Exploring the Mechanics of the Hybrid Sports Bicycle

Prototypes showcased at auto shows often resemble futuristic, high-gloss spaceships, prioritizing aesthetics over practicality. While many are never intended for production, their striking designs captivate audiences.

Some prototypes, however, are designed for real-world use. The Hybrid Sports Bike (HSB), unveiled at the 2012 L.A. Auto Show, garnered significant attention as a groundbreaking hybrid bike developed by a graduate student over a year [source: Bubilek].

While many vehicles share features with the HSB, few combine them into a single, cohesive system. This all-in-one approach mirrors the convenience of universal remotes, smartphones, and multifunctional entertainment systems.

The Hybrid Sports Bike integrates three power sources, and its creator, Tomas Bubilek, utilized established methods of alternative transportation that have existed for decades. While these methods alone or in pairs have become technologically commonplace, they were once groundbreaking. One feature, in particular, might even have been slightly illegal.

The Hybrid Bikes We Know

Hybrid bicycles are not new. Typically, they merge human power, through pedaling, with an additional energy source, such as electric or gas.

Gas-hybrid bicycles emerged first, often as traditional bikes enhanced with aftermarket kits [source: NYCeW]. Riders have long had the option to attach small combustion engines to their bikes, effectively transforming them into gas-powered motorcycles with functional pedals. While not the safest mode of transport, it was a significant innovation. The engine can be activated or deactivated as needed, though such modifications are illegal in many parts of the U.S. [source: NYCeW]. These gas-bike hybrids often fall into a legal gray area.

The human-electric hybrid bicycle, a more modern, widespread, and costly yet entirely legal option, has been a notable advancement in eco-friendly transportation. Particularly in regions like the U.S., where nearly half of car trips are within a 2-mile (3.2-kilometer) range from home [source: USDOT], these bikes come in two primary types: one with an electric motor that activates automatically when extra power is needed, such as climbing a hill, and another where the rider manually controls the motor.

The Hybrid Sports Bike (HSB), as of its latest prototype in March 2013, employs a manual electric-hybrid system. Its uniqueness lies in incorporating gasoline into the hybrid mix, despite its drawbacks of being polluting, costly, and non-renewable.

Despite its use of gasoline, the HSB represents a potential breakthrough in greener transportation. Its design leans more towards a hybrid motorcycle than a bicycle, as noted by Bubilek, making it suitable for journeys extending far beyond short distances.

Other hybrid motorcycle designs, mostly prototypes, combine two power sources, such as human and electric or gas and electric [source: Ury]. The HSB stands out due to its ability to operate on human power alone, along with design features that enhance its maneuverability.

The HSB: Taking it Further

Internal combustion engines are rarely viewed as eco-friendly additions. While this is generally accurate, their advantage lies in their power output, which far exceeds that of electric motors.

The Hybrid Sports Bike stands out by utilizing three energy sources—human, electric, and gas—instead of the usual two. While the inclusion of fossil fuel doesn't enhance its environmental friendliness, it does make the bike a more practical substitute for fuel-intensive cars. It offers greater power, speed, and range compared to bikes relying solely on electric assistance.

The concept is straightforward: Similar to human-electric hybrid bikes, the HSB can serve as a car replacement for short urban trips. Even those with limited fitness can ride to the store with the help of an electric motor on hills. However, unlike traditional hybrids, the HSB is capable of handling longer journeys and busier roads more effectively.

The "tri-hybrid" HSB, often seen as an advanced hybrid bicycle, is more accurately described as a hybrid motorcycle. While human power is part of its energy mix, it isn't the primary source, according to Bubilek. Despite this, the bike retains a bicycle-like appearance, featuring 3-inch-wide (7.62-centimeter-wide) wheels, a traditional seat, pedals, gears, and handlebars. All bicycle functions remain operational, allowing for motor-free trips to nearby destinations.

For extended journeys and higher velocities, the bike offers a choice between two motors: electric and gas. Both are manually controlled using motorcycle-style handlebar switches. As of March 2013, the HSB's electric motor is a 1000-watt unit located in the rear wheel hub [source: Bubilek], with its battery housed in the front wheel hub.

The gas engine is a 110-cubic-centimeter four-stroke model positioned near the pedals. Its placement beneath the frame aids in maintaining a low center of gravity.

The gas tank, the sole heavy component, is mounted higher up, situated between the handlebars and the seat.

The design emphasizes weight distribution, with most heavy parts positioned at or below the midline. This configuration results in a low center of gravity, enabling the creation of a high-speed hybrid motorcycle that is slimmer and lighter than conventional models. Bubilek states the total weight is 150 pounds (70 kilograms), significantly less than the 500 pounds (225 kilograms) of a typical sports bike, with a top speed of 70 mph (112 kph) [source: Sport Rider]. This performance rivals that of an average gas-powered scooter and surpasses most range-limited electric models [source: Top Speed].

The legal status of this tri-powered bike remains uncertain, as it defies easy classification. However, the prototype showcases a creative step towards more sustainable transportation, potentially prompting updates to traffic laws as the hybrid movement progresses.

As of early 2013, the creator is awaiting investor interest in the Hybrid Sports Bike, which was well-received at the auto show. Bubilek notes, "The next iteration of the HSB is designed with mass production in mind."