Though there are no mountains to climb in South Florida, a few mountain biking tracks do require a substantial amount of technical expertise and endurance to conquer. Not Quiet Waters. It is neither a tire buster nor a dull flat track, and therein lies its attractiveness. The South Florida Trail Blazers volunteered to turn this lakeside trail into a legitimate track in the early '90s. Numerous large roots that beg to be jumped stand in the rider's way, and there's a modest 20-foot clay hill to climb. We are drawn to the "jungle section," where weaving in and out of bushes, trees, and shrubs is more fun than a bike jockey should be allowed to have. A more moderate novice track awaits those who are taking their first pedal down the mountain biking road. The most important advantage to this trial may lie in its all-season availability, for it is 90 percent in the shade. That relative coolness in summer turns the water-park pool you ride past into a casual thought, not a life-saving necessity.