OK guys tire time and I have a few questions. First off I tow a lot so I am looking at only about a one inch lift on the front end, planning on staying with the stock 18" rims on my FX4 150. I am looking at the discover STT tires I would like to go with a little wider tire for a more "beefy" look. They offer several different tire sizes in the 18" rim my question is which one can I safely mount on stock rims with out any tire rubbing? Sizes are 35x12.5R18LT, LT275/70R18, LT275/65R18, LT325/65R18, LT305/60R18 & LT325/60R18.

 

You probably will not be able to use the 35" with only 1" of lift. Same with the 325/65R18. Stock is 275/65R18 so you could easily use that. The others would also fit, although the 305 and 325/60R18s may be too wide for a 7.5" rim. Check the manufacturers web site.
As you state you tow a lot, depending upon how much you tow, I would be careful about going much bigger. Bigger the diameter of the tire, the higher the final gear ratio and the lower your tow rating. If you go bigger, you may want to think about changing out the rears to a 4.10 or 4.56. Front and rear.

 

I wouldn't go wider than the 305's on the oem wheels.

 

The stock 275/65-18 are showing a size of 32.32 and a tread width 8.845.

The 305/60-18 have a size of 32.64 and tread width at 9.8 . If I go with the 305 that should not be big enough that I loose too much power for towing will it. Im thinking with the extra width on the 305 and that they will work on the stock rims with out rubbing I might be going with them.

 

I agree. I think that is your best choice.