Handcycle

Overview

A hand cycle is a three-wheeled cycle driven by the arms rather than the legs. It is used by people with spinal cord injury, amputation, or other conditions that limit leg use, and also by able-bodied athletes in the sport of handcycling. The rider sits low in a reclined recumbent seat and turns a pair of hand cranks mounted at chest height. That motion drives a chain to the single front wheel, which both pulls the cycle along and steers it.

The layout is a tadpole tricycle inverted in its drive: one front wheel does the work and two rear wheels provide stability. The Main Frame ties these together with a long backbone tube. A Drivetrain with a wide-range cassette lets the rider climb hills on arm power alone, the Brake System uses a front disc with a parking lock, and the Controls are concentrated at the cranks because the hands are busy driving and steering at the same time.

Frame and layout

The Main Frame is built around a central backbone tube of aluminum or chromoly, roughly 50 mm in diameter, that carries the rider's weight in bending between the rear axle and the front boom. The Front Boom reaches forward and usually telescopes so the crank-to-shoulder distance fits the rider's arm length. At the back, a cross tube sets a track width of 600 to 750 mm, wide enough to resist tipping when the rider leans into a turn. Seat mounts on the backbone allow fore-aft adjustment to dial in reach to the cranks.

Because the rider sits low and reclined, the center of gravity is close to the ground, which improves stability and reduces the chance of flipping during hard cranking or braking.

Hand-crank power

The defining subsystem is the Hand-Crank Unit. Two crank arms turn a sealed spindle through the crank bottom bracket set into the boom. Unlike bicycle pedals, the two arms are usually set in phase rather than opposite, so the rider cranks with both hands together, pushing over the top and pulling through the bottom. This synchronous motion lets the trunk and shoulders contribute to each stroke.

Each hand grip rides on a bearing so the palm keeps a comfortable orientation while the crank circles. Riders with reduced grip can use a hand cuff that straps the hand to the grip, so power transfers even without a firm hold. The first stage of gearing is the Crank Chainring bolted to the crank, typically 38 to 52 teeth.

Drivetrain

The Drivetrain has an unusually long chain run because the cranks sit far from the front-wheel cassette and the chain must cross the steering pivot. Two idler pulleys route the chain around the head tube so steering does not bind the drive, and a guide tube protects the rider from the moving chain. A Derailleur with jockey wheels indexes across an 8 to 11 speed cassette, often 11-34 teeth or wider, which gives the very low gears needed to climb grades on arm power alone. Arms produce far less sustained power than legs, so a broad, low gear range matters more here than on a leg-powered bike.

Steering and wheels

Most hand cycles steer by turning the whole crank-and-wheel module about the steering bearing in the head tube. As the rider leans and turns the cranks, the front module pivots and the front wheel points into the turn. The geometry is often tuned to return toward center, so the cycle tracks straight when the rider is just cranking. The Front Wheel carries the drive cassette and the brake rotor, laced with 36 spokes to a double-wall rim.

The two rear wheels are undriven supports on stub axles. Camber adapters tilt them a few degrees so the contact patches splay outward, widening the effective track and resisting tip-over in corners.

Seat, braking, and variants

The Seat Unit reclines the rider with a backrest to brace against, lateral supports to stay centered, and a lap belt for security. The Brake System uses a front disc caliper on a rotor, worked by a lever built into the crank grip so the rider never lets go to brake. A parking lock holds the brake during transfers in and out of the seat.

Three broad variants exist. Touring and recreational hand cycles favor comfort and gear range. Racing models, used in Paralympic competition, are lower and longer with aerodynamic seating and are grouped by classification. Power-assist versions add an electric motor controlled from the crank pod, extending range and easing hills for everyday transport. Some clip-on units even convert a manual wheelchair into a hand cycle by attaching a driven front wheel.