I put 285/75-16s on my truck and have had no problems. I do have the Powerpup to adjust the speedo. It might take your tranny a little time to learn the shifts for the 285s, but I have had no problems. I didn't notice any loss of power either. Of course, I hardly drive my truck at the stock setting, (TST advances the timing set a 0,0) but even when I do, I don't notice any difference driving it except it rides better than with the pizza cutters on it.