The difference between an engine's power output and a bike's power output lies in their context and how the power is measured. Let's break it down:
Engine Power Output: The engine power output refers to the amount of power generated by the engine itself, usually measured in units such as horsepower (hp) or kilowatts (kW). It represents the total power produced by the engine before any losses occur due to various factors like drivetrain efficiency, friction, and accessories. Engine power output is typically measured at the crankshaft or flywheel.
Bike Power Output: The bike's power output, on the other hand, refers to the power delivered to the motorcycle's rear wheel, which is the power actually available for driving the bike forward. It takes into account the losses that occur in the drivetrain, such as the transmission, clutch, chain, and sprockets, as well as other mechanical losses within the motorcycle. Bike power output is usually measured at the rear wheel and is often referred to as rear-wheel horsepower (RWHP) or rear-wheel kilowatts (RWkW).
The power output at the rear wheel is always lower than the engine's power output due to these losses. The exact amount of power lost in the drivetrain depends on factors like the design of the motorcycle, the efficiency of the transmission, and the condition of the drivetrain components. As a result, the bike's power output is a practical measurement that reflects the usable power available for propelling the motorcycle and is a more accurate representation of its performance on the road.
It's important to note that when comparing power figures, it's essential to consider the units and whether they refer to engine power output or bike power output. Typically, the power specifications provided by manufacturers or in performance tests refer to engine power output, as it allows for consistent comparisons between different engines and vehicles.