What size speakers fit in a 1994 Ford Ranger?

Answer 1

5 1/4 Front 5 1/2 x 7 1/2 Rear

Mine was different than the above answer.

My 1994 Ford Ranger Extra Cab with standard (non-premium) radio has 5x7 factory speakers in the doors. They had paper cones with whizzer cones for the high freqs and a foam surround that completely rotted away, leaving the cones free to flop around and produce virtually no sound. I didn't realize they were not working until I tried fading the sound to the front speakers exclusively. They were dead, dead.

Found that Kenwood KFC-C6882ie 6x8 are designed to fit Ford and Mazda 5x7 holes and screw patterns. Installed with minimal effort, though I need to use smaller headed #8x1/2" sheet metal screws, as the factor screws had large heads that didn't fit the Kenwoods. Was able to unsolder and remove the factory 2-pin socket from the factory speakers, bend the solder tabs a bit and solder the socket directly to the Kenwood power tabs, aligning the polarity correctly. That way I didn't have to cut the plug off the harness in the door.