Supersport bikes being limited to a top speed of 299 km/h (186 mph) is primarily due to a self-imposed industry agreement called the "Gentlemen's Agreement." This agreement was established among major motorcycle manufacturers, primarily based in Japan, in the late 1990s.
There were several reasons behind this agreement:
Safety Concerns: Supersport motorcycles are designed for high-performance riding, and their top speeds can exceed 300 km/h (186 mph) or more. Limiting the top speed to 299 km/h was a measure to address safety concerns regarding the increasing speeds of these motorcycles on public roads. By voluntarily capping the top speed, manufacturers aimed to discourage riders from engaging in high-speed contests on public streets.
Public Image: The motorcycle industry recognized that the perception of super-fast motorcycles being used on public roads could have negative implications for their image and could potentially result in stricter regulations or public backlash. The Gentlemen's Agreement was an attempt to show responsibility and self-regulation by limiting top speeds.
Insurance and Liability: Higher top speeds often come with increased insurance premiums and potential liability issues. By capping the top speed at 299 km/h, manufacturers could avoid some of these concerns.
It's worth noting that the Gentlemen's Agreement is not legally binding, and there have been instances where motorcycles have exceeded this speed limit in production models. However, most major manufacturers have adhered to this agreement for the reasons mentioned above.
It's important to recognize that while top speed is one aspect of a motorcycle's performance, there are various other factors, such as acceleration, handling, and braking, that contribute to a bike's overall performance and enjoyment.