tandem penny-farthing bike lets two riders pedal it at the same time

"At its core, the custom ride is exactly what its name suggests: two identical high-wheel bicycles joined at their frames, facing opposite directions. Each side has its own large drive wheel, pedals fixed directly to that wheel, handlebars, and saddle. The result is a vehicle with no clear front or rear, and either rider can be the pilot, either direction can become forward motion, and steering inputs can come from both ends at once."

"Because both riders can steer, the tandem penny-farthing bike supports rear steering, counter-steering, and synchronized turning. When both riders gradually steer together, the bike can enter extremely tight circular paths. The design then is mechanically consistent, even if unintuitive. The failure of the 'crab walk' maneuver, where both wheels are angled to move sideways, reveals that the frame has its limits. When the riders abruptly turn or don't follow the same path and rhythm, they just fall sideways, just like on a normal bicycle."

"The bike can be ridden solo, but this proves unstable because of the uncontrolled steering at the unused end. More successfully, it can be ridden by two people working together, meaning one rider pedals forward while the other pedals backward, holding their handlebars rigid to stabilize the opposite wheel. In this setup, the bike becomes a cooperative, built-for-two system. Balance then depends less on individual skill and more on communication, timing, and restraint."

Two identical high-wheel bicycles are welded together, facing opposite directions, forming a tandem penny-farthing with no defined front or rear. Each side retains its large drive wheel, pedals fixed to the wheel, handlebars, and saddle, allowing either rider to pilot and choose direction. Both riders can apply steering inputs independently, enabling rear steering, counter-steering, and synchronized turning that can produce extremely tight circular paths. The frame limits prevent sideways 'crab walk' maneuvers, and abrupt or unsynchronized turns cause falls like on a normal bicycle. Dual-rider operation, with one pedaling opposite and the other holding the handlebars rigid, yields cooperative stability dependent on communication, timing, and restraint.

Read at designboom | architecture & design magazine