I drive a Toyota Matrix, excellent car for transporting canoes or kayaks. I have a 48" bar on the roof, not quite wide enough for two canoes. My partner and I each own a canoe and we both sold the kayaks last year. To accomodate both canoes, I would have needed longer bars, which I was not happy with. To compromise, we built extensions onto the bars, which can be removed at a moments notice.
We used galvanized pipes, each about 24" in length. Electrical tape is used to tighten up the fit inside the rack bars. A piece of rubber tubing was placed on the ends where the gunwale brackets attach to make a tighter fit for them. Holes were drilled into each pipe as well as the rack bars and a screw with lug nut are used to fasten the pipes in place. The photos do the explaining.
