Loopwheels, made by Jelly Products Ltd, of Boughton in Nottinghamshire, are wheels for bicycles and wheelchairs that incorporate suspension into the wheel itself. The wheels have no spokes but, instead, six paired springs of carbon composite, fixed between the hub and the rim. They flex to accommodate unevenness in the ground over which they run, and even kerbs.
The springs, which allow the rim to travel up to two inches, serve also to reduce road noise and vibration, a perennial problem for users of small-wheeled bicycles - Loopwheels for bicycles are 20 inches in diameter. As the wheel itself provides suspension, hard tyres can be used, potentially eliminating punctures.
The springs are manufactured by KG Archery. Naturally, those of rear Loopwheels have a greater spring rate than those of front ones. The wheels can't unfortunately be fitted to a Brompton - there isn't enough room for the travel between the forks - but a folding Dahon Mu or Vigor will accommodate them.
Loopwheels were invented by Sam Pearce, a mechanical engineer and industrial designer. He got the idea in 2007, when he saw a mother pushing a buggy up a kerb, which caused the child on board to jolt forward. Sam's first prototype, made of wood and sections of plastic drainpipe, was made in 2009. The first generation of the product now available was launched in 2013.