Of course, rather than a canned rumble-strip sound, LFS would need to implement physically-modelled audio based on the tyre surface hitting another surface... ;-)
Did you use extra soft suspension and tyre pressures here to accentuate the effect? :-)
Well it's definitely not the default helmet model, but I guess it's OK, since it has no collision models, just a visual model. And it has a different model format ".sre" not ".vob"