Most old veteran two-wheel tire techs will tell you that putting an over-sized tire on a stock scooter wheel will actually pinch it out of it's designed shape - thus you have actually slightly reduced the contact patch of your tire. Only increasing the wheel rim width along with the tire width will increase the contact patch.
But after spending the $ for that bigger tire........
Not easy to convince the "bigger is better" folks that, without the wider rim, using stock PSI - you are not adding width to the contact patch, but just the opposite.
Stig