Thought I'd pass on this simple modification to my Allen trunk rack which makes our two road bikes fit more "comfortably" on it.
The problem was that, given the angle of the support bars, the first bike doesn't hang straight down, but leans heavily against the rest of the rack. This bends the water bottle cage. The second bike hangs straight down, so the bikes aren't parallel.
Here's the view of the original arrangement (Before I realized I shouldn't have the derailleurs facing one another):
The easy solution was to buy some tubing and replace the original tubing with some that I cut to space the bicycles in a better arrangement. That is, I put more space between bike one and the rack, and less space between the two bikes:
(I had to cut one piece of tubing at an angle, because the 1 foot piece I bought wasn't quite enough).
Thus, they both hang down parallel to one another, and the first bike isn't mashed against the rack:
I tried it out yesterday, and it worked fine.