Bike racks work by merging an adjacent vehicle with the carrier vehicle. The carrier canāt have any components at the same global co-ordinates as the carried vehicle. The carried vehicle keeps its global co-ordinates during the merge.
Flatbeds canāt work that way - you expect the carrier vehicle to have the flatbed components at the same global co-ordinates as the carried vehicle. ie, you expect to go from:
/--\
|##|
+--+
bbbb
b1bb o^o
bbbb #
bbbb o=o
that is, a quad-bike next to a flatbed, to
/--\
|##|
+--+
bbbb
bo^o
bb#b
bo=o
with the quad-bike on the flatbed.
It is super-hard to figure out that the flatbed space at ā1ā should be the location where the quad-bikeās front left wheel should end up unless both vehicles have the exact same facing. Like this:
/--\
|##|
+--+
bbbb
b1bb o^o
bbbb #
bbbb o=o
Itās not at all obvious to me how you sort that out.
Thereās a separate question of having multiple frames at the same vehicle co-ordinate, which can sometimes happen with wreckage but the game mostly assumes that wonāt happen and that weird behavior will happen when it does. Setting up a system to enable that is going to be tricky.
But a crane that just picks up a car and moves it around? I donāt think you run into any of those issues. You can use the existing code to displace the car to a new position and things should just work out.