A Sport touring motorcycle is a type of motorcycle that blends the performance of a sport bike

Sport bike

A sport bike, also written as sportbike, is a motorcycle optimized for speed, acceleration, braking, and cornering on paved roads, typically at the expense of comfort and fuel economy in comparison to less specialized motorcycles...

 with the long-distance capabilities of a touring motorcycle

Touring motorcycle

A touring motorcycle is a type of motorcycle designed for touring. Although any motorcycle can be used to tour with, manufacturers have brought specific models designed to address the particular needs of these riders...

, 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 996 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.

Differences to sport bikes

Engine designs are usually modified from their sport bike

Sport bike

A sport bike, also written as sportbike, is a motorcycle optimized for speed, acceleration, braking, and cornering on paved roads, typically at the expense of comfort and fuel economy in comparison to less specialized motorcycles...

 origins, the aim being improved mid-range torque rather than peak horsepower. Other differences from the sportbike class may include:

• A larger fairing
  Motorcycle fairing
  A motorcycle fairing is a shell placed over the frame of some motorcycles, especially racing motorcycles and sport bikes, with the primary purpose to reduce air drag. The secondary functions are the protection of the rider from airborne hazards and wind-induced hypothermia and of the engine...
  
   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
  Wheelbase
  In both road and rail vehicles, the wheelbase is the distance between the centers of the front and rear wheels.- Road :In automobiles, the wheelbase is the horizontal distance between the center of the front wheel and the center of the rear wheel...
  
   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
  Unsprung weight
  In a ground vehicle with a suspension, the unsprung weight is the mass of the suspension, wheels or tracks , and other components directly connected to them, rather than supported by the suspension...
  
  , giving the bikes a smoother ride over poor surfaces.
• ABS
  Anti-lock braking system
  An anti-lock braking system is a safety system that allows the wheels on a motor vehicle to continue interacting tractively with the road surface as directed by driver steering inputs while braking, preventing the wheels from locking up and therefore avoiding skidding.An ABS generally offers...
  
   is common on sports tourers, and some manufacturers offer linked brakes
  Combined braking system
  A combined braking system , also called linked braking system , is a system for linking front and rear brakes on a motorcycle or scooter. In this system, the rider's action of depressing one of the brake levers applies both front and rear brakes...
  
  
• 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

Honda ST series

The Honda ST series, also known as the Pan-European in some markets, fills the gap between touring-oriented sport motorcycles such as the CBR1000F and full-dress tourers such as the Honda Goldwing....

 engines, for example, have never been used in any other models. The Yamaha FJR1300's

Yamaha FJR1300

The Yamaha FJR1300 is the Yamaha Motor Company's largest sport touring motorcycle, currently in production as the FJR1300A and FJR1300AS .-History:...

 engine, though closely related to the 1,000 cc R1 sport bike engines in design, is only available in the sport touring FJR models.