This instructable took me 3 months to put together. Well, the actual project only took about an hour but I had to make sure it held up to all our Summer travel. Now that it's tested here's what I did.
Step 1: Cut the bars to length
The roof rack sits right on top of the cross bars. This particular rack has six bolts that protrude out. Accordingly, I drilled out 6, 1/4" holes in each bar. The holes at the ends are drilled all the way through so they can bolt together. To keep the holes in line i just measured and marked their positions along the seam of the conduit.
Step 2: Mount the bars to the rack
To improve the look of the finished product I added end caps to the ends of the bars.
Step 3: Prep your hardware
4, 1/4" bolts
16, 1" diameter 1/4" washers
4, 3/16" lock washers
4, 3/16" nuts
4, 3/4" conduit hangers.
To help with installation I cut grooves into each 1/4 bolt. You want them just long enough so they don't interfere with the conduit while they're sitting in the hangers. The bolts I bought were too long so I cut them down to 20mm long. That's the only modification you need to make.