Friction toys are a type of wheeled mechanical toy that use an inertia or friction wheel to power their movement. The spring attached to the vehicle’s friction wheel is wound by rolling the toy backwards with its tires pressed against a solid surface. While some use a cog to hold or discharge the spring’s energy, most simply unwind as soon as pressure is released from the vehicle, sending the toy speeding forward.

The invention of friction toys is credited to D.P. Clark, one of the founding members of the Dayton Group, a loose association of Ohio-based toymakers. Clark patented a friction flywheel system in 1897, the same year he initially organized his Dayton Friction Toy Works. Clark’s design led to the company’s series of popular “Hill Climber” friction toys which were produced through the 1930s. The toys were originally made from tin and wood parts assembled and painted by hand, with models ranging from chauffeur-driven sedans to circus trains.

During the mid-20th century most major model car manufacturers, like Marx and Corgi, sold friction toy series. Hot Wheels created particularly extensive lines of plastic friction-powered cars which performed tricks like raising into a wheelie or emitting sparks. Friction vehicles weren’t limited to model cars either; Japanese companies like Cragstan also made friction-powered model planes.