Modern Vespa

Liberty 150
I'm #250, it's a small bike, no surprise when I bottom out
The rear stock size 100/80 - 14" 54J, squirms a bit especially if I add a passenger
I think https://www.cyclegear.com/tires/michelin-city-grip-scooter-tires?sku_id=897655
Here's an explanation of the differences
https://www.jpcycles.com/how-to-read-motorcycle-tires

My experience is upping the load rating of the tire compared to stock, lets you run a little less air , a slightly smoother ride
5mm wider on each side & ever so slightly taller

The front forks will benefit from more preload & thicker oil

First look at load limits for bike. Over loading do not under inflate!