The goal of my project is to create a bicycle trailer that assists the rider to go farther and faster over various terrains, functions like a shopping cart off the bicycle, and provides a modular cargo management system that carries more. To accomplish this goal, the package includes a hitch that doubles as fender, with a rigid joint connecting to a trailer with suspended wheels that leans with the bicycle, thus shortening the overall length of the footprint. The trailer is powered by a combination of brush-less electric motors mounted inside the arms, and flywheels housed inside the wheels themselves.

I have set out to solve a lifestyle problem for all cyclists who want to integrate the bicycle into everyday life. But the physical limitations of the rider, the mechanical constraints of the bike, and the lack of friendly roads are the greatest obstacles to this goal, even for the fittest and most experienced riders in a car dominated culture. Innovators have made many different attempts to improve bicycles’ range and carrying capacity, with electric motors, elongated designs, and other modifications. As effectively as these efforts serve their purposes, they require extensive modifications on the bicycles. Then some turned to trailers with promising results, since trailers are versatile and require little modification on the bicycles themselves. But like most other solutions, the trailer adds weight without providing extra power. So the idea of a trailer that provides extra power is born, and with it comes its own set of technical challenges. First, the issue of handling when power is put into the equation, because all existing trailers have flexible or free floating hitches, which is particularly hazardous when turning corners at high speed or if the rider accidentally hits the throttle while turning. Second, the issue of what to do with the trailer at the destination or grocery stops along the way, since trailers are easily stolen if left unattended. Therefore, it is ideal for the trailer to offer good cargo management solutions off the bike.

Being a cycling enthusiast and occasional racer, I view electric assistance beneficial but not necessary at all times. Therefore, an E-bicycle is not a very appealing sight in my garage next to the sleek race machines that riders like me would like to own. To motivate riders like me to commute more, who are physically capable and ride for fitness and training purposes, a versatile device such as a powered trailer is a welcome solution, because it allows us to acquire power only when necessary, then we can easily put it away when the mission is accomplished. The additional consideration added here to the brief is a competitive price point. The two electric motors, two flywheels, internal gearboxes and the development of a proprietary suspension system add to the cost, but the trailer still offers a competitive value at an estimated 1100 $ dollars MSRP because of its versatility, compared with high-end E-bicycles on the market (from 2000 to 6000 $ dollars MSRP).

I start off the project by examining what factors go into a cyclist’s decision-making about their commute. And the factors boil down to four: 1) weather, 2) distance, 3) terrain, 4) cargo. From these insights I set about listing the pros and cons of bicycle trailers in the context of commuting, and they narrow down to three each. The pros include: 1) extra storage space, 2) easy attachment to and detachment from various types of bicycles, and 3) flexibility in the types of cargo carried. The cons include: 1) the potential of tipping over while cornering with or without power, 2) extra weight holding you back on the hills, 3) reduced maneuverability due to extra length. After research and analysis, the form development stage explores a range of possibilities including a two-wheel cart with adjustable frame length depending on the size of the storage unit chosen. The problem is that the design is too elongated to maneuver freely in urban environments. Another direction explores single wheel designs which allow weight-saving, natural handling, and great aerodynamics. But these designs require a free floating hitch to turn properly, which is an unstable joint for power transfer. With the two concepts mentioned above eliminated, I research the market further, and two products catch my eye. First is the Ridekick trailer, the first market-ready electric trailer in history. Though its free-floating hitch does not seriously interfere with straight line handling, its overall length hinders tight corner maneuvers, and the trunk-like compartment limits the types of cargo it can carry. The second product is the Travoy made by Burley, a shopping-cart-like trailer promoted as an “urban” trailer because of its performance in tight corners and a load capacity of 60 lbs. Without power, however, a fully loaded Travoy will not go far unless towed by an extra capable cyclist. An analysis of these products poses two key questions. 1) How can I bring the motor closer to the bicycle to minimize handling issues? 2) How can I design a hitch to optimize power transfer? And I solve these questions by a key innovation—the introduction of a new steering system, with the two wheels independently suspended (tested with the wooden mock up), thus allowing the trailer to lean as the bicycle leans into corners, or to rock side to side when the rider stands on the pedals. This smart suspension system allows a low and fixed connection joint with the hitch and moves the wheels close to the bicycle’s center of mass, which creates not only a more stable ride but also better power transfer. To exploit the versatility offered by the “open-air-ness” of the trailer’s L-shaped frame, I devise a modular system to accommodate a variety of cargo shapes, from general purpose bags to large panel-shaped objects such as portfolio bags. There is also an option of hanging one bag on each side of the middle panels. The possibilities could be endless as long as the overall weight is within 60 pounds.

This high performance trailer gives every bicycle the potential to not only turn into an E-bike with ease, but also to become more versatile because of how usable the trailer is off the bike. These advantages give riders more incentive to use their bicycles more frequently for their everyday life, especially in this car dominated American transportation culture. And with a top speed of 19 mph without pedaling, this trailer can be a game changer for riders at all levels of capabilities.