I placed an object (FBX file from blender) into the scene and add mesh collision onto it, save the whole thing and tested it on SP.

When i use a plane on top of it, it didn't turning and only move slowly on full throttle

but when i spawn let's say the bugger (blue offroad vehicle), it can turn, but the surface is very slippery when turning

any SP map maker or unity veteran out there know what's the problem. Im pretty new to unity so i might have missed some important things but didnt realize it ?

also spoiler, im making a map for SP