Moto3 replaced the 125cc category in Grand Prix motorcycle racing in 2012.
The new class was created as the championship’s lightweight entry category and marked a technical shift from the outgoing 125cc machinery. Moto3 bikes use 250cc, single-cylinder, four-stroke engines, replacing the 125cc class’s two-stroke motorcycles. The goal was to create a modern, cost-conscious category that could develop young riders before they progressed to Moto2 and MotoGP.
The 2011 season was the final year of the historic 125cc championship, which had existed since the Grand Prix world championship began in 1949. Moto3’s inaugural world championship was held in 2012, and Germany’s Sandro Cortese became its first champion aboard a KTM. The new category quickly became known for close racing because riders compete on relatively similar machinery and benefit strongly from drafting and group tactics.
Moto3 is sometimes confused with Moto2, but the two classes replaced different predecessors. Moto2 took over from the 250cc category in 2010, while Moto3 followed two years later and replaced the 125cc class. The answer is therefore the class name, not an engine size.