I don't know if I totally understand what you are asking but, a good wheel chock, when the bike is at rest in it, the front wheel will be approximately 1 - 1 1/2" off the floor of the trailer.
If you go to this site you will see what I'm talking about on the display of MC2900. If you move the pin on the top of this Baxley Chock, you can get the front wheel on the floor, but ya better have help to get the bike up and off of the chock.
Scroll down some and on the left side is the Baxley chock. It is at rest where it should be in the trailer or on the floor and in use. Double click any picture for an enlarged view.
http://www.discountramps.com/wheel-chocks-straps.htm?gclid=CIWWh6HpvKMCFUcz5wodQQ4NdQ