There will be a gap between the roofrail and the crossbar where the clamps attach. There are a few minor upsides to the Rival 310:- The buttons have a slightly more satisfying click- The DPI toggle button is better positioned and much less likely to get pressed on accident. These have fantastic strong but cushioned arch supports and let me walk a long time without suffering. I am satisfied with these. Product has hot glue right on the front of it was a Christmas gift and its looks awful because the glue stands right out as soon as u hold up the sweater or put it on. I got a medium and am 5 foot 2, 138 lbs. 5 and got these in an 8 and they fit perfectly! However, as noted above, I found the click gave a slightly better tactile response than the non-clicky tactile version. They hold up well. Due to that, I was looking for sandals that were supportive and comfy - but still cute, and did not have the felt/suede lining that is disgusting when it gets wet.