The Grant adapters are designed to lock the wheel mounting bolts in place. If you unscrew the bolts, you end up stripping the threads in the holes and the screws. I even read the assemnly info from the website which says you can use your existing wheel, which probably means you can just re-use the steering wheel, just not the hub.
It looks so far, like the detachable wheel hub has regular threads, but you never know.