I made the same brand switch back in Nov 2011 and kept the same tire size 285/60/18. However, going from all weather to AT light truck tires, here are some of my feedbacks. Living in hilly San Franciso with many pot holes, my mpg dropped a few while breaking in the tires. Going with stiffer AT LT tires, I think this is a given. It rides great and smooth outside the Bay Area. It does have an aggressive mountain handling ability with only a slight hum over 70mph. With the Dunlop, the LC felt like floating and not hugging the roads on the curvy Tahoe mountains. I have been keeping the psi at 35. I tried 40psi but I had no difference in mpg and it made the LC a little bit more bouncier. No regrets.