You basically have to lower the Batmobile down to the ledge on the same level as the spikes and move left and right. The wheels of the Batmobile will cause the ring of spikes to rotate. Keep rotating to clear paths to go down as far as you can go.
The different slopes you can go down are numbered one to three. Just follow the order of the slopes to get down to the next level. For the first and second slopes, you'll want to turn it until you are over the spray painted bat logo for each level. The third level, you'll have to backtrack and go to the first and second slopes to open up the path.
