rollbar
This is something to look into if you want to double or triple your fuel mileage-not a gimmick. About 40 min into the video he explains the physics behind the groove.
[url]http://gadgetmangroove.com[/url]
[url]http://www.youtube.com/watch?NR=1&v=8JTZKdXmiPQ&feature=endscreen[/url]
