I’m 5’10" and on race day sit at 145lbs but most of the time sit about 5-10lbs heavier and don’t have any trouble with them. I haven’t always run in 6-7oz shoes but as my form got better (much thanks to Newtons), I can’t run in anything heavier. For the last 3 open marathons and 5 open half marathons, I didn’t get so much as a blister or lost toenail but I also size up a little bit.