Schwinn High Timber Mountain Bikes, Multiple Sizes, Multiple Colors Schwinn steel mountain-style frame and Schwinn suspension fork combine for a durable and responsive riding experience 21-speed Shimano twist shifters and a Shimano rear derailleur for smooth, precise gear changes out on the trail Alloy linear pull brakes supply crisp all-condition stopping Light and strong alloy rims and hubs support knobby mountain tires for a durable riding experience Schwinn alloy cranks with triple chain rings offer optimal gearing and less maintenance on your end