EXHIBIT 12.1 PACCAR Financial Corp. COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES PURSUANT TO SEC REPORTING REQUIREMENTS (Thousands of Dollars) Nine Months Ended September 30 1997 1996 - - -------------------------------------------------------------------------------- FIXED CHARGES Interest expense $ 75,238 $ 73,786 Portion of rentals deemed interest 187 183 - - -------------------------------------------------------------------------------- TOTAL FIXED CHARGES $ 75,425 $ 73,969 - - -------------------------------------------------------------------------------- EARNINGS Income before taxes $ 38,451 $ 39,256 Fixed charges 75,425 73,969 - - -------------------------------------------------------------------------------- EARNINGS AS DEFINED $ 113,876 $ 113,225 - - -------------------------------------------------------------------------------- RATIO OF EARNINGS TO FIXED CHARGES 1.51X 1.53X - - -------------------------------------------------------------------------------- The method of computing the ratio of earnings to fixed charges shown above complies with SEC reporting requirements but differs from the method called for in the Support Agreement between the Company and PACCAR Inc. See Exhibit 12.2. 10