Actually it's the size of the tire(s) contact patch and how much weight is concentrated per square inch time the tire air pressure (or whatever square measurement you want to use inch, metric, etc.,).

You can actually weigh a car by determining each tire's contact patch in square inches then multiply that contact patch by that tire's current air pressure. If the contact patch is 20 square inches and the tire pressure is 40 PSI (Pounds Per Square Inch) then that tire is supporting 800lbs. If it's the same at each of the four wheels (tires) then the vehicle weighs 3200lbs. Simple math. That's how they weigh giant mining trucks.

Do EV's run higher tire pressure and/or are the contact patches larger in square inches than non EV's or lighter vehicles?