Amazon.com description: Product Description: Hills, streams, and rocky terrain add a new dimension to the vigorous sport of bicycling. To prevent injuries from ruining excursions into the far reaches of the outdoors, cyclists should be prepared for the dangers of adventure by conditioning properly and by using safety equipment. Fine tume your bicycle with the latest accessories. Understand gear mechanisms and the proper use of them. Make repairs to your bike. Compete in races in your area. Discover a new and exciting way to challenge Nature.