They are so many reasons for the slack of the Car's crossbar, such as being hit by a car behind, or travel long distances on a bumpy road, which may cause this problem, nobody what crossbars pop off the rails, and so your RTT fall off like this:
but it can be avoided in a little bit of time, We have learned it from Mr. Shady, he has 30 years of experience of , at the beginning of the installation, as a 30 yr+ experienced mechanic engineering, he forsee this potential issues with crossbar mounting, so he designed this RTT Security wires.
There are 4 of these on the RTT, tying the SUV stock rails to the customer added cross bars.
The stainless steel straps and black plastic fasteners that were supplied with the RTT are plenty strong enough to secure the RTT to the cross bars; however, the weak link is securing the cross bars to the SUV (or other vehicle) stock roof rails. The wire rope fasteners provide the security that the RTT will remain tied to the SUV rails in the event the cross bars come loose during travel.