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Laboratory performance testing of larger tires requires system capability beyond larger diametric clearance and additional radial load capability. This paper describes a newly introduced Flat-Trac® tire test system designed for light truck tires and racing tires. Background on flat surface force and moment testing identifying the need for a system with more capability is presented. The MTS Flat-Trac LTR tire test system is introduced as a force and moment measurement system capable of testing light truck and racing tires. The first of these systems has been in operation at Bridgestone's Tokyo technical center since July 2002. Test results are presented to show that the Flat-Trac LTR (Light Truck/Racing) provides increased capability beyond the conventional Flat-Trac III CT (Cornering and Traction) system. Cornering force and longitudinal force test results are compared to show agreement between the Flat-Trac LTR and Flat-Trac CT systems.

The intention of this work is to illustrate a method used to overcome limitations of tire models developed during an evaluation study of an Empirical Dynamic™ (ED) damper model. A quarter vehicle test system was built to support the evaluation, and a model of the test system was also developed in ADAMS™. In the model, the damper was represented by a polynomial spline function and by an ED model separately. Vehicle level comparisons between the physical measurements and the model predictions were conducted. The actuator displacement signal from the physical test was used to drive the virtual test system. Spindle acceleration, spindle force, and other signals were collected for comparison. The tire model was identified as a significant source of error and as a result, the direct vehicle level correlation study did not illustrate any advantage of the ED damper model over a spline damper model.

This paper documents the process used to correlate the secondary belt degradation experienced on the test track with the secondary belt degradation experienced during laboratory tests using a Secondary Drive Test System. Two different software products were used to produce this correlation: nCode's pseudo-damage functionality was used to estimate the proportional belt degradation and MTS's RPC Pro functionality was used to edit the field data, create a time history file, and to shift the frequency domain of the vehicle into the usable range of the servo-hydraulic actuator (time stretching). For purposes of this paper, the test data and information presented in this paper is based on two different secondary drive belts that were used on the test track as well as in the laboratory tests. As will be shown, the plot information that resulted from these tests showed very good correlation.

The wheel force transducer has been proven to be a cost and time effective tool for vehicle load data acquisition and simulation testing. The accuracy of wheel force transducers is typically given in terms of a static calibration, or a quasi-static system generated load case. The actual use of a wheel force transducer often involves high speed rotation, varying camber and steer of the tire on the vehicle, and other dynamic and rim related variations which deviate from the standard laboratory calibration. The Flat-Trac proves to be an excellent tool in the design process and evaluation of the wheel force transducer because it accurately controls and simulates the loading of a rotating wheel assembly. Through Flat-Trac System testing, issues that are critical to the use, accuracy, and integrity of data acquired through a wheel force transducer can be evaluated.