Calls from the competing manufacturers for a new car formula were answered when the FIA approved the transition to Rally1 in June 2018, as part of a wider overhaul of both the WRC cars and the broader Rally Pyramid structure. The stated aims were to make the technology more relevant to road car development trends, reduce costs of development and repair, and introduce more sustainable energy use. A new top-level specification was considered necessary because the complexity and cost of World Rally Cars had grown substantially over 25 years of development.
Rally1 cars are defined under Article 262 of Appendix J of the FIA International Sporting Code. Unlike the Group A-derived World Rally Cars they replaced, Rally1 cars are classified as Category II purpose-built competition vehicles and carry no series production homologation requirement. They must, however, be visually identifiable as being based on a series production model, and can use either tubular space frame chassis or production bodyshells.
Key technical changes from the World Rally Car specification include: a reduction from six to five forward gears in common with Rally2; removal of active central differential technology; banning of liquid-cooled brakes; simplification of the turbocharger and fuel tank; removal of the fresh air valve from the anti-lag system; and the elimination of several aerodynamic components including rear diffusers and hidden cooling ducts. The existing 386 PS 1.6-litre global race engine continues in use. Cars wear an HV (high voltage) identification badge — white letters on a red background — due to the 750-volt electrical system.
A common safety cell structure was developed in partnership with the FIA and is mandatory across all Rally1 cars to reduce the cost of crash repairs and standardise protection levels. Synthetic fuels, claimed to be sustainable and renewable, are also mandated.
The hybrid electric power system is supplied identically to all competing teams by a single third-party supplier, Compact Dynamics, with batteries from Kreisel Electric. The system serves two functions: on liaison sections designated as electric-only zones by the rally organiser, it powers the car at 100% electric. On special stages it provides a boost of up to 100 kW (136 PS) alongside the combustion engine and recovers kinetic energy under braking.
Drivers select from three boost deployment modes and three regenerative braking recovery modes before each special stage begins, and cannot change these settings mid-stage. The hybrid unit adds 84 kg to the car's gross weight. Teams bore significant repair costs when hybrid units were damaged in stage incidents, and the hybrid system was discontinued ahead of the 2025 season after manufacturers collectively agreed the repair expense had become unsustainable.
Rally1 cars are limited to use exclusively in the World Rally Championship, entered only by manufacturer teams. They may appear at individual rallies outside championship rounds when entered by manufacturers but do not score points in those appearances.
The move to Rally1 coincided with significant restructuring of the Rally Pyramid, the FIA framework that governs how different car classes relate to each other across national, regional, and world championship levels. Rally2 cars, one tier below Rally1, use the same five-speed gearbox specification and serve as the primary platform for non-manufacturer teams competing for points in the WRC2 category.
Rally1 represents the most significant technical reset in WRC since the introduction of the World Rally Car in 1997. The removal of the production car homologation link — which had defined every top-level WRC formula since Group A in 1987 — marks a philosophical shift toward purpose-built competition hardware not unlike the original Group B concept, though with far more stringent safety structures and cost controls. The hybrid system, despite its discontinuation after only three seasons, demonstrated the WRC's willingness to integrate electrification into the highest level of rally competition ahead of many other off-road disciplines. Cars competing under Rally1 regulations have been fielded by Toyota, Hyundai, and Ford's M-Sport programme since the formula's introduction.