After mounting a high rise canopy on our GM crewcab, we could no longer walk our 17', rotomould kayaks up the box and onto the roof. Just mounted our new Thule Hullavators and kayaks clear the canopy with room to spare. Very nice that you can remove the hydraulic section from the rack because otherwise, they are very heavy when you are trying to lift them onto your roof. If you have to leave the hydraulics when attaching your racks, especially on a high clearance vehicle, use two people and slide one end across the roof on a folded blanket or chunk of carpet, etc. The kayaks are easy to load and the hydraulics have no problem lifting their 65lbs on to the roof.