iRacing 2025 Season 4 Release brings new UI, cars, tracks and physics updates

A rebuilt Sim UI is the headline feature

The official notes describe the new Sim UI as rebuilt from the ground up using modern technology, tools, and design principles. iRacing says the goal is to power an advanced new UI framework and in-sim experience while still feeling familiar to long-time users.

For players, that matters because the UI is the front door to the sim. A more modern interface can affect everything from race preparation to navigation in-session, making the update relevant even to users who are focused primarily on driving rather than visuals or menus.

iRacing also says the new technology should enable significant future innovation and new sim experiences and features. That framing makes the Sim UI change more than a cosmetic refresh; it is positioned as part of a larger platform upgrade.

Three new cars expand the garage

The release adds three new vehicles to the iRacing garage: the Aston Martin Vantage GT3 EVO, the Dallara IL-15, and the Ford Mustang GT4.

The official notes say all three new cars come ready for rain racing. That is a practical detail for drivers, league organizers, and event planners because wet-weather compatibility can affect series design, practice planning, and race conditions.

iRacing also says AI Drivers are ready for competition with several of the new additions, including the Aston Martin Vantage GT3 EVO, the Dallara IL-15, the Ford Mustang GT4, and the NASCAR Gen4 Class Cars. For communities that run offline practice, AI-supported content broadens the utility of each release.

GT4, hybrid, NASCAR Gen4 and BMW M4 GT3 changes

Beyond the new cars, the 2025 Season 4 notes point to a multifaceted performance, tires, and physics overhaul for the entire GT4 class. The notes specifically mention rain tire updates as part of that work.

The hybrid system for vehicles has also been updated for improved realism, while the drafting parameters for the NASCAR Gen4 cars have undergone extensive adjustments to optimize the racing experience. In a sim where balance and racecraft often drive participation, these kinds of changes can influence how leagues, broadcasters, and drivers prepare for competition.

The BMW M4 GT3 has been updated to EVO spec with new physics and art. That is significant for racers who follow class evolution closely, because spec changes can alter both competitive behavior and visual presentation.

Track roster gets new and remodeled venues

On the circuit side, iRacing adds Autódromo Hermanos Rodríguez, the Mexico City track, to the world map. The notes call it legendary and say it arrives direct from Mexico City.

Several tracks have also been rescanned and remodeled, including Sonoma Raceway, World Wide Technology Raceway, Charlotte Motor Speedway, and North Wilkesboro Speedway.

In addition, six tracks have been overhauled with all-new artwork, including five on the NASCAR schedule and Oulton Park Circuit. The release also lists Chicago Street Course, Circuit of the Americas, Daytona International Speedway, Texas Motor Speedway, and Watkins Glen International among the modernized tracks. For streamers and organizers, this matters because updated venues can refresh long-running event calendars and keep familiar race environments from feeling static.

Localization and technical improvements widen the audience

The release notes also highlight European Spanish localization for much of the non-Sim iRacing application. iRacing says some areas of the application and the Sim itself still require translation work, and that additional languages are expected in the future.

Technical updates include a texture compression update and VR headset eye-tracking foveated rendering support. While these items are less visible than new cars or tracks, they can matter to users who care about performance, image quality, or VR hardware support.

For the wider player base, localization and technical support improvements can make the service easier to access and more comfortable to use, especially as the platform grows beyond its longest-standing audience.

AI racing receives wider coverage

iRacing says AI Racing is now available with four new cars: the Aston Martin Vantage GT3 EVO, the Ford Mustang GT4, and the NASCAR Gen4 Class Cars. The release notes also say AI Drivers have been retrained from scratch at Charlotte Motor Speedway, Sonoma Raceway, and World Wide Technology Raceway.

The new Mexico City track is also covered extensively for AI Drivers, with support for all seven track configurations. The notes add that AI Drivers are ready at North Wilkesboro Speedway - Oval and at Circuit of the Americas - NASCAR West.

That matters for training, practice, and content creation. Streamers who use offline sessions to rehearse racecraft or explain track limits can benefit from broader AI coverage, while tournament organizers and league admins may see more options for pre-event prep.

Why this update matters beyond patch notes

Taken together, the 2025 Season 4 release looks broad rather than narrowly targeted. iRacing is not only adding content, but also reworking presentation, physics, tires, drafting behavior, AI availability, and selected parts of the platform’s language support.

For gamers, the most immediate appeal is clear: more cars, more tracks, and more ways to race. For tournament organizers, the update can affect car choice, balance expectations, and the viability of both wet and dry events. For streamers, a rebuilt UI and refreshed track list can help keep content visually current and easier to present to viewers.

The official release notes also mention hundreds of meticulously engineered new vehicle setups, another detail that suggests the update is meant to support a wide range of driving styles and event formats rather than a single headline feature.

With the build already through tech inspection, iRacing’s season rollout is now positioned around the September 16 start date. The official Steam News post frames this as a major season reset, with enough structural changes to matter across casual play, organized leagues, and broadcasted competition alike.