I run a 56T on my fat 20" tire foldable w/ 7-speed freewheel. (The short fat tires offset the tall chainring just a bit). I've tried the same setup on my 26" beach cruiser but it just didn't work so good, so my 54T does the trick) I also use spider adapters make a dual front chain rings, adding shorter torque-minded chainrings.I run a 52t Lekkie Ring on a Bafang BBSHD but that is the largest chain ring Lekkie makes. There are higher tooth count chain rings advertised for the BBHSD but I've tried a few and they can't seem to get the offset correct. Is anyone actually running a chain ring higher than 52t on a BBHSD? If so I'd like to hear the details.
If I am in in hill country or sense any 'powertrain lugging' or want more torque, I just pull over and switch. You have to pay attention & use your gears to keep your motor spinning fast and If you experience any torque fall off, lugging or suspect heat, take it easy and gear it down.