Got a MOKI for your cartop carrier? https://www.rei.com/product/162968/rightline-gear-moki-door-step When at the store this afternoon, I saw a SUV with a cartop carrier just like my son Steven has on his car. He got a MOKI and uses it, so I told the lady at the store about it. If you have a cartop carrier for ‘extra’ stuff, this link for the MOKI is something to see.