OK, what about a sheet of marine ply (1200x2400) or shorter, with various treated pine supports underneath.
Ply goes outside the garage door, onto driveway.
Level the top of the ply to the top of the floor, several treat pine supports along the length of the ply. Like a skateboard ramp.
So, ride ST into the garage, put ply sheet down, roll ST onto ply spin round roll back, hide ply.
Marine ply and treated pine can stay outside in the weather.
I can draw what i mean and post tonight if you want.