for what its worth maybe helpful to someone, I spoke to a rep from Progressive asking what the recommended psi for their shocks was, his answer was they don't have recommended psi. check the height of the trike alone and then get on it and check it again. the drop should be about 3/4 of an inch. reading the post by DkCustom this is about spot on with his method. I am 200LBS at 25 PSI my suspension drops about 1/2 inch. I leave it this way so that when my wife is on with me the ride is even better. if I were riding alone a lot I'm thinking likely 22 psi.