nighthob said:They actually don't know. It was found in the earliest rulebook anyone could find, which was from the depression era. The NFL wasn't as thorough documenting the whys and wherefores as MLB, though it is as hidebound. During the whole George Brett fiasco they were able to look at the history of the pine tar rule and find that it was implemented during WWI as a cost-saving measure. The NFL isn't sure why the air pressure rule was implemented, but thanks to the shitshow that's Ballghazi they're doubling down.
Thanks, that's what I thought: back when the Bears were playing indoors.
As to WHY there's a rule, my own belief is that they wanted to add legitimacy to the rules, and the best/easiest way to accomplish that was to quantify as much as they could. I picture a dozen owners sitting around in a conference room: someone tossed a ball around the room, asked how it felt, everyone said OK/it's good, they measured it at somewhere around 13 psi, they added a half psi on either side, and voila: the magic range as an actual number.