OK I read all through here looking for some answers and just ended up posting. I have an 02 FX4. What is the largest tire size that will fit on the stock rim? The torsion bars have been raised to level the truck by the previous owner. Just very confused as to sizing xxx/xx r xx and xx.x/xx

How do you convert convential tires size to figure 30, 31 ,33 tires?

Ok well technically I have 2 questions then.

 

Since you have a FX4, your truck came with 265/70-17 tires and 17x7.5 inch wheels. The first number is the width of the tires thread in millimeters (265mm). The second number is the aspect ratio (70), which is the relationship of the tires height to it's width. The third number of course, is the size wheel the tire mounts on (17 inches). That works out to be approximately a 32x10.50-17 tire. There are a couple of sites that have tire conversion calculators to convert P Metric sizes to floatation sizes, but I can't think of one.
As for what size you can run. You can stuff a 315/70-17 (35x12.50) tire on your truck with minor rubbing (on the frame at full steering lock) if you use the OEM wheels. Other options are 285/70-17's (33x11.50), 295/70-17's (34x12.00), 305/70-17's (34x12.50) or 305/65-17's (33x12.50).

 

Wow... Thanks for the great info. That makes a lot more sense.