After re-positioning and re-tightening around 4 times on our tour so far, the clamp on Rhino racks have been relieved of their duties. The clamp on system does not tolerature corrugations and off-roading. They move around and have damaged my door seals and door frames.
I can say for sure that the racks didn’t move due to not being bolted tight enough. I made sure of that last time I re-tightened. Today I chewed out one of the bolt heads trying to undo it. A chisel came in handy to smash the bolt loose.
Replacement track mounted racks are on their way. In the post. The new ones screw into the roof. For my next task I have the pleasure of drilling holes in the roof of the car.