Well if it were me I would probably try to use some math to drive both gears together. I don’t think you want to use collision and actually drive these like they would work in the real world where one gear meshes and physically drives the other one forward. Sure it might be possible but just using some math to drive them would be far more reliable. You still need collision so you can stand on them and objects don’t fall through but use some math to drive the motion. How you decide to actually set that up is entirely up to you.