What's the narrowest tire you can put on a 18x10 inch rim

SOURCE: Snow Tires

This is going to effect your ABS and odometer readings. Suggest sticking with the 17 inch tires and can use your original rims.

SOURCE: 1993 6cyl dodge dakota 4x4 .

32 10/50 15 on ten inch rims

SOURCE: what is the largest tire you can put on a ford

most ford pickup rims are 15*7 its kind of a narrow tire therefore the biggest tires are 285/75. those will fit fine too big will rub, crack the sidewall, even cause a blow-out. you can go to your local goodyear and they will lookup your vehicle find the biggest-best tire fore your application, then give you a quote to take with you.

SOURCE: Rims and Tires for 1991 Ford Festiva

Check Ford's Mustang, same year (4cyl model)
Awesome little car, by the way!

SOURCE: what tire size can i use for my 17 inch rims on my 1998 audi a4

225/45's are what you are looking for.
That'll sort it out:)