the wider the tire, the worse handling will be on-road.. the wide foot print seems to grab every groove in the road and follow it.. It seems that the 12.5" seems to be that happy medium where people can live with the side effects. If you go wider, your handling will get worse, narrower and it will improve. I have run 9.5",10.5", 14.5",15.5" wide tires and that has been my experience. I prefer the 12.5" myself, but if on road manners are top priority for you then I would go 10.5"