The view clipping is showing at non-square resolutions. Some large planes (such as the grass or sky in the attached image) aren't displayed when running the game in non-square modes.

I believe it is because its off the track you are focusing on. Does the textures appear if you cahnge the resolution?

Quote from stevewhite :

I believe it is because its off the track you are focusing on. Does the textures appear if you cahnge the resolution?

Yes... it also occurs when the camera is (for example) positioned near the overpass at the long straight on Blackwood, looking towards the chicane (after the first corner (going clockwise)).

It really doesn't matter.. I think the occlusion culling just isn't working properly.

I've uploaded another image to demonstrate what I mean.

Could it be that it caused by the near- and far-plane settings? It seems that the problem only occurs when the camera is zooming in towards a car from a large distance (>150)

i have experienced the same when messing around with cameras.
when you switch to incar view and spectate a complete lap and switch then back to shift+u the missing patches are gone and everything looks fine again.

at least this works on my machine.

My question would be, why are you using resolutions that are like 512X1024?