Why do you refuse to show the proof? As someone else said, just do a replay showing the tires for each car.
Because it takes time. So here it is.
Here is everyone on RH for reference (1 lap). You're watching for the white BMW and Yellow Merc.
In this video, I set the white BMW and Yellow EVO to CH tires (the game said CS, which is their default). With me on RH, those cars are enormously out matched and dropped to the back fast. I pass all four before the end of the lap. Take note of how the Yellow Merc blows the corner at the top of the hill, which it does not do in any of the other examples.
Here, I fit myself with CS tires, but I fit the BMW and Merc with SS tires. They are still disadvantaged compared to the other Sophy cars, but faster than I am. If we are all on CS tires, I could keep pace.
Lastly, I put myself on SS. The BMW and Merc already had SS from the previous example. Note that now, I am on par with those cars. If they were on CS tires, rather than SS tires, I'd be able to blow past pretty easy.
And of course, there's the earlier video of me chasing those cars when they had RS tires on them. So, it appears to me, based on the performance differences, the HUD is incorrectly reporting the tires. We all know there are other variables that affect the races, but there's no way the tires settings are being ignored. If fact, if the settings were being ignored, why would all these cars with CS defaults be so obviously fitted with RH.
Almost all of my custom races are set up with everything on SS tires. How would that possible work if there were a tire change bug? It seems pretty obvious to me that the problem is in the HUD, not the car set up.
Please excuse the washed out video, it will process into properly mapped HDR in the next day or so, but in this video you can see that the Gr.3 AI cars are running Racing: Hard even though they're using my car, which has Comfort: Hards on it.
And beyond just the visual output, you can tell from the performance of the AI cars that they do indeed have Racing: Hards, and their tyre sticker confirms it's visually racing tyres as well.
The race starts at 1:13 in the video, before that is me showing the car I'm using and the event setup and confirming that my car is running Comfort: Hard tyres before starting the race.
This is showing that the visuals are broken, not the performance of the tire change. You're going slow, but so are all the other cars. You need to throw in a car with different tires.