You go by the manual of what Harley says is correct,not by what is shown on the tire.

 

On a softail with boards, it is impossible to get the front end to wash out before your tire starts to slide, at least that is my personal experience. If I ran 32 in my front tire it might last 2 months if i was lucky. I still run 40-42 in my front and 42-44 in my rear and do plenty of aggressive riding(as aggressive as can be done on a softail with floorboards) and have no issues at all.

Drew

 

DOT is very specific for tires. First off, every tire has the maximum psi on the sidewall and for beading purposes. Mine might say 50 psi but that's ridiculous! As most people agree, you should be around the 36-40 range, adjust it to your specific riding and bike. Any vehicle originally sold in the USA should have a psi and weight sticker. It's on the door jamb of automobiles and also the door itself. Bikes get em where they get em. Steering head and frame rails ( down tube on my Harley) is the usual.