i got a 1991 f250 ext cab and wondering what size tires would fit i got 285/75/16 on now just wondering if i can fit like 32 or 33s on her

 

i got 33s on my 78 bronco thats genaraly the max for stock fords

 

305/55/20 is what i run, i tend to rub when turning all the way to the left, or if i am turning to the left and hit a hard bump it will rub, not too bad though, they will fit just fine

 

285's are considered a 33 (33/11.50-16). That's about as big as you can go w/o mods.

 

You're running a 32.7 inch tire NOW!

width= 285mm * 0.039=11.115 inches
aspect ratio= 75, in a % is .75, *2 for rubber above and below rim = 1.5
rim= 16

Now, put it all together, width multiplied by aspect (*2), plus rim: 11.115 * 1.5 +16= 32.7.
32.7 is about the actual hieght of a 33 inch tire.

It's that easy.

 

its not that easy not all of us are math magicans

 

I am NO math magician! But I will say that I and others that I know have over analyzed the most simple math equations making them look like rocket science when we were done.

 

thats kind of what it looks like to me