In the various models I looked at, I recall (10+ years ago now) that some had strapped attachment points on the arms where you strap the bike frame to the rack, and some that did not. The former design is better. In 70+ mph driving with semis on the read, wind has not been any disruption at all. Mine are the 102 and the 103. One has only one bottom strap, but both racks are very secure.