it should be behind the driver side kick panal
75-140 synthetic
It is 235/75-15.
The stock tire size for a 4-wheel drive 1975 F250 is 235/75-15, 235 x 733 mm. The bolt pattern is 5x5.5, and the the offset range is -20 to 2.
31"/10.5" R16 or 265/75 R16
i have a 1968 ford f250 high boy its stock tire size is 235/85/16 but it will clear 35 inch tires or some 285/75/16
215/75/15
The original stock tire sizes for a 4-wheel drive model were 215 75 15, 225 75 15, and 235 75 15. They also had an option for 16, 17, and 18 inch tires.
My 87 Ranger 4x4 has factory 15"x6" with 205-75-15. Its printed on the inside of the drivers door.
Then either you bought it used or it was upgraded..you can look even on discount tires website or a variety of other websites ...the 2000 F150 came stock with 235/70R16! my 2000 f150 5.4L 4x4 came with 265 /75/ 17's my 2000 f150 5.4L 4x4 came with 265 /75/ 17's
265/75-16
P245/75/R16 or LT245/75/R16 for the stock rims
I got this information from the Michelin website: 1992 Ford Ranger 4X2 regular cab / super cab / P195 / 70 / R14 S ( alternate P 215 / 70 / R14 S ) 4X4 regular cab / super cab / P 215 / 75 / R15 S 4X4 regular cab V6 / P235 /75 / R15 S check the information sticker on the end of the drivers door