I went from a truck F350 just like you describe with 17 inch tires. I now have the 2011 F250 with 20 inch tires. These 2 trucks are the same height. I know because I can barely back into my garage without it touching. I did not have to adjust a thing to get bed to trailer clearance. I had a trailer at one time that was perfectly level with only about 4 inch clearance. It pulled horrible. I had to adjust my hitch to rise the 4 inch clearance. The funny thing with the raise in the front it pulled perfect. So a little nose high will not hurt a thing.