Review on Yakima SweetRoll Roof-Mounted Boat Loader and Carrier for Vehicles, Holds 1 Boat by Dan Phillips

They do not work well with round Yakima Rails. They have a clamshell adapter for round bars. You can tighten them to your liking, but they will still rotate (it rotates very easily) when loading and transporting the kayak. I returned the Yakima round bars and bought a Thule CrossRoad kickstand, but even then I still had to put a thin rubber mat around the handlebars and then attach SweetRolls to it to keep them from spinning. The Thule handlebar is too rounded at the corners and doesn't offer a perfect mechanical fit, just a point contact that still gets the SweetRoll turning, but not at all like the round Yakima handlebar. By clamping the SweelRoll around the mat and square bar, the mat fills in the gaps and creates a good mechanical fit on all 4 sides, preventing the SweetRoll from spinning. They attach to your trunk without tools but I would recommend leaving them on the roof rack when not transporting the kayak as it takes a long time to line up all 4 pads for 1 kayak. I bought them because I wanted to drive the car into the garage without removing the kayaks. Also, they're easier to load (I'm 50 pounds) and I don't like laying them on my side as they act like a giant wind sail. I've recently seen several kayaks come loose in this position during transit