So I'm going to need to get new tires for the '91 F250 Diesel soon. I've found that it is equipped with 235/85R16, and I would like to get something maybe a little beefier. Not alot bigger mind you but just a little wider and a tough grip so if I want to I can get anywhere with it. I'm confused as to what I need to do about size differences and my speedo/odometer readings. I've read you just have to keep the overall diameter the same but then how is it that you can put 44" tires on then? So what do I do?