A Sport touring motorcycle is a type of motorcycle that blends the performance of a sport bike with the long-distance capabilities of a touring motorcycle, while providing comfort and relative safety to the rider. For the majority of the sport-tourer models on the market, manufacturers use an existing engine and technology from the current or last generation of their sport bikes. The Triumph Sprint motorcycle, for example, shared its engine with the Daytona, Speed Triple, and Tiger models. Similarly, Ducati sourced its 916 motor for its ST4 model. In some cases, whole sportbikes were re-invented as sport touring bikes. The 2000 Kawasaki ZX-6R sportbike became the 2004 ZZR600 with only a change in the front fairing bracket. This is cost effective because the maker can reuse existing tooling and parts, rather than creating a dedicated engine design from scratch.
Engine designs are usually modified from their sport bike origins, the aim being improved mid-range torque rather than peak horsepower. Other differences from the sportbike class may include:
A larger fairing than is implemented on sport-bikes, and an adjustable windscreen for better weather protection.
A frame that is usually designed from scratch to provide a more upright, less aggressive riding position ("all day comfort").
A longer wheelbase and more relaxed steering angle are usually also incorporated. These provide more straight-line stability than most sport bikes, but not to the degree that most pure tourers do. The addition of these heavier parts (full fairings, longer frames, heavier engine components) also serve to increase the ratio of sprung to unsprung weight, giving the bikes a smoother ride over poor surfaces.
A larger fuel tank to extend the range between fueling stops.
Ground clearance is usually left fairly high, permitting more sport-like riding on twisting roads than on a pure touring bike.
The sport-tourer class has become important and competitive enough that many manufacturers now offer purpose-built engines for their sport touring models. The Honda ST series engines, for example, have never been used in any other models. The Yamaha FJR1300's engine, though closely related to the 1,000 cc R1 sport bike engines in design, is only available in the sport touring FJR models.