Hi everyone, new member here. My girlfriend got a new (2018) XC60 T8. I was going to get her the volvo ski racks for her roof, but can't find the answer to one question: Do the volvo ski racks also require Cross Bars be installed first, or do they mount directly to the runners on each side? Most brands (i.e. Thule), cross bars mount to the runners and the ski holders bolt to those. The Volvo brand ones don't appear this way from the images, but no one has been able to answer for me. Thanks so much.