The Trikke (pron.: // tr-EYE-k) is a three wheeled scooter-like vehicle designed and marketed by Trikke Tech Inc. The patented cambering mechanism allows the rider to propel this chainless, pedal-less human-powered vehicle without ever touching foot to ground. The design provides a stable 3-point platform that lets riders lean into the turns while all three wheels remain in contact with the ground.
The front wheel can be turned left and right using the handlebars, with the axis of rotation offset towards the front of the wheel. The rear wheels are connected to independent arms and are fixed to face directly forward. The independent arms are almost touching at the front end, and are around 30cm apart at the rear end. The rider stands on the two foot platforms above the rear wheels. The mechanism that joins the independent arms and the front wheel/handlebars structure allows all three wheels to remain touching the ground when the handlebars are leant to the left or right. The handlebars have two brake levers that control the brakes on the left and right rear wheels independently (although they are always both applied by the rider at the same time).
A Trikke is propelled using a motion that moves the vehicle along a curved S shaped path. The rider moves the vehicle from side to side at a rough cadence of one turn per second. Each turn requires the rider to turn the handlebars in the direction of the turn, lean the front structure towards the side they are turning, move their body weight toward the side they are turning, and push out slightly with the foot at the outside of the turn. The weight of the rider during a turn (or “carve”) is placed mainly on the foot at the outside of the turn. The inside foot will support very little weight and the rider will often lift the heel of this foot during the turn. There are many variations on the Trikke riding technique as riders place different emphasis on the elements of the movement.
The resulting motion is similar to a slalom skier carving down a mountain. The motion also has similarities to the tic-tac move on a skateboard.
A Trikke can be propelled without need to push off with your foot. Using the carving motion, a Trikke can achieve speeds of almost 30kph, but more often cruise at around 15kph. A Trikke can be ridden uphill, albeit at a reduced speed.
The key physics at work when riding a Trikke is the conservation of anglar momentum. This physics concept explains the acceleration of a rotating system (increase in angular velocity) when the mass of the system moves toward the axis of rotation (reducing the 'mass moment of inertia' or the resistance to rotational accelaration). This is the concept that explains how an ice skater spins faster when they pull their arms in toward their body. As a Trikke rider carves in one direction, they create a rotational system. The movement of bodyweight toward the direction of the carve therefore moves the weight of the system toward the axis of rotation. A careful study of the rotational speed of the front wheel will show it accelerating as the rider carves, then decelerating as the rider straightens up for the next carve. This motion is often simplified as 'shifting your bodyweight side to side', but in reality it is moving the mass of the system toward center of the alternating axes of rotation.
The Trikke was invented by Brazilian born engineer Gildo Beleski circa 1988. He had built a three wheeled scooter for riding downhill and discovered that once reaching the bottom of the hill, the scooter would continue further if he turned it left and right. He enhanced this concept and designed the Trikke cambering joint that is the central component of the vehicle.
Gildo established Trikke Tech in California, USA, in 2000. He formed a partnership with John Simpson, now Trikke Tech president, and they launched the Trikke to market in 2002.