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Data envelopment analysis (DEA) is used to examine the efficiency of 74 front wheel assist agricultural tractors from three U.S. manufacturers. The outputs of drawbar horsepower and power takeoff horsepower are modeled in a constant returns-to-scale framework using three productive performance inputs (fuel consumption, slip, and center of gravity), and one price input, namely, retail tractor price. The results suggest that by and large, John Deere tractors are more DEA efficient than their competitor's tractors. However, competitor's tractors that are DEA efficient are most often the top benchmarks for DEA inefficient tractors. These results suggest that while John Deere appears to produce many quality tractors, competitor's like CNH and AGCO produce a few tractors that may be of even higher quality.

European and American suspension systems are described for improving the operator ride comfort on off-road vehicles. Analytical methods are then described to predict the dynamic behavior of a vehicle and human ride response criteria. The approach includes the selection of a terrain input to excite the vehicle model formulated by the generalized mechanical system simulation programs. An example involving an agricultural tractor-plow system is presented to illustrate the techniques.

Applications of active suspension control for both on-highway and off-highway vehicles are reviewed. Suspension design is evaluated in terms of ride vibration exposure and road/terrain handling. Active, semi-active, and slow-active suspension types are described in terms of their performance capabilities. Finally, numerous design concepts and their application to a wide range of ground vehicle types (i.e, truck, automotive, agricultural, and construction) are described.

The purpose of this paper is to describe and demonstrate a computer program to interactively design roller-chain and synchronous-belt drives. The program allows the user to optimize the power-transmission drive system and has graphics capability to assist in design visualization. The paper discusses the analysis procedure, design criteria, and the program data base. The analysis procedure and design criteria are based on accepted methodology by the roller-chain and synchronous-belt manufacturers. Governing equations and flow charts are included in the discussion, and three examples are presented to demonstrate the program capabilities and features.