Table 3B
Understeer Gradients for SUV Models
with Data Available from Only One Source
Vehicle Model Year Drivetrain Source Wheelbase (in) Data Reduction* Understeer Gradient (deg/g) Standard Deviation** (deg/g) 95% Confidence Interval**
Lower Limit Upper Limit
BMW X5 - 4-Dr. 2001 4X4 Ford     1.7      
Dodge Durango - 4-Dr. 2001 4X4 Ford     2.3      
Chevrolet TrailBlazer - 4-Dr. 2002 4X2 Ford     2.6      
Mercedes-Benz ML430 - 4-Dr. 1999 4X4 Ford     2.6      
Jeep Liberty - 4-Dr. 2002 4X4 Ford     2.8      
Isuzu Amigo - 2-Dr. 1999 4X4 Ford     2.8      
Honda CRV - 4-Dr. 2001 4X2 Ford     3.0      
Toyota 4Runner - 4-Dr. 1994 4X2 Ford     3.2      
Chevrolet Tracker - 2-Dr. 1998 4X4 VRTC 85.6   3.34 0.16 3.34 3.34
Nissan Pathfinder - 4-Dr. 2001 4X4 Ford     3.4      
Honda CRV - 4-Dr. 2000 4X4 Ford     3.4      
Lexus RX300 - 4-Dr. 1999 4X2 Ford     3.5      
Lexus RX300 - 4-Dr. 2000 4X2 Ford     3.5      
Nissan Pathfinder - 4 Dr. 1992 4X2 Guenther     3.56      
Lexus RX300 - 4-Dr. 2001 4X4 Ford     3.6      
Acura MDX - 4-Dr. 2001 4X4 Ford     3.7      
Dodge Durango - 4-Dr. 1998 4X4 Ford     4.3      
Jeep Grand Cherokee - 4 Dr. 1996 4X2 Guenther     4.42      
Chevrolet Tahoe - 4-Dr. 1998 4X4 VRTC 117.2   4.67 0.60 4.67 4.67
Nissan Xterra - 4-Dr. 2000 4X4 Ford     4.9      
Jeep Cherokee - 4-Dr. 2001 4X2 Guenther     4.94      
Jeep Cherokee - 4-Dr. 2001 4X2 Guenther   VRTC 5.26 0.35 4.89 5.63
Jeep Cherokee - 4-Dr. 2001 4X2 Guenther   Ford 4.56      
Jeep Grand Cherokee - 4-Dr. 1998 4X4 Ford     5.4      
Chevrolet Blazer - 4-Dr. 2000 4X4 Ford 107.0   5.5      
Jeep Grand Cherokee - 4-Dr. 2000 4X4 Ford     6.1      
Jeep Grand Cherokee - 4-Dr. 1999 4X4 Ford     6.5      

*  Firestone provided a copy of the raw test data for the vehicles tested prior to May 31, 2001, VRTC staff analyzed this data using the same data reduction techniques used for the tests performed by VRTC, and Ford staff analyzed the data for the Chevrolet Blazer and Jeep Cherokee using the same data reduction techniques used for the tests performed by Ford.

**  The Standard Deviation and the 95% Confidence Interval indicates the statistical variability that results from the different results obtained during individual test runs performed during one series of tests. In the case of the VRTC tests, there were three test runs in the clockwise direction and three test runs in the counter-clockwise direction. In the case of the Guenther tests, the number of runs upon which these numbers are based are shown in parantheses after the Standard Deviation value.