a corner you will have a vocabulary that will allow you to explain it terms which someone skilled in the art of chassis setup can advise you.