[DeTomaso] Oversteer/Understeer

[Göran Malmberg]

Re: Oversteer/UndersteerThis is the reason different Ackermann is to be used at different speed tracks. 
At full grip 100% Ackermann is the thing to use, at other speeds wher slipp 
enters the picture, the Ackermann should be such that both wheels is "slipprolling"
in the same direction. 
A note here is that "neutral" dosent nessesarley mean that the car (no driver factor) 
is a fast car. It is very easy to adjust a car to neutral by the wrong action. However,
deciding what is right is no easy task. An example, lets say we have a skidpad again
and that the car balanced to zero. Take the car to the track where it uses more 
rearwheel  hp, and it oversteers. We put on larger rear rubber and the car is back to
long corner high speed balance. 

Now, we take the car back to the skidpad, asking another team to test drive the car.
They find the car to be understeering and we ask them to correct the balance.They 
will probabley adjust the rollbar, or anything but go back to the right tire size. 
This means that they end up with to high a rollstiffness balance and therby the wrong
rolldeflection.
Regards
Goran Malmberg 
  ----- Original Message ----- 
  From: Matt Merritt 
  To: detomaso at realbig.com 
  Cc: hemipanter at hemipanter.se 
  Sent: Tuesday, August 28, 2007 11:03 PM
  Subject: Re: Oversteer/Understeer


  The Hoosier radial tires I used on my racing Pantera were said by the manufacturer to grip best with a 7-degree slip angle.  That means the difference between the way the tires were pointed and the car's direction was 7 degrees.  I consider a car to have "neutral" handling when it's relatively easy to maintain the same slip angles front and rear without excessive driver input.  The driver then "throttle steers" the car - increasing or decreasing throttle to add or subtract traction to one end or the other - to maintain that balance.  My 1989 BMW M3 has outstanding balance.  The Pantera, on the other hand.

  MM