Prediction of repair and maintenance costs of two-wheel tractors in Iran

Abstract

Predicting of repair and maintenance (R&M) costs of tractors in any mechanized farm is necessary for owners and managers to obtain information on overall maintenance costs in order to control production cost. In this context a study was conducted to predict accumulated R&M costs (Y) of two-wheel drive (2WD) tractors based on total usage hours (X) in Misagh-e- Sabz Agribusiness Company in Iran. Recorded data from the company was used to determine regression models for predicting total R&M costs (as percentage of initial purchase price) based on total usage hours. The statistical results of the study indicated that in order to predict total R&M costs of 2WD tractors with based on usage hours of 2260 h or less the power regression model Y = 0.013 (X/100)1.677 with R2 = 0.976, and to predict total R&M costs of 2WD tractors with based on usage hours of 2260 hours or more the polynomial regression model Y = 0.004 (X/100)2 – 0.181 (X/100) + 4.373 with R2 = 0.998 is strongly suggested. Results of the study also indicated that total R&M costs predicted in this study were lower than those predicted in the previous studies. Cumulative life of 12000 hours, for instance, indicated an total R&M costs equivalent to 40.3% of initial purchase price. The most likely reasons that explain these differences between the predicted results in this study and those predicted in the previous studies probably can be attributed to new tractor technology for production during the last two decades and lower labor wages in Iran.