where you have this files from? the wheels are always in the ***_WHEELS.gtl file. there you find 6 wheel.DDS files(the capri has 2x6 because it has 2 styles, 1 for the RS3100 and 1 for the RS2600). 3x2D and 3x3D. you see the 3D rims only in the high detailed and the 2D rims only in the low detailed mode.
the black marked words are most important. it's the only way to get a full standalone without modifying the original ***_WHEELS.gtl
because the geometry files(*.GMT) are fixed linked to the texture files(*.DDS)
you need:
3x "FORD_CAPRI_2DWHEEL_STYLE10x.DDS" and 3x "FORD_CAPRI_WHEEL_STYLE10x.DDS"