I recently was building a trailer to carry 4 bikes from my home back out to california. And when looking for chocks i looked at the Bike Pro, Bike Vise, Bike Grab, the LA chock and the Smart Chock. And out of all of them the Smart Chock looked to be the best buy and after talking to customers. The security and peace of mind this gives me when trailering my bikes is amazing.
It works on two principles, the fact that the tire is not held upright by friction, this makes taking the bike in and out easy and adjustment even easier. The other principle is on using the weight of the bike to seat it in the chock.
As you roll your bike into the chock, it starts to lever forward and apply pressure on the rubber of the tire. The pressure applied is applied by the weight of the bike and once you are over the center, it seats forward and is in there. Now to remove all you do is rock your bike back.
For the price point at 251.90 for the freestanding it is an unbelievable deal.
Check them out at http://www.smartchock.ca