Great bike rack for 4 or 2 bikes!
I love how you can quickly change this rack from a 4 bike rack to a 2 bike rack by removing one bolt and then sliding the secondary rack off. I drove with 2 bikes on the rack for an 8 hr round trip after I bought it and they held very secure the entire time. I have yet to try it with 4 bikes. Ignore the reviewer who mentioned that the vertical arms that clamp the bike frame can't rotate - the manual explains how to rotate them by first pressing a button to unlock them. It's a great feature!