Originally held on Lombard Street, the BYOBW (Bring Your Own Big Wheel) Race has since moved to the somewhat more (or less?) twisty terrain on Potrero Hill at Vermont and 20th streets. This weekend, daredevils came in droves with their own Big Wheel or fun-size riding device (e.g., an office chair) to plunge down one of San Francisco's steepest hills. Here are some images from Sunday's breathtaking race. Enjoy.