Because they are a German company who gets some American lab to do some standard tire parametrization tests.

Germany has two state of the Art companies developing tire models and their parametrization and instead of relying on the decade of research and experience in that area they are ignoring it all and are going to some company around the world to get any data at all. This is just totally bizarre, they likely could have saved themselves a lot of time and money by just hiring a couple of guys from that sector and just implementing well studied approaches or just worked together with world leading experts in that field.

>They seem to take a bottom up approach and I think it's a decent way to do it.

If nobody else had ever done tire simulation, sure.

Could it be those companies are not interested in working with a small video game studio? In case they usually work with the much larger actors of the auto industry.

Or maybe they're operating at a level of fidelity much higher than the game needs? If they're working on simulation e.g. for Formula 1, they might be doing full fledged numerical simulation (FEM etc) rather than simplified models for real time games.

I'd be curious to know more though, what else do you know about this?

Tire simulations vary wildly amongst car sims. There certainly are many approaches to modeling tires, and many variables that can affect it. Beam is pretty good, I think they’re trying new stuff and it’s paying off.